Strong electron-Boson coupling effect in the infrared spectra of $Tl_2 Ba_2 Ca Cu_2 O_{8+de

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（完整版）原子核物理专业词汇中英文对照表

（完整版）原子核物理专业词汇中英文对照表原子核物理专业词汇中英文对照表absorption cross-section 吸收截面activity radioactivity 放射性活度activity 活度adiabatic approximation 浸渐近似allowed transition 容许跃迁angular correlation 角关联angular distribution 角分布angular-momentum conservation 角动量守恒anisotropy 各项异性度annihilation radiation 湮没辐射anomalous magnetic moment 反常极矩anti neutrino 反中微子antiparticle 反粒子artificial radioactivity 人工放射性atomic mass unit 原子质量单位atomic mass 原子质量atomic nucleus 原子核Auger electron 俄歇电子bag model 口袋模型baryon number 重子数baryon 重子binary fission 二分裂变binging energy 结合能black hole 黑洞bombarding particle 轰击粒子bottom quark 底夸克branching ration 分支比bremsstrahlung 轫致辐射cascade radiation 级联辐射cascade transition 级联跃迁centrifugal barrier 离心势垒chain reaction 链式反应characteristic X-ray 特征X射线Cherenkov counter 切连科夫计数器collective model 集体模型collective rotation 集体转动collective vibration 集体振动color charge 色荷complete fusion reaction 全熔合反应complex potential 复势compound-nucleus decay 复合核衰变compound-nucleus model 复合核模型compound nucleus 复合核Compton effect 康普顿效应Compton electron 康普顿电子Compton scattering 康普顿散射conservation law 守恒定律controlled thermonuclear fusion 受控热核聚变cosmic ray 宇宙射线Coulomb barrier 库仑势垒Coulomb energy 库伦能Coulomb excitation 库仑激发CPT theorem CPT定理critical angular momentum 临界角动量critical distance 临界距离critical mass 临界质量critical volume 临界体积damped oscillations 阻尼震荡damped vibration 阻尼震荡damped wave 阻尼波damper 减震器damping factor 衰减系数damping 衰减的damp proof 防潮的damp 湿气danger coefficient 危险系数danger dose 危险剂量danger range 危险距离danger signal 危险信号data acquisition and processing system 数据获得和处理系统data base 数据库data communication 数据通信data processing 数据处理data 数据dating 测定年代daughter atom 子体原子daughter element 子体元素daughter nuclear 子核daughter nucleus 子体核daughter nuclide 子体核素daughter 蜕变产物dd reaction dd反应deactivation 去活化dead band 不灵敏区dead time correction 死时间校正dead time 失灵时间deaerate 除气deaeration 除气deaerator 除气器空气分离器deaquation 脱水debris activity 碎片放射性debris 碎片de broglie equation 德布罗意方程de broglie frequency 德布罗意频率de broglie relation 德布罗意方程de broglie wavelength 德布罗意波长de broglie wave 德布罗意波debye radius 德拜半径debye temperature 德拜温度decade counter tube 十进计数管decade counting circuit 十进制计数电路decade counting tube 十进管decade scaler 十进位定标器decagram 十克decalescence 相变吸热decalescent point 金属突然吸热温度decarburization 脱碳decascaler 十进制定标器decatron 十进计数管decay chain 衰变链decay coefficient 衰变常数decay constant 衰变常数decay constant 衰变常量decay energy 衰变能decay factor 衰变常数decay fraction 衰变分支比decay heat removal system 衰变热去除系统decay heat 衰变热decay kinematics 衰变运动学decay out 完全衰变decay period 冷却周期decay power 衰减功率decay rate 衰变速度decay scheme 衰变纲图decay series 放射系decay storage 衰变贮存decay table 衰变表decay time 衰变时间decay 衰减decelerate 减速deceleration 减速decigram 分克decimeter wave 分米波decommissioning 退役decompose 分解decomposition temperature 分解温度decomposition 化学分解decontaminability 可去污性decontamination area 去污区decontamination factor 去污因子decontamination index 去污指数decontamination 净化decoupled band 分离带decoupling 去耦解开decrease 衰减decrement 减少率deep dose equivalent index 深部剂量当量指标deep inelastic reaction 深度非弹性反应deep irradiation 深部辐照deep therapy 深部疗de excitation 去激发de exemption 去免除defectoscope 探伤仪defect 缺陷definition 分辨deflecting coil 偏转线圈deflector 偏转装置deformation energy 变形能deformation of irradiated graphite 辐照过石墨变形deformation parameter 形变参量deformation 变形deformed nucleus 变形核deformed region 变形区域deform 变形degassing 脱气degas 除气degeneracy 简并degenerate configuration 退化位形degenerate gas 简并气体degenerate level 简并能级degenerate state 简并态degeneration 简并degradation of energy 能量散逸degradation 软化degraded spectrum 软化谱degree of acidity 酸度degree of burn up 燃耗度degree of purity 纯度dehumidify 减湿dehydrating agent 脱水剂dehydration 脱水deionization rate 消电离率deionization time 消电离时间deionization 消电离delay circuit 延迟电路delayed alpha particles 缓发粒子delayed neutron 缓发中子delayed proton 缓发质子deliquescence 潮解deliquescent 潮解的demagnetization 去磁denitration 脱硝density gradient instability 密度梯度不稳定性density of electrons 电子密度deoxidation 脱氧deoxidization 脱氧departure from nucleate boiling ratio 偏离泡核沸腾比departure from nucleate boiling 偏离泡核沸腾depleted fuel 贫化燃料deposit dose 地面沉降物剂量deposited activity 沉积的放射性deposition 沉积deposit 沉淀depression 减压depressurization accident 失压事故depressurizing system 降压系统desalinization 脱盐desalting 脱盐descendant 后代desorption 解吸detailed balance principle 细致平衡原理detection of radiation 辐射线的探测detonation 爆炸deuteride 氘化物deuterium alpha reaction 氘反应deuterium 重氢deuton 氘核deviation 偏差dew point 露点dextro rotatory 右旋的diagnostic radiology 诊断放射学diagnostics 诊断diagram 线图diamagnetism 反磁性diameter 直径diamond 稳定区;金刚石diaphragm 薄膜diatomic gas 双原子气体diatomic molecule 二原子分子dielectric 电介质differential control rod worth 控制棒微分价值differential cross section 微分截面diffraction spectrometer 衍射谱仪diffraction spectrum 衍射光谱diffraction 衍射diffuse 扩散diffusion stack 务马堆diffusion theory 扩散理论diffusion time 扩散时间diffusion 扩散dilution 稀释dipole 偶极子dirac equation 狄拉克方程direction 方向discharge 放电discrete 离散的disintegrate 蜕衰disintegration 蜕变dislocation 位错disorder 无序dispersion 分散displacement current 位移电流displace 位移;代替dissociation 离解dissolution 溶解distillation 蒸馏distortion 畸变divergence 发散domain 磁畴Dopper effect 多普勒效应dose albedo 剂量反照率dose build up factor 剂量积累因子dose equivalent 剂量当量dose rate 剂量率dose 剂量down quark 下夸克dry out 烧干duality 二重性duct 管dysprosium 镝endothermic reaction 吸能反应energy conservation 能量守恒even-even nucleus 偶偶核exchange force 交换力excited state 激发态exothermic reaction 放能反应exposure 照射量fatigue 疲劳feedback 反馈fermi age 费米年龄fermion 费米子fermium 镄fermi 费米Feynman diagram 费恩曼图field theory 场论fine structure 精细结构fissile 分裂的fissionable 分裂的fission barrier 裂变势垒fission fragment 裂变碎片fission product yield 裂变产额fission product 裂变产物flattening of neutron flux 中子通量展平fluorescent x rays 荧光x射线fluorine 氟flux 通量forbidden band 禁带force 力francium 钫free electron 自由电子free energy 自由能frenkel defect 弗兰克尔缺陷frictional force 摩擦力fuel assembly grid 燃料集合体栅格fuel assembly 核燃料组件fuel cell 燃料电池fuel depletion 燃料贫化fuel reprocessing 燃料后处理function 函数fusion 核聚变galaxy 星系Gamow-Teller interaction G-T相互作用gauge boson 规范波色子gauge field theory 规范场论Geiger-Mǖller counter 盖革-米勒计数器Geiger-Nuttal law 盖革-努塔尔定律geometrical cross-section 几何截面germanium detector 锗探测器giant resonance 巨共振gluon 胶子grid ionization chamber 屏栅电离室hadron 强子heavy ion 重离子helicity 螺旋性Higgs particle 希格斯粒子Hubble constant 哈勃常量Hubble law 哈勃定理incoming channel 入射道incoming particle 入射粒子independent-particle model 独立粒子模型induced fission 诱发裂变inelastic collision 非弹性碰撞inelastic scattering 非弹性散射inertial confinement 惯性约束internal conversion 内转换intrinsic electric quadrupole moment 内禀电四极矩intrinsic parity 內禀宇称island of isomerism 同核异能素岛island of stability 稳定岛isobaric spin,isospin 同位旋isobar 同量异位素isomer 同核异能素isospin analog state 同位旋相似态isospin multiplet 同位旋多重态isotone 同中异位素isotope 同位素j j coupling j j耦合joule heat 焦耳热jump function 阶跃函数junction particle detector 结型粒子探测器kerma rate 比释动能率kerma 柯玛kernel approximation method 核近似法kernel function 核函数kernel 核kerr cell 克尔盒kerr effect 克尔效应kevatron 千电子伏级加速器key measurement point 关键测量点k factor 增殖系数kinetic theory of gases 气体运动论kirchhoff's radiation law 基尔霍夫辐射定律klein gordon equation 克莱因戈登方程klein nishina formula 克莱因仁科公式knight shift 奈特移位knocking out 原子位移knock on atom 撞出原子knock on 撞击撞出krypton 氪k shell k 层Kurie plot 库里厄图labeled 示踪的labile 不稳定的lag 延迟laminar flow 层流lande g factor 朗德因子lanthanides 镧系lanthanum 镧laplace's operator 拉普拉斯算符laplacian 拉普拉斯算符larmor frequency 回旋频率laser cooling 激光冷却laser enrichment process 激光浓缩法laser isotope separation method 激光同位素分离法laser pulse 激光脉冲laser 激光latent energy 潜能lattice cell 栅元lattice constant 晶格常数lattice defect 点阵缺陷lattice energy 晶格能量lattice parameter 晶格常数lattice 格子laue photograph 劳厄照相lawrencium 铹Lawson criterion 劳森判据lead 铅lepton 轻子level 能级liberation 游离limit 极限liquid metal 液态金属liquid model 液体模型liquid phase 液相lithium 锂load 负荷lorentz force 洛伦兹力lorentz gas 洛伦兹气体lorentz invariance 洛伦兹不变性low activity waste 低放废物lower limit 下限lutetium 镥macroscopic cross section 宏观截面macroscopic state 宏观态magic number 幻数magnesium 镁magnetic dipole 磁偶极子magnetic field 磁场magnetic resonance 磁共振magnetism 磁manganese 锰many body forces 多体力many body problem 多体问题mass abundance 质量丰度mass energy conversion formula 质能换算公式mass excess 质量过剩mass range 质量射程mass spectrometer 质谱仪maximum 最大值maxwell boltzmann distribution 麦克斯韦分布函数mean collision time 平均碰撞时间mean field 平均场mean value 平均值mean 平均melting point 熔点membrane 薄膜memory 存储mendeleev's law 门捷列夫周期律mendelevium 钔mercury 汞meson exchange theory 介子交换理论meson field theory 介子场理论meson 介子meson 介子metamorphose 变形methane 甲烷methanol 甲醇methyl alcohol 甲醇migration 移动mobility 迁移率moderate 减速moderation 减速modulus of elasticity 弹性模数modulus of rigidity 刚性模数modulus of rupture 断裂模数modulus of torsion 扭转模数modulus 刚性模数moisture 湿气molar fraction 克分子分数molecular mass 分子质量molecular orbital 分子轨函数molten salt 熔盐molybdenum 钼monte carlo method 蒙特卡罗法neodymium 钕neon 氖neptunium 镎neutrino 中微子neutron flux 中子通量neutronics 中子物理学neutron 中子nickel 镍niobium 铌nitrogen 氮nobelium 锘nominal value 公称值nuclear fission 核裂变nuclear fission 核裂变nuclear force 核力nuclear fuel 核燃料nuclear spallation 核散裂nucleon 核子nucleus 核nuclide 核素nu factor 每次裂变后的中子产额ood-A nucleus 奇A核ood-ood nucleus 奇奇核optical model 光学模型orbital angular momentum 轨道角动量orbital electron capture 轨道电子俘获pair creation，pair production 对产生pairing correlation 对关联pairing energy 对能parent nucleus 母核parity 宇称partial-wave analysis 分波分析partial-wave cross-section 分波截面particle physics 粒子物理photoelectric effect 光电效应pick-up reaction 拾取反应polarization 极化度potential barrier 势垒prompt neutron 瞬发中子proportional chamber 正比室proton radioactivity 质子放射性proton 质子quark confinement 夸克禁闭quark-gluon plasma 夸克-胶子等离子体quark model 夸克模型quark 夸克radiation damage 辐射损伤radiation dose 辐射剂量radiation protection 辐射防护radiative capture 辐射俘获radioactive dating 放射性鉴年法radioactive equilibrium 放射性平衡radioactive nuclide 放射性核素radioactive series 放射系radioactivity 放射性range 射程reaction channel 反应道reaction cross-section 反应截面reaction energy 反映能reaction product 反应产物reaction yield 反应产额recoilless resonance absorption 无反冲共振吸收residual interaction 剩余相互作用residual nuclease 剩余核resolution 分辨率resolving time 分辨时间resonance cross-section 共振截面resonance energy 共振能量resonance state 共振态rotational energy level 转动能级saddle point 鞍点samarium poisoning 钐中毒samarium 钐scalar 标量scandium 钪scattering 散射scheme 图解Schrodinger equation 薛定谔方程scintillation detector 闪烁探测器scram control 快速停堆控制scram discharge volume 快速停堆排放量scram rod 安全棒selenium 硒self absorption coefficient 自吸收系数self absorption 自吸收self adjoint matrix 自共轭矩阵self adjoint operator 自共轭算子self adjoint 自轭的semiconductor 半导体sensitivity 灵敏度series 系;级数shell model 壳层模型shell structure 壳层结构shim rod 补偿棒shim 补偿shut off rod 安全棒silicon 硅simulation 模拟singularity 奇性slab reactor 平板反应堆slow down 减速slowing down area 慢化面积small angle scattering 小角散射sodium fluoride 氟化钠sodium 钠soft component of cosmic rays 字宙射线的软成分solar cosmic ray 太阳宇宙线solar neutrino 太阳中微子solar x ray 太阳x 射线solenoid 螺旋管solid angle 立体角solid phase 固相solid solution 固溶体soluble 可溶的solute 溶质source data 源数据source strength 源强度space group 空间群space lattice 空间点阵spacing 间距spallation 散裂special relativity 狭义相对论special report 专题报告special theory of relativity 狭义相对论specific activity 比放射性specific binding energy 比结合能specific burn up 比燃耗specific charge 比电荷specific concentration 比浓度specific 比的specimen 试样spectral line 光谱线spectral series 光谱线系spectrum 谱speed 速率spent nuclear material pool 烧过的核材料贮存池sphere 球spherical reactor 球形反应堆spherical wave 球面波spin angular momentum 自旋角动量spin dependent force 自旋相关力spin 自旋splitting of energy levels 能级分裂splitting ratio 分开比spontaneous decay 自发衰变spot 斑sputtering 飞溅square bracket 方括弧stable equilibrium 稳定平衡stainless steel 不锈钢standing wave 驻波stark effect 斯塔克效应statistical error 统计误差statistical fluctuation 统计涨落statistical mechanics 统计力学statistical straggling 统计涨落statistical uncertainty 统计不确定性statistical weight 统计重量statistical 统计的statistic analysis 统计分析statistics 统计学statistics 统计性质steam generator 蒸汽发生器steam void 汽穴steam 蒸汽stefan boltzmann ] constant 斯蒂芬玻尔兹曼常数stern gerlach experiment 斯登盖拉赫实验stochastic process 随机过程stoichiometry 化学计算法stokes'law 斯特克斯定律stopping power 阻止本领strangeness number 奇异数strangeness 奇异性strange particle 奇异粒子strange particle 奇异粒子strange quark 奇异夸克strength function 强度函数strontium 锶structure factor 结构因子subcritical assembly 亚临界装置subcritical 亚临界的subgroup 子群sublimation 升化subprogram 子程序subroutine 子程序subscript 下标subtraction 减法sulfur 硫superconductivity 超导性superconductor 超导体supercooled 过冷的superheated vapor 过热蒸汽superheated 过热的superlattice 超晶格superposition principle 迭加原理superposition 重叠supersaturation 过饱和superscript 上标surface tension 表面张力susceptibility 磁化率suspension colloid 悬浮胶体swelling 膨胀switch 开关symmetry 对称性synchrotron radiation 同步加速辐射synthesis 合成system of atomic units 原子单位制threshold energy 阈能time-of-flight 飞行时间top quark 顶夸克total cross section 总截面track detector 径迹探测器transfer reaction 转移反应transition probability 跃迁概率two-component neutrino theory 二分量中微子理论unclean separation energy 核子分离能unified model 综合模型unique forbidden transition 唯一性禁戒跃迁up quark 上夸克uranium series 铀系vector boson 矢量波色子vibration energy level 振动能级volume energy 体积能weak interaction 弱相互作用yrast line 转晕线yrast state 转晕态。

How long does it take for the Kondo effect to develop

a r X i v :c o n d -m a t /9903240v 1 [c o n d -m a t .m e s -h a l l ] 15 M a r 1999How long does it take for the Kondo eﬀect to develop?Peter NordlanderDepartment of Physics and Rice Quantum Institute,Rice University,Houston,Texas 77251-1892Michael Pustilnik and Yigal MeirPhysics Department,Ben Gurion University,Beer Sheva,84105,IsraelNed S.WingreenNEC Research Institute,4Independence Way,Princeton,NJ 08540David ngrethDepartment of Physics and Astronomy,Rutgers University,Piscataway,NJ 08854-8019The time-development of the Kondo eﬀect is theoretically investigated by studying a quantum dot suddenly shifted into the Kondo regime by a change of voltage on a nearby ing time-dependent versions of both the Anderson and Kondo Hamiltonians,it is shown that after a time t following the voltage shift,the form of the Kondo resonance matches the time-independent resonance at an eﬀective temperature T eﬀ=T /tanh(πT t/2).Relevance of the buildup of the Kondo resonance to the transport current through a quantum dot is demonstrated.PACS numbers:72.15.Qm,85.30.Vw,73.50.MxThe Kondo eﬀect in quantum dots has been observed in several recent experiments [1].Beyond verifying the-oretical predictions [2,3],these experiments demonstrate that quantum dots can serve as an important new tool to study strongly correlated electron systems.Unlike magnetic impurities in metals,the physical parameters of the quantum dot can be varied continuously,which allows,for example,systematic experimental study of the crossover between the Kondo,the mixed-valence,and the non-Kondo regimes.Moreover,the quantum dot sys-tem opens the possibility of directly observing the time-dependent response of a Kondo system,as there is a well developed technology for applying time-dependent per-turbations to dots [4].Along these lines,several theoret-ical works have addressed the behavior of a Kondo impu-rity subject to ac driving [5].However,a clearer picture of the temporal development of many-body correlations is obtained if the impurity is subject to a sudden shift in energy.Speciﬁcally,by applying a step-like impulse to a nearby gate,the dot can be suddenly shifted into the Kondo regime,and the buildup of the correlated state observed in the transport current.In this Letter,we analyze the behavior of a quan-tum dot following a sudden shift into the Kondo regime.The time-dependent spectral function is evaluated within the non-crossing approximation (NCA)[3,6–8],as is the transport current in response to a pulse train.The latter provides an experimental window on the development of the Kondo resonance.Employing the Kondo Hamilto-nian,we show that a ﬁnite development time t is pertur-batively equivalent to an increase in the eﬀective tem-perature.We treat a quantum dot coupled by tunnel barriers to two leads (inset to Fig.2).Only one spin-degenerate level on the dot is considered,which is a good approximation at low temperatures.A time-dependent voltage V g (t )is applied to a nearby gate,causing a proportionate shift in the energy of the level ǫdot (t ).If the Coulomb inter-action between electrons prevents double occupancy of the dot,the system is described by the U =∞Anderson Hamiltonian for a magnetic impurity,σǫdot (t )n σ+ kσǫkσn kσ+(V k c †kσc σ+H .c .) ,(1)with the constraint that the occupation of the dot cannot exceed one electron.Here c †σcreates an electron of spin σin the quantum dot,with n σthe corresponding number operator;c †kσcreates an electron in the leads,with k rep-resenting all quantum numbers other than spin,including the labels,left and right,for the leads.V k is the tunnel-ing matrix element through the appropriate barrier.The quantum dot is occupied by a single electron provided the level energy ǫdot lies at least a resonance width Γdot [9]below the chemical potential of the leads.At low temper-atures,the resulting free spin on the dot forms a singlet with a spin drawn from the electrons in the leads –this is the Kondo eﬀect.The Kondo temperature,beneath which the strongly correlated state is established,is given by T K ≃D ′exp(−π|ǫdot |/Γdot ),where D ′is a high en-ergy cutoﬀ[10].The signature of this correlated state is a peak at the Fermi energy in the spectral density of the dot electrons.This peak,in turn,dramatically enhances transport through the dot,allowing perfect transmission−6.0−4.0−2.00.0ε0.00.51.01.52.02.5ρd o t (ε,t )−0.10.00.1εt<0t=13.8t=27.6t=82.8t=193t=759FIG.1.Spectral density ρdot (ǫ,t )vs.energy ǫat various times following a step-function change in the level energy ǫdot (t )=−5+3θ(t ).The ordinates for positive times are successively oﬀset by 0.5units.For t <0,ρdot (ǫ,t )is iden-tical to the equilibrium spectral density at ǫdot =−5while for the largest time shown it is indistinguishable on this scale from the equilibrium spectral density at ǫdot =−2.Through-out this work energies are given in units of Γdot ,and times in units of 1/Γdot ,with ¯h =1.Here T =0.0025.at zero temperature [2].We employ the non-crossing approximation (NCA)to analyze the spectral density and transport through the dot in the presence of a time-dependent level energy ǫdot (t ).The NCA is based on an exact transformation of the U =∞Anderson model in Eq.(1)into a slave-boson Hamiltonian [6].The latter is then solved self-consistently to second order in the tunneling matrix el-ements V k .The NCA approximation gives reliable re-sults for temperatures down to T <T K ,and its time-dependent formulation has been discussed at length in previous works [7,8].We deﬁne a time-dependent spec-tral density for the dot electrons as [11]ρdot (ǫ,t )≡Re∞dτ2ψα′,S =ββ′c †βσββ′t t’t t’t=0-t=0+t=0+t=0-FIG.3.Contributions of order J 2to the renormalized con-duction electron scattering vertex,from the Kondo Hamilto-nian in Eq.(3).Solid lines are conduction electron propaga-tors and dashed lines are pseudofermion propagators.Sum-mation over internal spins is implied.pseudofermion number is conserved by H K +λn c ,and wehave n c =0for t <0because of the large pseudofermion energy λ→∞,we obtain an abrupt turn on of the Kondo coupling at t =0and all later expectations are taken in the physical subspace n c =1.The analytical signature of the Kondo eﬀect is the log-arithmic divergence of perturbation theory in the dimen-sionless coupling Jρ,where ρis the density of conduction electron states per spin direction at the Fermi level.In-deed,for T <T K perturbation theory in Jρfails,even for small Jρ.For T >T K ,temperature cuts oﬀthe logarith-mic divergencesand perturbationtheoryis reliable [14].We ﬁnd that a ﬁnite time t following a sudden switching on of the Kondo coupling also results in a convergent per-turbation theory.To demonstrate this,we focus on the simplest quantity that diverges in perturbation theory.Speciﬁcally,we calculate the scattering vertex γpp (t,t ′)to order J 2.Physically,this quantity represents the low-est order change in J due to multiple scattering from the Kondo impurity.Since abruptly turning on the Kondo coupling creates a nonequilibrium state of the system,we use Keldysh Green functions with p =±1for the out-ward/backward branches.In time,the Keldysh contour runs from −∞to ∞(p =+1)and then from ∞to −∞(p =−1).As shown in Fig.(3),there are two contri-butions at order J 2,one with the conduction electron line and the pseudofermion line parallel and one with the lines antiparallel.Evaluating the diagrams in Fig.(3),and keeping only logarithmically divergent contributions in addition to the bare vertex,we ﬁnd γpp ′(t,t ′)=pδpp ′J2G pp 0(t −t ′)sgn (t −t ′).(4)(Note that in this order there is no logarithmic contri-bution that is oﬀ-diagonal in the Keldysh indices.)HereG pp 0(t −t ′)is the bare time-ordered (for p =+1)or anti-time-ordered (for p =−1)Green function for conduc-tion electrons at the site of the Kondo impurity.For|t −t ′|≫1/D (D is a high-energy cutoﬀ)it takes the form [15]G pp 0(t −t ′)→−πρT2ρJ lnD2.(6)For T t ≫1this reduces to the usual equilibrium form,γ∝J 1+1T ,with the logarithmic divergence cut oﬀonly by temperature.However,since in our case the Kondo coupling exists only for times t >0,the re-sult contains an additional cutoﬀdue to the ﬁnite time allowed for spin-ﬂip scattering.Formally,the ﬁnite time t since the onset of the Kondo coupling can be absorbed into an increase in the eﬀective temperature,T eﬀ=T¯h Γdot ∂ǫ,(8)where f (ǫ)is the Fermi function,and ¯h is explicitly in-cluded for clarity.If a periodic gate voltage is applied tothe dot,formula (8)is still valid if G is replaced by the time-averaged conductance G ,and ρdot (ǫ)is replaced by the average of the time-dependent spectral density ρdot (ǫ,t ) .Consider a periodic signal consisting of an “on”pulse of duration τon which brings the dot into the Kondo regime followed by an “oﬀ”pulse which moves it back out of the Kondo regime.During each on pulse,ρdot (ǫF ,t )will build up to a maximum at time τon and then rapidly decrease back to a low value during the oﬀpulse.The diﬀerential increase of conductance as the duration of the on100200300400τon [1/Γdot ]0.00.51.01.5d G i n t /d τo n [e 2/h ]T=0.04T=0.02T=0.01T=0.005T=0.0025ττon V (t)goffFIG.4.Solid curves:derivative of G int (in units of e 2/h )with respect to duration τon of “on”gate-voltage pulses,at various temperatures.G int is the conductance inte-grated over a full cycle of gate voltage.Dashed curve:−π dǫΓdot f ′(ǫ)ρdot (ǫ,t =τon )for T =0.0025.Inset:schematic periodic gate-voltage pulse train.The level energy is ǫdot =−2in the on state and ǫdot =−5in the oﬀstate.The duration of the oﬀperiod,τoﬀis long enough to allow transients from each on pulse to die out.pulse is increased will therefore reﬂect the magnitude of the spectral density near or at the Fermi energy at a timeτon following the shift into the Kondo regime.In Fig.(4),we have plotted the diﬀerential with respect to τon of the conductance,with a ﬁxed oﬀ-pulse duration τoﬀ.The conductance is integrated over the period,rather than time-averaged,to remove eﬀects due to the changing du-ration of the period,i.e.G int =(τon +τoﬀ) G .This measurable transport quantity provides a probe of the time-development of the Kondo resonance [18].In conclusion,we have analyzed the response of a quan-tum dot to a sudden shift of gate voltage which takes the dot into the regime of the Kondo eﬀect.The buildup of many-body correlations between the dot and the leads follows an uncertainty principle:at time t the Kondo res-onance is cut oﬀby an energy ∼1/t .Within perturba-tion theory in the Kondo coupling,we ﬁnd that the ﬁnite time t plays the role of an increased eﬀective tempera-ture T eﬀ=T/tanh(πT t/2).To experimentally probe the buildup of the Kondo resonance,we propose applying a train of square gate-voltage pulses to the dot.The deriva-tive of current with respect to duration of the “on”pulse accurately reproduces the time-dependent amplitude of the Kondo resonance.The work was supported in part by NSF grants DMR 95-21444(Rice)and DMR 97-08499(Rutgers).Work at BGU was supported by the The Israel Science Founda-tion -Centers of Excellence Program.One of us (MP)acknowledges the support of a Kreitman Fellowship.D Γdot /4,where 2D is the eﬀectivebandwidth.The calculations here used a parabolic band of total width 40Γdot .[11]A.-P.Jauho,N.S.Wingreen,and Y.Meir,Phys.Rev.B 50,5528(1994).[12]Our calculations are based on the approximation that the switching time,τs ,is exactly zero.In reality,τs is always a ﬁnite time.Our results are valid for ﬁnite τs as well,provided that t ≫τs .[13]J.R.Schrieﬀer and P.A.Wolﬀ,Phys.Rev.149,491(1966).[14]A.A.Abrikosov,Physics 2,5(1965).[15]G.Yuval,and P.W.Anderson,Phys.Rev.B 1,1522(1970).[16]By evaluating the conduction electron self-energy to or-der J 3,we have directly conﬁrmed the ∼1/t cutoﬀfor the Kondo peak in the spectral density.[17]Y.Meir and N.S.Wingreen,Phys.Rev.Lett.68,2512(1992).[18]The diﬀerence between the dashed and solid curves at small τon reﬂects the ﬁnite decay -time of the Kondo res-onance after the pulse is switched oﬀ.。

Electron-phonon coupling电子声子耦合

Cu(2)
0.3530 123.82 -35.22 -88.30 0.30
O(2)
0.3740 0.76 6.50 6.45 13.71
O(3)
0.3787 -8.77 7.91 0.75 -0.09
O(4)
0.1540 290.52 -75.75 -188.87 25.90
position [c] FHF [mRy / a.u.] FIBS [mRy / a.u.] Fcore[mRy / a.u.] F [mRy / a.u.]
A1g
Ba Cu(2) O(2)-O(3) O(2)+O(3) O(4)
B2g
Ba Cu(2) O(4) O(3) O(2)
B3g
Ba Cu(2) O(4) O(2) O(3)
Raman Active Phonons
Theory
Spectral density [10 sr ]
100 80 60 40 20 0 0 100 200 300 400
Phonons & electron-phonon coupling
Claudia Ambrosch-Draxl Department fü r Materialphysik, Montanunversitä t Leoben, Austria Institut fü r Physik, Universitä t Graz, Austria
3N degrees of freedom
Set of 3N coupled equations
The Harmonic Approximation
N atoms per unit cell
# displacements Total energy Forces

光电化学_电化学阻抗_界面电容_概述及解释说明

光电化学电化学阻抗界面电容概述及解释说明1. 引言1.1 概述光电化学（photocatalysis）是一种利用光能来驱动化学反应的重要技术，它在环境净化、光催化和能源转换等领域具有广泛应用。

光电化学通过在半导体材料中形成光生载流子对来实现电荷转移，从而引发电化学反应。

而电化学阻抗（electrochemical impedance）则是一种用于研究界面及材料性质的非常有效的表征手段。

它基于对交流信号施加于系统的响应进行分析，可以获取界面与溶液之间的传递特性信息。

界面电容（interface capacitance）作为电系中一个关键参数，常用于表征材料或界面在电场作用下储存电荷的能力。

1.2 文章结构本文首先对光电化学进行了定义和原理阐述，并概括了其主要的反应类型和应用领域。

随后，文章将详细介绍电化学阻抗以及其相关概念、测量原理和方法，并探讨了如何通过电化学阻抗谱分析来研究界面特性。

接着，我们将重点关注界面电容，解释其在电化学中的重要意义和作用，并探究界面电容受到的影响因素。

最后，本文将对整体内容进行总结，并展望光电化学、电化学阻抗和界面电容相关研究领域的未来发展方向，并提出建议。

1.3 目的本文旨在全面概述并解释光电化学、电化学阻抗和界面电容这三个关键概念及其应用。

通过对这些概念的介绍和解析，读者将能够深入了解光电化学反应的机制以及如何利用电化学阻抗和界面电容对材料或界面特性进行研究分析。

同时，本文还希望为相关领域的研究者提供展望与建议，促进该领域未来研究的进一步发展。

2. 光电化学2.1 定义及原理光电化学是研究光与物质之间相互作用和相互转换的科学领域。

在光电化学中，通过吸收光能激发分子或材料中的电荷，从而引发一系列电化学反应。

这些反应可以是光诱导的电荷转移、电解质溶液中的界面反应等。

在光电化学过程中，光激发了材料中的电子并使其跃迁到更高能级或被激发到半导体带隙中。

这些激发态的载流子（如电子-空穴对）可以在材料内部传输，并与周围所处的氧化还原体系进行反应。

Electron-Positron colliders

a r X i v :h e p -e x /0111070v 1 22 N o v 2001ELECTRON-POSITRON-COLLIDERSR.-D.HEUERInstitut f¨u r Experimentalphysik,Universit¨a t Hamburg,Luruper Chaussee 149,22761Hamburg GermanyE-mail:rolf-dieter.heuer@desy.deAn electron-positron linear collider in the energy range between 500and 1000GeV is of crucial importance to precisely test the Standard Model and to explore the physics beyond it.The physics program is complementary to that of the Large Hadron Collider.Some of the main physics goals and the expected accuracies of the anticipated measurements at such a linear collider are discussed.A short review of the diﬀerent collider designs presently under study is given including possible upgrade paths to the multi-TeV region.Finally a framework is presented within which the realisation of such a project could be achieved as a global international project.1IntroductionA coherent picture of matter and forces has emerged in the past decades through in-tensive theoretical and experimental studies.It is adequately described by the Standard Model of particle physics.In the last few years many aspects of the model have been stringently tested,some to the per-mille level,with e +e −,ep and p ¯p machines making com-plementary contributions,especially to the determination of the electroweak bining the results with neutrino scatter-ing data and low energy measurements,the experimental analysis is in excellent concor-dance with the electroweak part of the Stan-dard Model.Also the predictions of QCD have been thoroughly tested,examples being precise measurements of the strong coupling αs and probing the proton structure to the shortest possible distances.Despite these great successes there are many gaps in our understanding.The clearest one is the present lack of any direct evidence for the dynamics of electroweak symmetry breaking and the generation of the masses of gauge bosons and fermions.The Higgs mechanism which generates the masses of the fundamental particles in the Standard Model,has not been experimentally estab-lished though the indirect evidence from pre-cision measurements is very strong.Even ifsuccessfully completed,the Standard Model does not provide a comprehensive theory of matter.There is no explanation for the wide range of masses of the fermions,the grand uniﬁcation between the two gauge theories,electroweak and QCD,is not realised and gravity is not incorporated at the quantum level.Several alternative scenarios have been de-veloped for the physics which may emerge beyond the Standard Model as energies are increased.The Supersymmetric extension of the Standard Model provides a stable bridge from the presently explored energy scales up to the grand uniﬁcation scale.Alternatively,new strong interactions give rise to strong forces between W bosons at high energies.Quite general arguments suggest that such new phenomena must appear below a scale of approximately 3TeV.Extra space dimen-sions which alter the high energy behaviour in such a way that the energy scale of gravity is in the same order as the electroweak scale are another proposed alternative.There are two ways of exploring the new scales,through attaining the highest possible energy in a hadron collider and through high precision measurements at the energy fron-tier of lepton colliders.This article is based on the results ofmany workshops on physics and detector studies for linear colliders.Much more can be found in the respective publications1,2,3,4 and on the diﬀerent Web sites5,6,7,8.Many people have contributed to these studies and the references to their work can be found in the documents quoted above.2Complementarity of Lepton and Hadron MachinesIt is easier to accelerate protons to very high energies than leptons,but the detailed colli-sion process cannot be well controlled or se-lected.Electron-positron colliders oﬀer a well√deﬁned initial state.The collision energying generation of colliders.The physics case for such a machine will depend on the results from the LHC and the linear collider in the sub-TeV range.3Selected Physics TopicsIn this chapter,some of the main physics top-ics to be studied at a linear collider will bediscussed.Emphasis is given to the study of the Higgs mechanism in the Standard Model,the measurements of properties of su-persymmetric particles,and precision tests of the electroweak theory.More details about these topics as well as information about the numerous topics not presented here can be found in the physics books published in the studies of the physicspotential offuture lin-ear colliders 1,2,3,4.3.1Standard Model Higgs BosonThe main task of a linear electron-positron collider will be to establish experimentally the Higgs mechanism as the mechanism for generating the masses of fundamental parti-cles:•The Higgs boson must be discovered.•The couplings of the Higgs boson to gauge bosons and to fermions must be proven to increase with their masses.•The Higgs potential which generates the non-zero ﬁeld in the vacuum must be reconstructed by determining the Higgs self-coupling.•The quantum numbers (J P C =0++)must be conﬁrmed.The main production mechanisms for Higgs bosons in e +e −collisions are Higgs-strahlung e +e −→HZ and WW-fusion e +e −→νe ¯νe H ,and the corresponding cross-sections as a function of M H are depicted in ﬁgure 2for three diﬀerent centre of mass en-ergies.With an integrated luminosity of 500Figure 2.The Higgs-strahlung and WW fusion pro-duction cross-sections as a function of M H for diﬀer-ent√sof about 800GeV;for 1000fb −1an accuracyof 6%can be expected.The Higgs boson quantum numbers can be determined through the rise of the cross sec-tion close to the production threshold and through the angular distributions of the H and Z bosons in the continuum.Recoil Mass [GeV ]N u m b e r o f E v e n t s / 1.5 G e VFigure 3.The µ+µ−recoil mass distribution in theprocess e +e −→HZ →µ+µ−for M H =120GeV,500fb −1at√2of the self potential of the Higgs ﬁeld V =λ(φ2−14λH4.The trilinearHiggs coupling λHHH =6λv can be mea-sured directly in the double Higgs-strahlung process e +e −→HHZ →q ¯q b ¯bb ¯b .The ﬁ-nal state contains six partons resulting in a rather complicated experimental signature with six jets,a challenging task calling for ex-cellent granularity of the tracking device and the calorimeter 9.Despite the low cross sec-tion of the order of 0.2fb for M H =120GeV at√s =500GeV with an integrated luminosity of 1ab −1as shown in ﬁgure 6.Measurements of Higgs boson properties and their anticipated accuracies are sum-marised in table 1.In summary,the Higgs mechanism can be established in an unambiguous way at a high luminosity electron-positron collider with a centre-of-mass energy up to around one TeV as the mechanism responsible for the sponta-neous symmetry breaking of the electroweak interactions.3.2Supersymmetric ParticlesSupersymmetry (SUSY)is considered the most attractive extension of the Standardg c /g c (SM)g b /g b (S M )0.80.850.90.9511.051.11.151.2Figure 5.Higgs coupling determination:The con-tours for g b vs.g c for a 120GeV Higgs boson normalised to their Standard Model expectations as measured with 500fb −1.Model,which cannot be the ultimate the-ory for many reasons.The most impor-tant feature of SUSY is that it can explain the hierarchy between the electroweak scale of ≈100GeV,responsible for the W and Z masses,and the Planck scale M P l ≃1019GeV.When embedded in a grand-uniﬁed the-ory,it makes a very precise prediction of the electroweak mixing angle sin 2θW in excellent concordance with the precision electroweak measurement.In the following,only the min-imal supersymmetric extension to the Stan-dard Model (MSSM)will be considered and measurements of the properties of the super-symmetric particles will be discussed.Stud-ies of the supersymmetric Higgs sector can be found elsewhere 1,2,3,4.In addition to the particles of the Stan-dard Model,the MSSM contains their su-persymmetric partners:sleptons ˜l ±,˜νl (l =e,µ,τ),squarks ˜q ,and gauginos ˜g ,˜χ±,˜χ0.In the MSSM the multiplicative quantum num-ber R-parity is conserved,R p =+1for par-10012014016018000.20.10.3M H [GeV ]SM Double Higgs-strahlung: e + e - → ZHH σ [fb ]√s = 800 GeV√s = 500 GeVFigure 6.The cross-section for doubleHiggs-strahlung in the Standard Model at√120GeVmass 0.05%spin yes CPyes6%g HZZ 1%g HW W 2%g Hbb 2%g Hcc 10%g Hττ5%g Htt 6%λHHH∼30%ticles and R p =−1for sparticles.Spar-ticles are therefore produced in pairs and they eventually decay into the lightest spar-ticle which has to be stable.As an example,smuons are produced and decay through theprocess e +e −→˜µ+˜µ−→µ+µ−χ01χ01with χ01as the lightest sparticle being stable and,therefore,escaping detection.The mass scale of sparticles is only vaguely known.In most scenarios some spar-ticles,in particular charginos and neutrali-nos,are expected to lie in the energy region accessible by the next generation of e +e −200400600800Figure 7.Examples of mass spectra in mSUGRA,GMSB and AMSB models.colliders alsosupported bythe recentmea-surement of (g −2)µ10.Examples of massspectra for three SUSY breaking mechanisms (mSUGRA,GMSB,AMSB)are given in ﬁg-ure 7.The most fundamental problem of super-symmetric theories is how SUSY is broken and in which way this breaking is communi-cated to the particles.Several scenarios have been proposed in which the mass spectra are generally quite diﬀerent as illustrated in ﬁg-ure 7.High precision measurements of the particle properties are therefore expected to distinguish between some of these scenarios.The study and exploration of Supersymmetry will proceed in the following steps:•Reconstruction of the kinematically ac-cessible spectrum of sparticles and the measurement of their properties,masses and quantum numbers•Extraction of the basic low-energy pa-rameters such as mass parameters,cou-plings,and mixings•Analysis of the breaking mechanism and reconstruction of the underlying theory.While it is unlikely that the complete spectrum of sparticles will be accessible at acollider with√Figure 9.Cross section near threshold for the processe +e −→˜χ+1˜χ−1,10fb−1per point.approach,the measured electroweak scaleSUSY parameters are extrapolated to high energies using these RGE’s.Due to the high precision of the measured input variables,only possible at the linear collider,an accurate test can be performed at which energy scale certain parameters be-come equal.Most interesting,the assump-tion of grand uniﬁcation of forces requires the gaugino mass parameters M 1,M 2,M 3to meet at the GUT scale (ﬁgure 10(left)).Diﬀerent SUSY breaking mechanisms predict diﬀerent uniﬁcation patterns of the sfermion mass parameters at high energy.With the high accuracy of the linear collider measure-ments these models can be distinguished as shown in ﬁgure 10for the case of mSUGRA (middle)and GMSB (right).In summary,the high precision studies of supersymmetric particles and their properties can open a window to energy scales far above the scales reachable with future accelerators,possibly towards the Planck scale where grav-ity becomes important.3.3Precision MeasurementsThe primary goal of precision measurements of gauge boson properties is to establish the non-abelian nature of electroweak interac-tions.The gauge symmetries of the Stan-dard Model determine the form and the strength of the self-interactions of the elec-troweak bosons,the triple couplings W W γand W W Z and the quartic couplings.Devi-ations from the Standard Model expectations for these couplings could be expected in sev-eral scenarios,for example in models where there exists no light Higgs boson and where the W and Z bosons are generated dynam-ically and interact strongly at high scales.Also for the extrapolation of couplings to high scales to test theories of grand uniﬁ-cation such high precision measurements are mandatory.For the study of the couplings between gauge bosons the best precision is reached at the highest possible centre of mass energies.These couplings are especially sen-sitive to models of strong electroweak sym-metry breaking.W bosons are produced either in pairs,e +e −→W +W −or singly,e +e −→W eνwith both processes being sensitive to the triple gauge couplings.In general the total errors estimated on the anomalous couplings are in the range of few ×10−4.Figure 11com-pares the precision obtainable for ∆κγand ∆λγat diﬀerent machines.The measurements at a linear collider are sensitive to strong symmetry breaking be-yond Λof the order of 5TeV,to be com-pared with the electroweak symmetry break-ing scale ΛEW SB =4πv ≈3TeV.One of the most sensitive quantities to loop corrections from the Higgs boson is the eﬀective weak mixing angle in Z boson de-cays.By operating the collider at ener-gies close to the Z -pole with high luminos-ity (GigaZ)to collect at least 109Z bosons in particular the accuracy of the measure-Figure 10.Extrapolation of SUSY parameters measured at the electroweak scale to high energies.10-410-310-2∆κγLEP TEV LHCTESLA TESLA 50080010-410-310-2∆λγLEP TEV LHCTESLA TESLA500800Figure parison of constraints on the anomalous couplings ∆κγand ∆λγat diﬀerent machinesment of sin 2θleff can be improved by one or-der of magnitude wrt.the precision obtained today 11.With both electron and positronbeams longitudinally polarised,sin 2θleff can be determined most accurately by measur-ing the left-right asymmetry A LR =A e =2v e a e /(v 2e +a 2e )with v e (a e )being the vec-tor (axialvector)couplings of the Z boson tothe electron and v e /a e =1-4sin 2θleff for pure Z exchange.Particularly demanding is the precision of 2×10−4with which the po-larisation needs to be known to match the statistical accuracy.An error in the weakmixing angle of ∆sin 2θleff =0.000013can be expected.Together with an improved de-termination of the mass of the W boson toa precision of some 6MeV through a scan of the W W production threshold and with the measurements obtained at high energy run-ning of the collider this will allow many high precision tests of the Standard Model at the loop level.As an example,ﬁgure 12shows the variation of the ﬁt χ2to the electroweak measurements as a function of M H for the present data and for the data expected at a linear collider.The mass of the Higgs bo-son can indirectly be constraint at a level of 5%.Comparing this prediction with the di-rect measurement of M H consistency tests of the Standard Model can be performed at the quantum level or to measure free parameters in extensions of the Standard Model.This is5101520101032000LCm hχ2Figure 12.∆χ2as a function of the Higgs boson mass for the electroweak precision data today (2000)and after GigaZ running (LC).of particular importance if M H >200GeV in contradiction to the current electroweak mea-surements.In summary,there is strong evidence for new phenomena at the TeV energy scale.Only the precision exploration at the linear collider will allow,together with the results obtained at the Large Hadron Collider,the understanding of the underlying physics and will open a new window beyond the centre-of-mass energies reachable.Whatever sce-nario is realized in nature,the linear collider will add crucial information beyond the LHC.There is global consensus in the high energy physics community that the next accelera-tor based project needs to be an electron-positron linear collider with a centre-of-mass energy of at least 500GeV.4Electron-Positron Linear CollidersThe feasibility of a linear collider has been successfully demonstrated by the operationof the SLAC Linear Collider,SLC.How-ever,aiming at centre-of-mass energies at the TeV scale with luminosities of the order of 1034cm −2s −1requires at least two orders of magnitude higher beam power and two orders of magnitude smaller beam sizes at the inter-action point.Over the past decade,several groups worldwide have been pursuing diﬀer-ent linear collider designs for the centre-of-mass energy range up to around one TeV as well as for the multi-TeV range.Excel-lent progress has been achieved at various test facilities worldwide in international col-laborations on crucial aspects of the collider designs.At the Accelerator Test Facility at KEK 12,emittances within a factor two of the damping ring design have been achieved.At the Final Focus Test Beam at SLAC 13de-magniﬁcation of the beams has been proven;the measured spot sizes are well in agreement with the theoretically expected values.The commissioning and operation of the TESLA Test Facility at DESY 14has demonstrated the feasibility of the TESLA technology.In the following,a short review of the diﬀerent approaches is given.4.1TeV rangeThree design studies are presently pursued:JLC 15,NLC 16and TESLA 17,centred around KEK,SLAC and DESY,respectively.Details about the design,the status of de-velopment and the individual test facilities can be found in the above quoted references as well as in the status reports presented at LCWS200018,19,20.A comprehensive sum-mary of the present status can be found in the Snowmass Accelerator R&D Report 21,here only a short discussion of the main features and diﬀerences of the three approaches will be given with emphasis on luminosity and en-ergy reach.One key parameter for performing the physics program at a collider is the centre-of-mass energy achievable.The energy reachof a collider with a given linac length and a certain cavityﬁlling factor is determined by the gradient achievable with the cavity tech-nology chosen.For normalconducting cavi-ties the maximum achievable gradient scales roughly proportional to the RF frequency used,for superconducting Niobium cavities, the fundamental limit today is around55 MV/m.The second key parameter for the physicsprogram is the luminosity L,given byL=n b N2e f rep(σ∗x+σ∗y)2.Choos-ing aﬂat beam size(σ∗x≫σ∗y)at the inter-action point,δE becomes independent of the vertical beam size and the luminosity can be increased by reducingσ∗y as much as possi-ble.Sinceσ∗y∝sn b N e f rep=ηP AC is obtained from themains power P AC with an eﬃciency η.Equation(1)can then be rewritten asL∝ηP AC s ǫy(2)High luminosity therefore requires high ef-ﬁciencyηand high beam quality with low emittanceǫy and low emittance dilution ∆ǫ/ǫ∝f6RF,which is largely determined by the RF frequency f RF of the chosen technol-ogy.The fundamental diﬀerence between the three designs is the choice of technology for the accelerating structures.The design of NLC is based on normalconducting cavities using f RF of11.4GHz(X-band),for JLC two options,X-band or C-band(5.7GHz)are pursued.The TESLA concept,developed by the TESLA collaboration,is using supercon-ducting cavities(1.3GHz).As an example for a linear collider facility,ﬁgure13shows the schematic layout of TESLA.Figure13.Schematic layout of TESLATable2compares some key parameters for the diﬀerent technologies at√Figure 14.Evolution of superconducting cavity per-formance.The average gradient achieved with TESLA 9-cell cavities produced in industry (ﬁrst test,no additional processing)is shown as dots.with N b bunches,the time ∆T b between bunches within a train which allows head on crossing of the bunches for TESLA but requires a crossing angle for the other de-signs.The design luminosity L ,beam power P beam and the required mains power P AC il-lustrate that for a given mains power the su-perconducting technology delivers higher lu-minosity.On the other hand the lower gradi-ent G acc requires a longer linac for the samecentre-of-massenergy reach.As can be seen from table 2the X-band machines call for a beam loaded (unloaded)gradient of some 50(70)MV/m for√s =500GeV,a gradient which is mean-while routinely achieved for cavities fabri-cated in industry as illustrated in ﬁgure 14.Table 2also contains the presently planned length of the facilities 17,16,22,23.AnFigure 15.Excitation curves of three electropolished single-cell cavities.Gradients well above 35MV/m are reached.upgrade in energy up to around one TeV seems possible for all designs.In the NLC case,more cavities would be installed within the existing tunnel,in the JLC case,the tunnel length would have to be increased to house more cavities.In the TESLA case,a gradient of around 35MV/m is neededto reach√Table parison of some crucial parameters at 500GeV for the diﬀerent technologies under study,see text for details.NLCJLC-C51502820190337 1.4head on angle 20.7σ∗x/y [nm ]245/2.7318/4.3δE [%]4.73.93.42.64P beam [MW ]13.212.6P AC (linacs )[MW ]13222023.550.23316s of 3TeV,usinghigh frequency (30GHz)normalcon-ducting structures operating at very high ac-celerating ﬁelds (150MV/m).The present design calls for bunch separations of .67ns,a vertical spotsize of 1nm and beamstrahlung δE of 30%.For this promising concept a new test facility is under construction at CERN which should allow tests with full gradient starting in 2005.5RealisationThe new generation of high energy colliders most likely exceeds the resources of a coun-try or even a region.There is general consen-sus that the realisation has to be done in an international,interregional framework.One such framework,the so called Global Accel-erator Network (GAN),has been proposed to ICFA in March 2000.A short discussion of the principle considerations will be presented here,more details can be found in ref.25.The GAN is a global collaboration of lab-oratories and institutes in order to design,construct,commission,operate and main-tain a large accelerator facility.The model is based on the experience of large experi-mental collaborations,particularly in particle physics.Some key elements are listed below:•it is not an international permanent in-stitution,but an international project of limited duration;•the facility would be the common prop-erty of the participating countries;•there are well deﬁned roles and obliga-tions of all partners;•partners contribute through components or subsystems;•design,construction and testing of com-ponents is done in participating institu-tions;•maintenance and running of the accel-erator would be done to a large extent from the participating institutions.The GAN would make best use of world-wide competence,ideas and resources,create a visible presence of activities in all partici-pating countries and would,hopefully,make the site selection less controversial.study general considerations of implementing a GAN and to study the technical considera-tions and inﬂuence on the design and cost of the accelerator.The reports of these working groups can be found on the web26.Their overall conclusion is that a GAN can be a fea-sible way to build and operate a new global accelerator,although many details still need to be clariﬁed.6SummaryThere is global consensus about the next ac-celerator based project in particle physics.It has to be an electron-positron linear collider with an initial energy reach of some500GeV with the potential of an upgrade in centre-of-mass energy.The physics case is excellent, only a few highlights could be presented here. There is also global consensus that concur-rent operation with LHC is needed and fruit-ful.Therefore,a timely realisation is manda-tory.The technical realisation of a linear col-lider is now feasible,several technologies are either ripe or will be ripe soon.A fast consen-sus in the community about the technology is as a global project with the highest possible luminosity and a clear upgrade potential be-yond500GeV.AcknowledgmentsThe author would like to express his grati-tude to all people who have contributed to the studies of future electron-positron linear colliders from the machine design to physics and detector studies.Special thanks go to the organisers and their team for a very well or-ganised,inspiring conference as well as for the competent technical help in preparing this presentation.References1.J.A.Aguilar-Saavedra et al,TESLATechnical Design Report,Part III,Physics at an e+e−Linear Collider,DESY2001-011,ECFA2001-209,hep-ph/0106315.2.T.Abe et al,Linear Collider Physics Re-source Book for Snowmass2001,BNL-52627,CLNS01/1729,FERMILAB-Pub-01/058-E,LBNL-47813,SLAC-R-570,UCRL-ID-143810-DR,LC-REV-2001-074-US,hep-ex/0106055-583.K.Abe et al,Particle Physics Exper-iments at JLC,KEK-Report2001-11, hep-ph/0109166.4.Proceedings of LCWS,Physics and Ex-periments with Future Linear Colliders, eds A.Para,H.E.Fisk,(AIP Conf.Proc.,Vol578,2001).5.Worldwide Study of the Physics and De-tectors for Future e+e−Colliders/lc/6.ACFA Joint Linear Collider Physics andDetector Working Grouphttp://acfahep.kek.jp/7.2nd Joint ECFA/DESY Studyon Physics and Detectors for a Linear Electron-Positron Colliderhttp://www.desy.de/conferences/ecfa-desy-lc98.html8.A Study of the Physics and Detectors forFuture Linear e+e−Colliders:American Activities/lc/ameri-ca.html9.G.Alexander et al,TESLA TechnicalDesign Report,Part IV,A Detector for TESLA,DESY2001-011,ECFA2001-209.10.H.N.Brown et al.[Muon g-2Collabo-ration],Phys.Rev.Lett.86(2001)222711.J.Drees,these proceedings12.E.Hinode et al,eds.,KEK Internal95-4,1995,eds J.Urakawa and M.Yoshioka, Proceedings of the SLAC/KEK Linear Collider Workshop on Damping Ring, KEK92-6,199213.The FFTB Collaboration:BINP(Novosibirsk/Protvino),DESY, FNAL,KEK,LAL(Orsay),MPI Mu-nich,Rochester,and SLAC14.Proposal for a TESLA Test Facility,DESY TESLA-93-01,199215.KEK-Report97-1,1997.16.Zeroth Order Design Report for theNext Linear Collider,SLAC Report474,1996.2001Report on the Next Linear Collider,Fermilab-Conf-01-075-E,LBNL-47935,SLAC-R-571,UCRL-ID-14407717.J.Andruszkow et al,TESLA TechnicalDesign Report,Part II,The Accelerator, DESY2001-011,ECFA2001-20918.O.Napoly,TESLA Linear Collider:Sta-tus Report,in ref419.T.O.Raubenheimer,Progress in theNext Linear Collider Design,in ref4 20.Y.H.Chin et al Status of JLC Accelera-tor Development,in ref421.A.Chao et al,2001Snowmass Accelera-tor R&D Report,http://www.hep.anl.gov/pvs/dpb/Snowmass.pdf22.Y.H.Chin,private communication23.H.Matsumoto,T.Shintake,private com-munication24.I.Wilson,A Multi-TeV Compact e+e−Linear Collider,in ref425.F.Richard et al,TESLA Technical De-sign Report,Part I,Executive Summary, DESY2001-011,ECFA2001-209,hep-ph/0106314.26./directorate/icfa/icfa reports.html。

拉曼光谱测量钙钛矿电声耦合强度

拉曼光谱测量钙钛矿电声耦合强度1.拉曼光谱是一种用于分析晶体材料结构和性质的强大技术。

Raman spectroscopy is a powerful technique for analyzing the structure and properties of crystalline materials.2.钙钛矿是一类具有重要电声耦合特性的材料。

Perovskite is a type of material with important electroacoustic coupling properties.3.通过拉曼光谱，可以了解钙钛矿中电声耦合的强度和机制。

Raman spectroscopy can be used to understand the strength and mechanism of electroacoustic coupling in perovskite.4.钙钛矿的电声耦合特性对于光伏和光电器件的性能至关重要。

The electroacoustic coupling properties of perovskite are crucial for the performance of photovoltaic and optoelectronic devices.5.拉曼光谱可以提供关于晶体结构、相变和电子结构的丰富信息。

Raman spectroscopy can provide rich information about crystal structure, phase transitions, and electronic structure.6.钙钛矿材料的电声耦合性质直接影响着其光电器件的效率和稳定性。

The electroacoustic coupling properties of perovskite materials directly affect the efficiency and stability oftheir optoelectronic devices.7.拉曼光谱测量可以帮助科学家们深入了解钙钛矿材料的微观特性。

增强体表面改性在高导热金属基复合材料中的应用

第15卷第2期2024年4月有色金属科学与工程Nonferrous Metals Science and EngineeringVol.15，No.2Apr. 2024增强体表面改性在高导热金属基复合材料中的应用蔡志勇1，2，3，文璟1，王日初*1，2，3，彭超群1，2（1.中南大学材料科学与工程学院，长沙 410083； 2.湖南省电子封装与先进功能材料重点实验室，长沙 410083；3.中南大学轻质高强结构材料重点实验室，长沙410083）摘要：随着电子技术的高速发展和电子器件的更新换代，电子封装材料的性能需求越来越高。

金属基复合材料，尤其是铝基和铜基复合材料具有高导热、低膨胀、高稳定性等特点，是具有广阔应用前景的电子封装材料。

然而，金刚石、石墨烯、硅等增强体与基体的润湿性差，或者在高温下与基体发生有害的界面反应，限制了此类高导热金属基复合材料的开发和应用。

本文简述了金属基复合材料的界面研究进展，结合影响金属基复合材料界面结合的因素，提出了几种改善界面结合的方法。

增强体表面改性是改善金属基复合材料界面的重要途径之一，常用工艺有磁控溅射法、化学气相沉积法、溶胶凝胶法、化学镀法等；最后，对增强体表面改性在高热导金属基复合材料中的应用进行分析和展望。

关键词：电子封装材料；金属基复合材料；铝基复合材料；铜基复合材料；增强体；界面反应；表面改性中图分类号：TB333 文献标志码：AApplication of surface modification of reinforcing phase in metal matrix composites with high thermal conductivityCAI Zhiyong 1, 2, 3, WEN Jing 1, WANG Richu *1, 2, 3, PENG Chaoqun 1, 2（1. School of Materials Science and Engineering ， Central South University ， Changsha 410083， China ； 2. Key Laboratory of Electronic Packaging and Advanced Functional Materials of Hunan Province ， Changsha 410083， China ； 3. National Key Laboratory of Science andTechnology on High-strength Structural Materials ， Central South University ， Changsha 410083， China ）Abstract: With the rapid development of electronic technology and the upgrading of electronic devices, the requirement for electronic packaging materials is getting higher than before. Metal matrix composites, especially aluminum and copper matrix composites have the characteristics of high thermal conductivity, low expansion, and high stability, which are electronic packaging materials with broad application prospects. However, diamond, graphene, silicon, and other reinforcements have poor wettability with the matrix, or have harmful interface reaction with the matrix at high temperature, which limits the development and application of metal matrix composites with the high thermal conductivity. This paper briefly described the research progress of interface of metal matrix composites, and proposed several methods to improve the interface bonding based on the factors that affect the interface bonding of metal matrix composites. Surface modification of reinforcement is one of the most important收稿日期：2023-02-01；修回日期：2023-04-20基金项目：国家自然科学基金资助项目（52274369）；中国博士后科学基金项目（2018M632986）；湖南省自然科学基金项目（2019JJ50766）；轻质高强结构材料国防重点实验室开放基金资助项目（JCKY201851）通信作者：王日初（1965—　），博士，教授，主要从事材料科学与工程方面的教学及科研工作。

物理所揭示永磁薄膜材料中拓扑增强的室温大反常能斯特效应

物理所揭示永磁薄膜材料中拓扑增强的室温大反常能斯特效应1. 引言1.1 概述在当前材料科学领域中，拓扑量子相的研究备受关注。

特别是在永磁薄膜材料中，最近的研究表明存在一种称为拓扑增强的室温大反常能斯特效应。

这种现象引发了广泛的兴趣，并被认为具有重要的科学和技术应用前景。

本文将详细探讨这种拓扑增强效应在永磁薄膜材料中的观测、理论模型以及实验结果分析等方面的内容。

1.2 文章结构本文首先介绍了永磁薄膜材料的基本概念和特性，包括其组成、结构和性质等相关内容。

随后，对拓扑增强效应背景和意义进行了详细阐述，包括其在材料物性研究和新型器件设计方面带来的潜在影响。

接着，我们将继续探讨室温大反常能斯特效应所涉及到的观测现象和理论模型，并对相关实验结果进行详细分析和讨论。

最后，本文还将探讨该效应的应用前景和挑战，包括可能的应用领域以及面临的加工、稳定性等问题，并提出未来进一步研究方向。

1.3 目的本文的目的是系统梳理永磁薄膜材料中拓扑增强的室温大反常能斯特效应相关信息，并对其进行深入分析和探讨。

通过综合评述研究成果，我们旨在进一步揭示该效应在材料科学和器件设计方面的潜力，并为其未来发展提出建议。

同时，我们也希望为物理学家和材料科学家提供一个全面了解这一领域最新进展的参考资料。

2. 永磁薄膜材料中拓扑增强的室温大反常能斯特效应2.1 永磁薄膜材料的介绍永磁薄膜材料是一种具有自发磁化的材料，在室温下能够保持稳定的磁性。

这种材料通常由具有高自旋轨道耦合、孤立或局域自旋态的过渡金属元素组成，如铁、镍和钴等。

永磁材料具有重要的应用价值，例如在信息存储、传感器和能量转换等领域。

2.2 拓扑增强效应的背景和意义拓扑增强效应是指通过调控晶体结构或微观纳米尺度中的电子结构来实现特殊物理现象或性质。

拓扑能斯特效应是指在材料中存在特殊电子态，这些态在系统边界产生非平凡的表面态或边界态，并且这些边界态对电荷输运和能量传递具有重要影响。

近年来，拓扑材料相关领域取得了很多重要突破，吸引了广泛的研究兴趣。

硅片上技术的太赫兹拓扑绝缘体

硅片上技术的太赫兹拓扑绝缘体1.太赫兹波段是一种处于电磁波谱中的特定频率范围。

The terahertz band is a specific frequency range in the electromagnetic spectrum.2.太赫兹波段的应用范围广泛，包括通信、成像和材料科学等领域。

The terahertz band has a wide range of applications, including communication, imaging, and material science.3.在硅片上实现太赫兹技术是一种新的研究方向。

Implementing terahertz technology on silicon wafers is a new research direction.4.太赫兹技术能够在纳米尺度下实现高精度的材料成像。

Terahertz technology can achieve high-precision material imaging at the nanoscale.5.太赫兹拓扑绝缘体是一种具有特殊电子结构的材料。

Terahertz topological insulator is a material with a special electronic structure.6.这种特殊电子结构使得太赫兹拓扑绝缘体具有低能耗和高效率的特性。

This special electronic structure enables terahertz topological insulators to have low energy consumption and high efficiency.7.太赫兹拓扑绝缘体的研究有望带来下一代电子器件的革命。

The research of terahertz topological insulators is expected to bring about a revolution in the next generation of electronic devices.8.硅片作为基底材料能够提供良好的物理支持和热导性能。

高迁移率有机半导体材料与器件的研究 2023国家自然科学奖

高迁移率有机半导体材料与器件的研究2023国家自然科学奖1. 引言1.1 概述随着信息技术的迅速发展，有机半导体材料作为一种新型材料，引起了广泛的关注和研究。

高迁移率有机半导体材料是近年来研究的热点之一，其在电子器件领域具有广阔的应用前景。

本文将重点探讨高迁移率有机半导体材料与器件的研究，并对2023国家自然科学奖对该领域研究的支持和影响进行分析。

1.2 研究背景传统的硅基半导体材料具有成熟稳定的性能和制备工艺，但在柔性电子、可穿戴设备等领域存在局限性。

相比之下，有机半导体材料具有轻质、柔性可弯曲、低成本等优势，因此被认为是未来电子器件发展的重要方向之一。

然而，传统有机半导体材料通常具有较低的载流子迁移率，限制了其在高性能电子器件中的应用。

为了解决这个问题，高迁移率有机半导体材料被提出并广泛研究，以期实现高性能有机器件的制备。

1.3 目的和意义本文旨在系统地介绍高迁移率有机半导体材料及其相关器件的研究进展，并探讨其在电子器件领域的应用前景。

同时，文章将对2023年国家自然科学奖对于该领域研究的支持和影响进行分析，以便更好地了解该领域的最新发展和未来趋势。

相信通过本文的阐述，可以进一步推动高迁移率有机半导体材料与器件的研究，在相关领域取得更多重要突破，并为推动我国信息技术产业发展贡献力量。

以上是“1. 引言”部分内容，接下来将详细阐述“2. 高迁移率有机半导体材料的特点与应用”的相关内容。

2. 高迁移率有机半导体材料的特点与应用2.1 高迁移率有机半导体材料的概念高迁移率有机半导体材料是一类具有高电子或空穴迁移率的有机化合物。

相比传统无机半导体材料，高迁移率有机半导体材料在电子输运速度、可加工性和柔性等方面具备显著优势。

这些材料通常由有机分子或聚合物构成，其分子结构可以被调控和设计以实现更高的载流子迁移率。

2.2 材料特性与性能分析高迁移率有机半导体材料展示了许多独特的特性和优良的性能，使其在各种领域中拥有广泛的应用前景。

基于碳纳米管薄膜的表面等离子激元透射特性

Transmission Properties of Surface Plasmon Polaritons Based on Carbon Nanotube FilmsWANG Yue1,2,WANG Xuan1,HE Xun-jun2,LI Shu2,LI Long-wei3(1.Key Laboratory of Engineering Dielectrics and Its Application,Ministry of Education,Harbin University of Science and Technology,Harbin150040,China)(2.Department of Electronic Science and Technology,Harbin University of Science andTechnology,Harbin150040,China)(3.Key Laboratory for the Physics&Chemistry of Nano Devices,Peking University,Beijing100083,China)Abstract:The finite integration technique was employed to evaluate enhanced transmission characteristics at terahertz wavelength by means of a bulls-eyes structure with periodic grooves based on effective carbon nanotube film using.The effect of the number of grooves,groove width,groove depth,and the conductivity of material on the enhanced transmission of terahertz waves was investigated.The results indicated that by placing the grooves at the near field of the aperture,strongly localized electromagnetic fields are effectively coupled to the aperture with a radius that is200times smaller than the resonance wavelength,and that2.4fold enhancement factor could be obtained with a subwavelength bull-eyes surrounded by three concentric periodic grooves.The results were attributed that the high transmission form an aperture with grooves is assisted by coupling to the surface plasmons.Keywords:surface plasmon polaritions;carbon nanotube film;enhanced transmission基于碳纳米管薄膜的表面等离子激元透射特性王1,2,王暄1,贺训军2,李述2,李龙威3玥(1.哈尔滨理工大学教育部工程电介质与应用重点实验室,黑龙江哈尔滨150040)(2.哈尔滨理工大学电子科学与技术系,黑龙江哈尔滨150040)(3.北京大学纳米器件物理与化学重点实验室,北京100083)摘要：利用有限积分技术研究了碳纳米管薄膜微结构在太赫兹波段的增强透射特性，研究了微结构的数目、宽度、深度以及材料电导率变化时对透射特性影响规律，结果表明，在微结构孔周围设计比共振波长小200倍的环形槽会产生局域化强场，增强因子能达到2.4，这种增强机制来源于微结构与表面波的强耦合作用。

核磁共振中常用的英文缩写和中文名称

NMR 中常用的英文缩写和中文名称收集了一些NMR 中常用的英文缩写,译出其中文名称,供初学者参考,不妥之处请指出,也请继续添加.相关附件NMR 中常用的英文缩写和中文名称APT Attached Proton Test 质子连接实验ASIS Aromatic Solvent Induced Shift 芳香溶剂诱导位移BBDR Broad Band Double Resonance 宽带双共振BIRD Bilinear Rotation Decoupling 双线性旋转去偶(脉冲)COLOC Correlated Spectroscopy for Long Range Coupling 远程偶合相关谱COSY ( Homonuclear chemical shift ) COrrelation SpectroscopY (同核化学位移)相关谱CP Cross Polarization 交叉极化CP/MAS Cross Polarization / Magic Angle Spinning 交叉极化魔角自旋CSA Chemical Shift Anisotropy 化学位移各向异性CSCM Chemical Shift Correlation Map 化学位移相关图CW continuous wave 连续波DD Dipole-Dipole 偶极-偶极DECSY Double-quantum Echo Correlated Spectroscopy 双量子回波相关谱DEPT Distortionless Enhancement by Polarization Transfer 无畸变极化转移增强2DFTS two Dimensional FT Spectroscopy 二维傅立叶变换谱DNMR Dynamic NMR 动态NMRDNP Dynamic Nuclear Polarization 动态核极化DQ(C) Double Quantum (Coherence) 双量子(相干)DQD Digital Quadrature Detection 数字正交检测DQF Double Quantum Filter 双量子滤波DQF-COSY Double Quantum Filtered COSY 双量子滤波COSYDRDS Double Resonance Difference Spectroscopy 双共振差谱EXSY Exchange Spectroscopy 交换谱FFT Fast Fourier Transformation 快速傅立叶变换FID Free Induction Decay 自由诱导衰减H,C-COSY 1H,13C chemical-shift COrrelation SpectroscopY 1H,13C 化学位移相关谱H,X-COSY 1H,X-nucleus chemical-shift COrrelation SpectroscopY 1H,X- 核化学位移相关谱HETCOR Heteronuclear Correlation Spectroscopy 异核相关谱HMBC Heteronuclear Multiple-Bond Correlation 异核多键相关HMQC Heteronuclear Multiple Quantum Coherence 异核多量子相干HOESY Heteronuclear Overhauser Effect Spectroscopy 异核Overhause 效应谱HOHAHA Homonuclear Hartmann-Hahn spectroscopy 同核Hartmann-Hahn 谱HR High Resolution 高分辨HSQC Heteronuclear Single Quantum Coherence 异核单量子相干INADEQUATE Incredible Natural Abundance Double Quantum Transfer Experiment 稀核双量子转移实验（简称双量子实验，或双量子谱）INDOR Internuclear Double Resonance 核间双共振INEPT Insensitive Nuclei Enhanced by Polarization 非灵敏核极化转移增强INVERSE H,X correlation via 1H detection 检测1H 的H,X 核相关IR Inversion-Recovery 反（翻）转回复JRES J-resolved spectroscopy J-分解谱LIS Lanthanide （chemical shift reagent ） Induced Shift 镧系（化学位移试剂）诱导位移LSR Lanthanide Shift Reagent 镧系位移试剂MAS Magic-Angle Spinning 魔角自旋MQ（C）Multiple-Quantum （ Coherence ）多量子（相干）MQF Multiple-Quantum Filter 多量子滤波MQMAS Multiple-Quantum Magic-Angle Spinning 多量子魔角自旋MQS Multi Quantum Spectroscopy 多量子谱NMR Nuclear Magnetic Resonance 核磁共振NOE Nuclear Overhauser Effect 核Overhauser 效应（NOE）NOESY Nuclear Overhauser Effect Spectroscopy 二维NOE 谱NQR Nuclear Quadrupole Resonance 核四极共振PFG Pulsed Gradient Field 脉冲梯度场PGSE Pulsed Gradient Spin Echo 脉冲梯度自旋回波PRFT Partially Relaxed Fourier Transform 部分弛豫傅立叶变换PSD Phase-sensitive Detection 相敏检测PW Pulse Width 脉宽RCT Relayed Coherence Transfer 接力相干转移RECSY Multistep Relayed Coherence Spectroscopy 多步接力相干谱REDOR Rotational Echo Double Resonance 旋转回波双共振RELAY Relayed Correlation Spectroscopy 接力相关谱RF Radio Frequency 射频ROESY Rotating Frame Overhauser Effect Spectroscopy 旋转坐标系NOE 谱ROTO ROESY-TOCSY Relay ROESY-TOCSY 接力谱SC Scalar Coupling 标量偶合SDDS Spin Decoupling Difference Spectroscopy 自旋去偶差谱SE Spin Echo 自旋回波SECSY Spin-Echo Correlated Spectroscopy 自旋回波相关谱SEDOR Spin Echo Double Resonance 自旋回波双共振SEFT Spin-Echo Fourier Tran sform Spectroscopy （with J modulati on）（J-调制）自旋回波傅立叶变换谱SELINCOR SELINQUATE SFORD SNR or S/NSelective Inverse Correlation 选择性反相关Selective INADEQUA TE 选择性双量子（实验）Single Frequency Off-Resonance Decoupling 单频偏共振去偶Signal-to-noise Ratio 信/ 燥比SQF Single-Quantum Filter 单量子滤波SRTCF TOCSY TORO TQF WALTZ-16 Saturation-Recovery 饱和恢复Time Correlation Function 时间相关涵数Total Correlation Spectroscopy 全(总)相关谱TOCSY-ROESY Relay TOCSY-ROESY 接力Triple-Quantum Filter 三量子滤波A broadband decoupling sequence 宽带去偶序列WATERGATE Water suppression pulse sequence 水峰压制脉冲序列WEFTZQ(C) ZQF T1T2 tmWater Eliminated Fourier Transform 水峰消除傅立叶变换Zero-Quantum (Coherence) 零量子相干Zero-Quantum Filter 零量子滤波Longitudinal (spin-lattice) relaxation time for MZ 纵向(自旋- 晶格)弛豫时间Transverse (spin-spin) relaxation time for Mxy 横向(自旋-自旋)弛豫时间T C rotational correlation time 旋转相关时间。

N缓冲层上低温生长AIN单晶薄膜

收稿日期:2002-10-16. 基金项目:国家自然科学基金资助项目(69976008)1材料、结构及工艺G a N 缓冲层上低温生长Al N 单晶薄膜秦福文1,顾　彪1,徐　茵1,杨大智2(1.大连理工大学电气工程与应用电子技术系,辽宁大连116024;2.大连理工大学材料科学与工程系,辽宁大连116024)摘　要:　采用电子回旋共振等离子体增强金属有机物化学气相沉积(ECR 2PEMOCVD )技术,在α2Al 2O 3(0001)(蓝宝石)衬底上,分别以高纯氮气(N 2)和三甲基铝(TMAl )为氮源和铝源低温生长氮化铝(AlN )薄膜。

利用反射高能电子衍射(RHEED )、原子力显微镜(AFM )和X 射线衍射(XRD )等测量样品,研究了AlN 缓冲层和氮化镓(G aN )对六方AlN 外延层质量的影响,实验表明在G aN 缓冲层上能够低温生长出C 轴取向的AlN 单晶薄膜。

关键词:　AlN ;G aN ;氢等离子体清洗;氮化中图分类号:TN304.053　文献标识码:A 文章编号:1001-5868(2003)01-0032-05Study on Al N Film G row n on G a N Buffer Layer at Low T emperatureQ IN Fu 2wen 1,GU Biao 1,XU Y in 1,YAN G Da 2zhi 2(1.Department of E lectrical E ngineering and Applied E lectronics ,Dalian U niversity of T echnology ,Dalian 116024,CHN;2.Department of Material Science and E ngineering ,Dalian U niversity of T echnology ,Dalian 116024,CHN )Abstract :　AlN film has been grown on α2Al 2O 3(0001)substrate by ECR 2PAMOCVD technique at low temperature using TMAl and highly pure N 2as Al and N sources ,respectively.The effects of G aN buffer layer and AlN buffer layer on the quality of AlN epilayer have been investigated through the measurement of RHEED ,TEM and XRD.The result shows that C axis oriented AlN single crystal film can be grown on G aN buffer layer at low temperature.K ey w ords :　AlN ;G aN ;hydrogen plasma cleaning ;nitridation1　引言宽带隙的Ⅲ族氮化物半导体材料AlN 和G aN ,其带隙能量分别为6.2eV 和3.39eV ,是目前制备蓝光到紫外光波段的发光二极管(L ED )、激光二极管(LD )等光电器件的首选材料。

铝合金凝固中超声诱导纳米tib2颗粒在α-al晶内分布及其强韧化机理

铝合金凝固中超声诱导纳米tib2颗粒在α-al晶内分布及其强韧化机理下载温馨提示：该文档是我店铺精心编制而成，希望大家下载以后，能够帮助大家解决实际的问题。

文档下载后可定制随意修改，请根据实际需要进行相应的调整和使用，谢谢!并且，本店铺为大家提供各种各样类型的实用资料，如教育随笔、日记赏析、句子摘抄、古诗大全、经典美文、话题作文、工作总结、词语解析、文案摘录、其他资料等等，如想了解不同资料格式和写法，敬请关注!Download tips: This document is carefully compiled by the editor. I hope that after you download them, they can help you solve practical problems. The document can be customized and modified after downloading, please adjust and use it according to actual needs, thank you!In addition, our shop provides you with various types of practical materials, such as educational essays, diary appreciation, sentence excerpts, ancient poems, classic articles, topic composition, work summary, word parsing, copy excerpts, other materials and so on, want to know different data formats and writing methods, please pay attention!铝合金凝固中超声诱导纳米TiB2颗粒在α-Al晶内分布及其强韧化机理导言铝合金在工业制造中广泛应用，然而其机械性能与特性之间的平衡一直是研究者们关注的焦点。

材料的热电性能

材料的热电性能热电材料是利用固体内部载流子运动实现热能和电能直接转换的功能材料。

它的产生于材料的热电性能密不可分,材料的热电性能可以总结为塞贝克效应,帕尔贴效应，汤姆孙效应。

塞贝克效应热电现象最早在1823年由德国人Seebeck发现。

当两种不同导体构成闭合回路时,如果两个节点处电温度不同，则在两个节点之间将会产生电动势,且在回路中有电流通过，该现象被叫做Seebeck效应，此回路称为热电回路，回路中出现的电流称为热电流，回路中出现的电动势称为塞贝克电动势.塞贝克系图 1 塞贝克效应示意图数可表示为:式中，V表示电动势；T表示温度,S的大小和符号取决于两种材料和两个结点的温度.当载流子是电子时，冷端为负，S是负值；如果空穴是主要载流子类型，那么热端是负，S是正值。

帕尔贴效应1834年，法国钟表匠Pletier发现了Seebeck效应的逆效应，即电流通过两个不同导体形成的接点时接点处会发生放热或吸热现象,称为帕尔贴效应。

帕尔贴系数可表示为:P表示单位时间接头处所吸收的帕尔贴热；I表示外加电源所提供的电流强度。

汤姆孙效应当电流通过具有一定温度梯度的导体时，会有一横向热流流入或流出导体，其方向视电流方向和温度梯度的方向而定。

在实际应用中，以无量纲的ZT值来衡量材料的热电性能：式中，σ为电导率；k为热导率；S是塞贝克系数；T为温度。

σS2又被称作功率因子，用于表征热电材料的电学性能。

从上式可以得出，提高热电材料的能量转换效率可以通过增大其功率因子或降低其热导率来实现,但这3个参数并非独立的，它们取决于材料的电子结构和载流子的散射情况。

为了提高塞贝克系数，材料中应该只有单一类型的载流子，n型和p型载流子同时存在会导致两种载流子都向冷端移动，从而降低塞贝克电压。

低的载流子浓度会增大塞贝克系数，塞贝克系数公式如下：n为载流子浓度,m为载流子有效质量.大的载流子有效质量会提高塞贝克系数，但是会降低电导率。

m和态密度有关,载流子的有效质量会随着费米能及附近的态密度增加而增加。

聚合物锂离子电池用凝胶电解质的研究进展_倪冰选

第28卷第3期2009年6月天津工业大学学报JOURNAL OF TIANJIN POLYTECHNIC UNIVERSITYVol.28No.3June 2009聚合物锂离子电池用凝胶电解质的研究进展倪冰选1，2，焦晓宁1，2，阮艳莉2，3（1.天津工业大学纺织学院，天津300160；2.天津工业大学改性与功能纤维天津市重点实验室，天津300160；3.天津工业大学材料科学与化学工程学院，天津300160）摘要：综述聚氧化乙烯（PEO ）、聚偏氟乙烯（PVDF ）、聚甲基丙烯酸甲酯（PMMA ）和聚丙烯腈（PAN ）等聚合物材料用作锂离子电池凝胶电解质的特性.PAN 体系凝胶电解质的离子电导率一般在10-3S/cm 数量级，其锂离子迁移数比PEO 体系大，可达到0.5；与PAN 基凝胶电解质相比，以PMMA 为基的凝胶电解质与锂电极的界面稳定性和循环性能更好，但是机械强度较差；PVDF 大分子链上含有很强的推电子基（-CF 2），且介电常数较高（ε=8.4），有利于促进锂盐更充分的溶解，增加载流子浓度.提出添加无机纳米粒子的凝胶电解质是目前的研究热点，是凝胶电解质的发展趋势.关键词：聚合物锂离子电池；凝胶电解质；静电纺中图分类号：TM912.9文献标识码：A文章编号：1671－024X （2009）03－0048－05Research progress of gel electrolyte for polymer lithium-ion batteryNI Bing-xuan 1，2，JIAO Xiao-ning 1，2，RUAN Yan-li 2，3（1.School of Textile ，Tianjin Polytechnic University ，Tianjin 300160，China ；2.Tianjin Municipal Key Laboratory of Fiber Modification and Functional Fiber ，Tianjin Polytechnic University ，Tianjin 300160，China ；3.School of Material Science and Chemical Engineering ，Tianjin Polytechnic University ，Tianjin 300160，China）Abstract ：The polymer materials ′characteristics of polyethylene oxide （PEO ），polyvinylidene fluoride （PVDF ），polymethyl methacrylate （PMMA ）and polyacrylonitrile （PAN ）for lithium -ion battery gel electrolyte are summarized.Ionic conductivity of PAN system gel electrolyte is 10-3S/cm magnitude commonly ，and its lithium-ion ′s transferred amount is larger than PEO system and can reach 0.5.PMMA-based gel electrolyte and lithium electrode ′s interface stability ，cycle performance are better than PAN-based gel electrolyte ，but mechanical strength is poor than PAN-based.PVDF macromolecular chain contains strong electron group （-CF 2），and its high dielectric constant （ε=8.4）is beneficial to promote Lithium Salt Dissolved more sufficiently ，increase carrier concentration.Gel electrolyte with inorganic nano particle is the research hotspot at present ，and it ′s the progress direction of gel electrolyte.Key words ：polymer lithium-ion battery （PLIB ）；gel electrolyte ；electrospinning收稿日期：2009-03-12作者简介：倪冰选（1983—），男，硕士生；焦晓宁（1958—），女，教授，硕士生导师.E-mail ：nibingxuan12@1973年，Wright 等首次发现了聚氧化乙烯（PEO ）与碱金属盐络合具有离子导电子的现象，使固体电解质的研究进入一个新的阶段，但固体电解质的室温电导率与实际应用要求相距较远.为了克服这一问题，Feuillade 等在1975年首先提出了凝胶电解质，后来由Abraham 等作了深入研究.聚合物凝胶通常被定义为一个被溶剂溶胀的聚合物网络体系，其独特的网络结构使凝胶同时具有固体的粘聚性和液体的分散传导性.1995年美国Bellcore 公司公开了一种新型凝胶聚合物电解质用于发展聚合物锂离子电池的技术[1-2].自此，对聚合物锂离子电池用凝胶电解质的研究方兴未艾.聚合物锂离子电池是在液态锂离子电池的基础上开发出的最新一代锂离子电池，其构成是采用具有离子导电性并兼具隔膜作用的聚合物电解质代替液态锂离子电池中的电解液，凝胶电解质是由聚合物、增塑剂和锂盐通过一定的方法形成的具有合适微孔第3期结构的凝胶聚合物网络，利用固定在微结构中的液态电解质分子实现离子传导，它的室温电导率一般在10-3S/cm数量级[3].从1975年凝胶聚合物电解质（GPE）首次报道以来，有多种体系的凝胶聚合物电解质得到了开发与研究.研究较多、性能较好的有以下几种类型聚合物：聚氧化乙烯（PEO）系、聚丙烯腈（PAN）系、聚甲基丙烯酸甲酯（PMMA）系和聚偏氟乙烯（PVDF）系等.本文从不同聚合物原料角度介绍凝胶电解质的研究进展.1聚丙烯腈（PAN）系聚丙烯腈（PAN）系电解质的研究源于1975年，是研究最早的凝胶电解质.PAN是一种耐热性能和阻燃性能良好的聚合物，并且表现出很宽的电化学稳定范围，因此得到了广泛的关注[4-5].Feuiliade和Perche等人[6]对PAN体系凝胶聚合物电解质（GPE）进行了系统的研究，他们选取不同的溶剂，不同的锂盐，按不同的配比制备了凝胶聚合物电解质，发现PAN体系GPE的离子电导率一般在10-3 S/cm数量级，其锂离子迁移数也比PEO体系大，可达到0.5.同时，Perche在研究中还发现，由于PAN链上含有强极性基团-CN，与锂电极相容性差，GPE膜与锂电极界面钝化现象严重，随着时间延长，其电池内阻会不断增大，这限制了PAN体系凝胶电解质在聚合物锂离子电池中的应用.为了提高PAN基凝胶聚合物电解质的性能，人们尝试多种方法对其进行了改性，主要有共聚，共混和添加无机填料等.Choi等[7]把PAN和PEO共混（10PEO-40PAN-12LiClO4-38EC/BL）后所制备的电解质膜，离子电导率可达到10-3S/cm数量级，而且PEO的加入可以提高PAN凝胶电解质的机械强度.共混体系中一般包含两相：一相是富增塑剂相，提供离子的导电通道；一相含增塑剂少，主要起力学支撑作用.两相的相对比例及微观形态对聚合物电解质膜的离子电导率和力学性能影响很大.聚合物-溶剂之间的亲和力是影响凝胶电解质膜的溶剂保液能力、机械性能和室温电导率的关键因素.高亲和力的聚合物具有较高的溶剂保液能力和室温电导率，但其机械强度较差；而低亲和力的聚合物具有高的机械强度，而电导率则较低.将亲和力低的聚合物和亲和力高的聚合物共混可以制得性能优良的凝胶聚合物电解质膜.Lee等[8]合成的P（AN-MMA）表明，共聚后聚合物离子电导率大大增加：-15℃下电导率为1.7×10-4S/cm，25℃下电导率高达1.3×10-3S/cm.通过DSC测试表明：聚合物有2个玻璃化转变温度，较高的代表富聚合物相，较低的代表富增塑剂相.中国科学院物理研究所和凝聚态物理中心的李子荣，王刚等[9]利用脉冲梯度场NMR方法直接测量了不同温度下的不同组分PAN为基的凝胶聚合物电解质PAN-EC/PC-LiClO4中锂离子的自扩散系数D.结果表明，锂离子的自扩散系数D依赖于锂盐质量分数x%，并且在x从5到20范围内，当x=10时D有最大值，这与锂离子跳跃的传输机制及同时受到增塑剂EC与聚合物PAN网络的相互作用有关.2聚氧化乙烯（PEO）系20世纪80年代以来，高分子量的PEO商品得到了广泛开发.聚氧化乙烯是由环氧乙烷经多相开环生成的高分子量均聚物，具有-CH2CH2O-重复单元，其玻璃化转变温度约62℃，是一种白色的水溶性树脂[4]. PEO是结晶度较高（70%~80%）的线型化合物，具有螺旋构型[10].PEO的导电主要由非晶相的链段运动所引起，短链段的运动导致阳离子和聚合物配位键松弛断裂，阳离子在局部电场作用下进行扩散跃迁.一般认为，PEO基聚合物电解质的离子传导主要是通过锂离子与醚氧原子之间不断发生络合、解络合过程而进行的，离子电导率主要取决于聚合物电解质中自由载流子数目和聚合物链段的运动性.在聚合物电解质中，离子-离子、离子-聚合物基体间的相互作用及其对离子迁移的影响一直是重要的研究课题.程琥等[11]通过傅立叶变换红外光谱（FTIR）对P（EO）n LiX [X=N（SO2CF3）2，SCN，ClO4]（n=4~60）聚合物电解质的离子缔合行为进行了研究，结果表明，在PEO-LiSCN 体系中缔合现象较为严重，在高浓度时，LiSCN主要以离子对、离子簇以及二聚体形式存在，自由离子含量较少，而对于LiTFSI和LiClO4体系，则以自由离子形式为主，随着锂盐的加入，由于其阴离子的增塑作用使聚氧化乙烯（PEO）中的晶相成分逐渐向无定形相转化.当锂盐含量增加到一定程度，体系中会有不同晶相复合物形成.为了得到电导率高的电解质，以PEO为基体的聚合物电解质的研究目标是要得到玻璃化转变温度T g 低、无定形相稳定且含量多的凝胶电解质，主要可以通过以下几方面来实现：形成共聚物、生成交联聚合物、加入掺杂盐、增塑剂和无机填料等。

电化学表面增强拉曼光谱的量子化学研究

电化学表面增强拉曼光谱的量子化学研究庞然;金曦;赵刘斌;丁松园;吴德印;田中群【摘要】Considering the study of electrochemical surface adsorption and reaction processes at the molecular level, Surface-enhanced Raman spectroscopy( SERS) shows its particular merits and provides a powerful tech-nical method for this study. However, the mechanism of enhancement needs to be further explored. This re-view summarizes the systematic work on electrochemical SERS ( EC-SERS ) by combining quantum chemistry calculations. On the basis of these studies, we can make deep insight for extracting the physical and chemical information in EC-SERS spectra. Focusing on adsorption of pyridine on the electrochemical surface, adsorption and reactional process of water on the surface, and surface coupling reaction for p-aminothiophenol, we had illustrated the nature of the adsorption and photochemical reactions on the electrochemical surface.%对于在分子水平上研究电化学表面吸附和反应过程，表面增强拉曼光谱( SERS)显示出了其独到的优势，提供了有力的技术方法，但对于其表面增强机理仍有待深入研究。

硬软酸碱理论(HSAB理论)

硬软酸碱理论（HSAB理论)对于质子酸碱，我们可用pK来描述酸碱的强度,用pH或HO来表示溶液的酸度.但是对于不涉及质子转移的路易斯酸碱,我们只能通过比较它们形成的配合物的热力学稳定性来估计它们的强度。

根据路易斯酸碱电子论的定义,认为在反应中能给出电子对的物质是碱，能接受电子对的物质是酸。

在配合物中，中心离子是电子对的接受体,是路易斯酸;配位体是电子对给予体，是路易斯碱.1963年皮尔逊（Peauson）提出了软硬酸碱（Soft and Hard acids and bases，简称SHAB）概念，即根据酸、碱对外层电子控制的程度,应用了“软"和“硬”两字进行分类，把接受孤对电子能力强、对外层电子吸引得紧、没有易极化的电子轨道、电荷半径比较大的金属离子叫“硬酸”；把接受电子能力弱、对外层电子抓得松、易极化、电荷半径比较小的叫“软酸”，介乎二者之间的金属离子叫“交界酸”.按同样道理也把配体分为软、硬和交界三类。

给出电子对的原子电负性大、对外层电子吸引力强、不易失去电子、变形性小的叫做“硬碱”；给出电子对的原子电负性小、对外层电子吸引力弱、易给出电子、变形性大的叫做“软碱"；介乎二者之间的为“交界碱”。

硬酸和硬碱之所以称为“硬”是形象化地表明它们的不易变形；软酸和软碱之所以称为“软”是表明它们较易变形。

由于路易斯酸碱多种多样，分类比较粗糙，反应也较复杂，还没有大家公认的定量理论，目前只有一个软硬酸碱规则，其内容是：硬酸倾向于与硬碱相结合,而软酸倾向于与软碱结合.用通俗的话来说，是“硬亲硬,软亲软，软硬交界就不管”.所谓软硬交界就不管的意思是指中间酸（交界酸）与软、硬碱也能结合，中间碱与软、硬酸也能结合，但稳定性较前者差。

显然这一规则既不定量，而且有不少例外，但它仍是一个很有用的简单规则，能用它说明大量的事实，并能作一定的预测。

例如能对化合物相对稳定性给予较好的解释，如HF和HCl很稳定，但HI不稳定.从表7-11可知H是硬酸，F、Cl是硬碱，而I是软碱，前者硬－硬结合稳定，而后者硬－软结合不稳定。

高效电池与钙钛矿电池的测试技术进展

高效电池需要长脉冲的太阳模拟器
SJTU 上海交大 Solar Energy Institute太阳能研究所
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1、高效电池的特性

一般具有较宽的光谱响应波段，蓝光响应明显电容效应明显（势垒电容和扩散电容）光照会引起pn结的内部电场的变化，扫描电压造成势垒电容的变化，进而影响电池IV特性
SJTU 上海交大 Solar Energy Institute太阳能研究所
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1、PERC电池的光谱响应
SJTU 上海交大 Solar Energy Institute太阳能研究所
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1、等效电路与IV方程
SJTU 上海交大 Solar Energy Institute太阳能研究所
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2、高效太阳电池的测试对策
SJTU 上海交大 Solar Energy Institute太阳能研究所
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8、钙测试结束后, 选取最大功率输出点(Maximumpower output, MPP)处的偏压 VMPP, 进行恒压条件下的电流测量, 直至器件稳定, 并以最终获得结果计算光电转换效率。 2、采用稳态太阳模拟器需要温控装置和良好导热的钙钛矿电池。 3、电压扫描一定要足够慢。

SJTU 上海交大 Solar Energy Institute太阳能研究所
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8、钙钛矿电池迟滞效应的原因分析
猜想：磁滞回线铁电效应与正反扫IV曲线理论计算表明在短路差异是否有联系？和开路条件下钙钛矿中形成了一定的偶极取向，利用压电力显微镜(PFM)从实验上直接观测到了铁电畴的存在
SJTU 上海交大 Solar Energy Institute太阳能研究所
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a r X i v :c o n d -m a t /0306688v 1 [c o n d -m a t .s u p r -c o n ] 27 J u n 2003Strong electron-Boson coupling eﬀect in the infrared spectra of Tl 2Ba 2CaCu 2O 8+δN.L.Wang,∗P.Zheng,J.L.Luo,and Z.J.ChenKey Laboratory of Extreme Conditions Physics,Institute of Physics,Chinese Academy of Sciences,P.O.Box 603,Beijing 100080,P.R.ChinaS.L.Yan,L.Fang,and Y.C.MaDepartment of Electronics,NanKai University,Tianjin 300071,P.R.ChinaWe report on a study of the in-plane infrared response of a Tl 2Ba 2CaCu 2O 8+δﬁlm with T c =108K.The ﬁngerprint evidence for a strong electron-Boson coupling has been observed.The raw reﬂectance below T c exhibits a knee structure at around 650cm −1and the ratio of the reﬂectances below and above T c displays a pronounced minimum at around 1000cm −1.In particular,the features appear at higher energy scale than other bilayer cuprates with T c around 90-95K.The gap amplitude and the Boson mode energy were extracted from the analysis of the bosonic spectral function.In comparison with several other optimally doped high-Tc cuprates,we ﬁnd that the gap size scales with T c ,but Boson mode energy has a tendency to decrease.PACS numbers:74.25.Gz,74.72.Jt,74.78.BzSuperconductivity requires the electrons being glued together in pairs.In conventional superconductors the pairing is due to the coupling between electrons and phonons.Although the Boson responsible for mediating the pairing or the ”glue”in high temperature supercon-ducting cuprates (HTSC)remains elusive,evidence for strong electron-Boson coupling eﬀects began to accumu-late in various charge spectroscopies.In particular,many of them are suggestive of a magnetic mode to glue the charge carriers together.For example,the photoemis-sion line shape near (π,0)in many of the HTSC in the superconducting state is characterized by a sharp peak,followed at higher energy by a dip and broad hump.1As one moves towards the zone diagonal,a kink in the dispersion develops.2,3The kink appears at the same en-ergy scale as the dip.2These anomalies were widely be-lieved to result from the interaction of electrons with a collective mode which appears below T c .The inferred mode energy and its temperature dependence agree well with the magnetic resonance observed at (π,π)by neu-tron scattering.4,5,6The coupling of the electrons with magnetic mode has also been indicated in the tunneling spectra of Bi 2Sr 2CaCu 2O 8+δ(Bi2212),where a sharp dip was observed at a voltage beyond the gap edge 2∆.7Study of electron-phonon coupling eﬀects in infrared spectra of conventional superconductors began in early 1970’s.8Progresses have been made in recent years.Mar-siglio et al.9showed that the electron-phonon spectral function α2F (Ω)is closely related to the optical scatter-ing rate14πRe14πσ1(ω)2πd 2τ(ω)](2)is very close to α2F (Ω)in the phonon region withadditional wiggles beyond the phonon cutoﬀ.How-ever,no correlation between the structure in W (ω)and phonon density of states has been established for high-T c cuprates.Instead,signature of the spin resonance mode in neutron experiment is also indicated in the in-plane infrared spectrum.Carbotte et al.10analyzed op-tical conductivity σ(ω)in magnetically mediated d-wave superconductors and argued that W (ω)of equ.(2)still gives a good approximation to the charge-spin spectral density and that the spin resonance feature should show up in W(ω)as a result of coupling of the electrons to this magnetic mode.In particular,the peak in W(ω)below T c is correlated to ∆+Ω,where Ωis the energy of the spin resonance mode.11In another theoretical study of optical conductivity in superconductors with quasiparti-cles strongly coupled to their own collective spin modes,Abanov et al.12emphasized that a deep minimum lo-cating at 2∆+Ωs in W (ω)is more relevant to super-conductivity.They also identiﬁed two weaker high fre-quency singularities at 4∆and 2∆+2Ω.More recently,Shulga 13pointed out that the minimum in the ratio of the raw reﬂectance R s (ω)/R n (ω)is the key evidence for the Boson-mediated superconductivity.He showed that the minimum locates at frequency of 2∆+Ω,where the scattering rate displays a peak.Obviously,identifying these features in the infrared spectra represents the ﬁn-gerprint evidence for the electron-Boson coupling in high-T c cuprates.In this paper,we report on a study of the in-plane infrared response of a Tl 2Ba 2CaCu 2O 8+δ(Tl2212)ﬁlm with T c =108K.The above mentioned features in re-ﬂectance spectra are clearly observed,providing unam-biguous evidence for the strong electron-Boson coupling eﬀect in this bilayer cuprate with higher T c .In particu-lar,the features appear at higher energy scale than other bilayer cuprates with T c around 90-95K.We compared the results on Tl2212with other high-T c cuprates,and suggest that a magnetic resonance mode exists in this bilayer material.2010********60(0018)(0014)(0012)(0010)(008)(006)(004)(002)L a A l O 3 (002)L a A l O 3 (001)I n t e n s i t y (a .u .)2θ (degree)FIG.1:The X-ray diﬀraction pattern for a Tl2212ﬁlm.All the sharp peaks can be assigned to the (00l)peaks of Tl2212except those of LaAlO 3substrate.Epitaxial Tl 2Ba 2CaCu 2O 8+δﬁlms were grown on LaAlO 3substrates by dc magnetron sputtering and a post-annealing process.X-ray diﬀraction measurements conﬁrm that the ﬁlms were strongly textured with the c-axis parallel to the c-axis of the substrate,as shown in Fig. 1.Details of the ﬁlm growth were described elsewhere.14Optimally doped ﬁlms with thickness of 4000˚A were used for optical reﬂectance measurements.The reﬂectance measurements from 50to 25000cm −1for E ab-plane were carried out on a Bruker 66v/S spec-trometer with the samples mounted on optically black cones in a cold-ﬁnger ﬂow cryostat using an in situ over-coating technique.15The optical conductivity spectra were derived from the Kramers-Kronig transformation.Figure 2shows the temperature dependent resistivity of the Tl2212ﬁlm.The zero-resistance temperature T c 0is 108K,which is much higher than other optimally doped bilayer cuprates with T c 0∼90-95K.The raw reﬂectances R (ω)from 50to 2000cm −1and the calcu-lated optical conductivities σ1(ω)at diﬀerent tempera-tures are displayed in Fig.3(a)and 3(b),respectively.It should be pointed out that the thickness of 4000˚A of our ﬁlms appears suﬃcient to avoid signals from the substrate.For this purpose,we show,in the inset of Fig.3(b),the far-infrared reﬂectance spectrum measured on LaAlO 3substrate at room temperature.The spectrum is dominated by phonon peaks.However,no clear features at the energies corresponding to the phonon peaks could be detected in R (ω)of the Tl2212ﬁlm.In the normal state,the reﬂectance spectra show roughly linear frequency dependence.With decreasing temperature,the low-ωR (ω)increases,being consistent with the metallic behavior of the sample.At 10K in the superconducting state,R (ω)shows a knee struc-ture at around 650cm −1.Above this frequency,the re-ﬂectance drops fast and becomes lower than the normal-state values at around 1000cm −1.R (ω)recovers the linear-frequency dependence at higher frequencies.Simi-lar but weak behaviors were seen at 95K,which is close to T c .The change of the R (ω)in the superconduct-ing state with respect to the normal state could be seenρ (µΩ c m )T (K)FIG.2:The resistivity vs.temperature curve for the ﬁlm with zero resistivity at 108K05001000150020002000400060002004006000.00.51.0(b)σ1 (Ω-1c m -1)Wave number (cm -1)0.80.91.0(a)R10 K 95 K 120 K 200 K 300 KRWave number (cm -1)FIG.3:ab-plane optical data from 50to 2000cm −1of the op-timally doped Tl-2212with T c =108K.(a)the temperature-dependent reﬂectance and (b)the temperature-dependent σ1(ω).Inset:the far-infrared reﬂectance of the substrate LaAlO 3at room temperature.more clearly from the plot of the ratio of the reﬂectance below T c over that above T c .Fig.4(a)shows the ratio of R 10K (ω)/R 120K (ω)as a function of frequency.It be-comes evident that a maximum at around 650cm −1and a minimum at around 1000cm −1exist in the plot.The scattering rate 1/τ(ω)spectra at 10K and 120K,ex-tracted from equ.(1)with the use of plasma frequency of 1.6×103cm −1determined by summarizing the optical conductivity up to 1eV,are displayed in Fig.4(b).We can see that,at frequencies corresponding to the maxi-mum and minimum in the R 10K (ω)/R 120K (ω)plot,the 1/τ(ω)at 10K exhibits a rapid rise and a peak or a sub-stantial overshoot of the normal state result,respectively.3050010001500200010002000(b)1/τ (c m -1)Wave number (cm -1)120 K 10 K0.951.001.051.10(a)R 10K /R 120KR s /R nFIG.4:(a)The reﬂectance ratio below and above T c as a function of frequency.(b)The frequency-dependent scatter-ing rate 1/τ(ω)spectra at 10K and 120K.Obviously,the features caused by strong electron-Boson coupling as discussed by Shulga 13were ob-served in infrared spectra of the optimally doped Tl 2Ba 2CaCu 2O 8+δwith T c 0=108K.The present work is very suggestive that a simple deviation or suppres-sion from the linear-frequency dependence in 1/τ(ω),i.e.the so-called ”pseudogap”feature in ab-plane op-tical response,may not be a direct indication for the Boson mode being coupled to the electronic spectra.The dip in the reﬂectance ratio R s /R n or the ”over-shoot”in 1/τ(ω)is more essential.We note that the overshoot feature was observed previously on opti-mally doped YBa 2Cu 3O 7−δ(YBCO)by Basov et al.16and HgBa 2Ca 2Cu 3O 8+δ(Hg1223)by McGuire et al.17.The features in Bi2212are weak,but a recent study by Tu et al.18made it clear that those features ex-ist.However,the ”overshoot”behavior is absent in La 2−x Sr x CuO 4+δ(LSCO),although the suppression of low-ωscattering rate is still observed.19Another remarkable observation here is that the ”over-shoot”feature in 1/τ(ω)appears at higher energy than the corresponding features in YBCO and Bi2212,which are in the range of about 800-900cm −1.16,18We note that the feature in Hg1223with T c =130K locates at even higher frequency beyond 1100cm −1.17Therefore,there is a tendency that the energy of the feature scales with the superconducting transition temperature.There are two diﬀerent opinions about the origins of the Bosons seen in charge spectroscopies.One is phonon origin 3and the other the magnetic mode origin.We found that the phonon scenario is inconsistent with the present experiment,for the feature is seen only in the superconducting state,whereas phonons exist also in the0500100015002000-3-2-10123(b)W (ω)Wave number (cm -1)T=10 K0.02.0x1064.0x1066.0x106(a)ω/τ (c m -1)210 KPoly_fit (20 terms)FIG.5:(a)The experimental data of ω/τ(ω)at 10K to-gether with a 20-term polynomial ﬁt.(b)The bosonic spec-tral function W(ω)vs.frequency derived from the polynomial ﬁt curve.normal state.Recent study on the oxygen isotope ef-fect in the ab-plane optical properties of YBCO also ruled out the phonons as the main player.20By contrast,Tl2212shares the same coupling behavior as the YBCO and Bi2212,where suggestions for the magnetic origin were proposed from the inversion of the ab-plane optical conductivity.10,18,21Note that,neutron experiments re-vealed a main diﬀerence for the resonances in optimally doped YBCO and Bi2212:the resonance peak in the later material exhibits a considerable broadening in both en-ergy and wave vector,which was interpreted to be caused by the intrinsic inhomogeneities in Bi2212.22Therefore,We can ascribe the weak ”dip”or ”overshoot”features in Bi2212to the broadening of the resonance peak.The ab-sence of those features in LSCO might be related to the absence of the magnetic resonance.Since the ”overshoot”feature in Tl2212is prominent,like the case in YBCO,we suggest that a sharp magnetic resonance mode exists in this material.The above discussion on the dip or ”overshoot”be-havior appears at frequency of 2∆+Ω,which contains the superconducing gap and a Boson mode.It would be much desired to separate the two diﬀerent energy scales.This might be achieved from the analysis of the bosonic spectral function W(ω)deﬁned in equ.(2).Since W(ω)is obtained by taking the second derivative of the func-tion ω/τ(ω),a smoothing of the experimental data is re-quired.Tu et al.18suggested an unambiguous method to extract W(ω)by ﬁtting the experimental measured quan-tity ω/τ(ω)with high-order polynomial.This method has been used in present analysis.In Fig.5(a),the ω/τ(ω)at 10K is shown together with a 20-term poly-nomial ﬁt.The resulting spectral function W(ω)vs.fre-4E n e r g y S c a l e (m e V )T c (K)FIG.6:Plots of ∆,Ωand the energy of overshoot (2∆+Ω)versus T c for several optimally doped cuprates.The data for Bi221218and YBCO 10are from inversion of optical spectra.The ∆values for Bi2201and Bi2223are from photoemission study (peak position gap).23Hg1223data is from 17.The Ωvalue for Tl2201is from neutron experiment.24The straight lines are for eye guidance.We start to put straight lines for (2∆+Ω)and Ω,the third one for ∆is then extracted.quency is displayed in Fig.5(b).We can see a large max-imum at about 650cm −1,a deep negative minimum at 1000cm −1,and a weak maximum at around 1300cm −1.According to Carbotte et al.,10the large maximum cor-responds to ∆+Ω.In terms of Abanov et al.12,the other two features correspond to 2∆+Ωand 2∆+2Ω,respec-tively.Then,we obtain ∆=350cm −1(or 43meV)and Ω=300cm −1(or 37emV)for Tl 2Ba 2CaCu 2O 8+δ.We ﬁnd obviously that the extracted gap ∆is larger than the values for Bi2212(35meV)and YBCO (28meV),but the Boson mode energy Ωis smaller than the corresponding values of 43meV for Bi2212and 41meV for YBCO.10,18Since the T c of Tl2212is very close to that of Bi2223,it would be interesting to compare the result with Bi2223.The gap amplitudes for n=1,2,3compounds in Bi-based family have been studied in pho-toemission experiments by Feng et al.23They found that the leading-edge-midpoint (peak position)gap values are 10(21),24(40),30(45)meV for n=1,2,3systems,respectively.It is seen that the gap values for Bi2212and Tl2212extracted from in-plane optical data are more closer (but a bit smaller)to their peak position gap val-ues for n=2and 3systems.In Fig.6,we plot ∆,Ωand the energy of ”overshoot”(2∆+Ω)versus T c for several optimally doped cuprates where those data are available.We ﬁnd that the gap increases with T c ,but the Boson mode energy has the tendency to decrease with T c .In the ﬁgure,the data of YBCO appear to deviate substan-tially from the scaling behavior.The reason is not clear.One possibility is that the existence of the Cu-O chains,which also become superconducting below T c ,helps to enhance T c ,even though its gap value is smaller than Bi2212and Tl2201.Earlier studies have established that the T c in opti-mally doped cuprates is proportional to the condensed carrier density n s .The present study shows that T c is also correlated with the energy scale of the superconduct-ing gap ∆.Within current understanding,both the n s and ∆are important quantities characterizing supercon-ducting state.∆reﬂects the pairing strength,while n s is an indication of the phase stiﬀness of the pairing.23,25To achieve maximum T c ,both the superconducting gap and the condensate should be maximized.Finally,we brieﬂy comment on the two sizeable fea-tures at 600cm −1and 230cm −1,which are present in all measured temperatures.Since the frequencies are away from the phonon modes of the substrate,26they are not likely to come from the substrate due to the possible leak-age of the ﬁlm in the long wave length region.The high-frequency mode was seen in other high-Tc cuprates,e.g.Bi221218and YBCO 16,20,and was assigned to the trans-verse optic phonon (Cu-O stretching mode).The 230cm −1mode was also reported in earlier reﬂectance study on YBCO,where it was suggested to be of electronic origin for the spectral weight of the mode was found to be an order of magnitude larger than what is expected for a paring the present data with those studies,we found that the high-frequency mode appears as an antiresonance rather than a peak in the conduc-tivity spectra,and the strength of the 230cm −1mode is not weakened very much at high temperature,which is in contrast to the reported behavior in YBCO.Further studies are required to illustrate the diﬀerence.In summary,we have presented a set of high-quality in-plane optical data for Tl 2Ba 2CaCu 2O 8+δ(Tl2212)with T c =108K.The ﬁngerprint evidence for strong electron-Boson coupling eﬀect has been observed in reﬂectance spectra for this bilayer cuprate with higher T c .In par-ticular,the energy scale of the feature appears at higher energy than other bilayer cuprates with T c around 90-95K.The gap amplitude and the Boson mode energy were extracted from the analysis of the bosonic spectral function.It is found that the gap size scales with T c for diﬀerent cuprates.We discussed the origin of the Boson and compared the results on Tl2212with other high-T c cuprates.This work is supported by National 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