Effects of Electron-Phonon Interaction on Linear and Nonlinear Optical Absorption in Cylindrical
无机功能材料电子—声子及声子—声子耦合的计算机模拟研究
谨以此文献给关爱我的家人与朋友论文提要晶格动力学是现代固体物理的基础之一。
晶体中的原子在热激发下，不断地在平衡位置附近振动。
这些由原子集体振动所产生的声子可以与许多激发态发生耦合，其中最主要的耦合是：电子-声子和声子-声子耦合。
它们决定了材料中与电子和声子输运相关的许多物理性质，比如金属的电导率、超导电性和热导率等。
本论文选取高压下氢化物和铁基方钴矿热电材料作为研究电子-声子和声子-声子耦合的对象，采用基于密度泛函理论的第一性原理从头算方法，进行了系统性的输运性质研究，获得如下创新性成果：1. 高压下预测的两个富氢磷族化合物（AsH8和SbH4）的超导转变温度都超过了100K；发现了二元氢化物高压性质的一般化学趋势。
系统探索了磷族氢化物的高压相图，发现所有的磷氢化物高压下都倾向于分解，砷氢和锑氢化物中发现存在两个稳定的富氢化合物（AsH8和SbH4）。
AsH8和SbH4的超导转变温度（T c）都超过100K。
特别是SbH4具有最高的能量稳定性，其合成压力只有150GPa。
通过对已探索的二元氢化物的理论数据挖掘，我们发现了氢化物高压性质的一般化学趋势，其高压下的热力学稳定性、成键特征和电声耦合等性质与组成元素在常压下的电负性差存在紧密的联系。
该研究工作为寻找稳定的固态氢化物以及探索高温超导电性提供了有价值的理论指导。
2. 发现了二元未填方钴矿材料FeSb3具有超低的本征晶格热导率，改变了人们在方钴矿体系中对热输运规律的传统认识。
室温下，FeSb3的晶格热导率只有1.14W/mK，是同类材料CoSb3的十分之一。
填充原子并未导致FeSb3的晶格热导率的降低，这改变了人们在方钴矿体系中的传统认识（填充原子会显著地降低方钴矿材料的晶格热导率）。
FeSb3中的超低晶格热导率主要来自于整个声子谱的软化，尤其是与结构中Sb-Sb共价键关联的低频光学支声子的软化相关。
3. 发现高电负性元素填充的方钴矿SnFe4Sb12具有超低的本征晶格热导率，为优化方钴矿材料的热电性能提供了新的途径。
一、主持与承担的项目 1、已完成的科研项目
黄文登，男，汉族，1978年4月出生，中共党员，凝聚态物理专业硕士，副教授。
1998年至2002年就读陕西理工学院物理系物理学专业，获学士学位；2002年至2005 年就读河南师范大学物理与信息工程学院，获硕士学位。
主要承担了大学物理、固体物理、物理学专业外语和物理实验等教学工作。
目前在凝聚态物理学科开展科学研究工作，主要研究方向为半导体物理、低维物理。
已在SCI、EI 源期刊、核心期刊上发表学术论文15篇。
被SCI收录7篇，EI收录2篇。
其中第一作者（通讯作者）论文被SCI收录5篇，EI收录2篇。
主持完成校级科研项目1项，承担完成教育厅自然科学专研项目1项。
主持在研校级教改项目1项，承担在研科技厅项目1项。
以第一完成人完成的科研成果获陕西省高等学校科学技术奖励三等奖1项，陕西理工学院优秀科研成果奖一等奖1项，二等奖1项。
一、.主持与承担的项目1、已完成的科研项目项目名称起止时间下达任务单位课题组排名1．宽禁带半导体中的激子与声子的相互作用（07JK207）2007.1-2008.12 陕西省教育厅第一参与人2．低维量子系统中的极化子、激子特性的研究（slg0637）2006.1-2008.12 陕西理工学院主持人3．热力学系统的平衡态及非平衡态研究（SLg0425）2005.1-2008.5 陕西理工学院第一参与人2、在研的科研项目项目名称起止时间下达任务单位经费（万元）课题组排名1．半导体量子结构中的激子效应与光学特性的研究（2009JM1012）2009.7-2011.12陕西省科技厅 4.0 第一参与人2．我校物理学“专业基础课”双语教学创新性教学模式的研究与实践（XJG1017）2010.7-2011.7 陕西理工学院0.3 主持人二、.研究成果获奖1．完成的项目《半导体量子结构中的光学声子特性和电声子相互作用性质的研究》获2009年度陕西高等学校科学技术奖三等奖，第一完成人。
2．完成的项目《半导体量子结构中的电声子相互作用性质的研究》获2009年度校级优秀科研成果奖二等奖，第一完成人。
用电化学方法还原石墨烯修饰玻碳电极来同时测定鸟嘌呤和腺嘌呤
2 设备和程序 GO表面形态的特点是通过原子力显微镜(AFM,Agilent5500, 美国)和扫描电子显微镜(SEM、日立H- 9000、日本)得到的。 所有的电化学实验都是在三电极电解池下进行的。包括 CHI660D电化学工作站(Chenhua,中国),铂电极和Ag /AgCl电极 分别作为辅助电极和参比电极。修饰电极的电化学性质是通 过循环伏安法(CV)和电化学阻抗谱(EIS)来测定的。CV是在 0.1mol/L氯化钾+ 1.0×10-3mol/L K3Fe(CN)63-/4-溶液中测定。 EIS是在0.1mol/L氯化钾+ 5.0×10-3mol/LK3Fe(CN)63--/4-溶液 中测定的。这时的平衡电势是0.175 V(vs . Ag /AgCl)、扰动振 幅为5mV，频率范围从100千赫至0.1赫兹。所有测量是在室 温下进行的(25±2 ℃)。
谢谢大家！
mol /L鸟嘌呤和腺嘌呤混合溶液 (1 : 1)的CV图 ， (c) erGO/GCE 在 0.1 mol /L PBS (pH=6.2) 在0.1 V/s的CV图
Fig. 5 (A) 在 5.0× 10-6 mol /L腺嘌呤存在时， er-GO/GCE 在0.4, 0.8, 2.0, 4.0, 8.0, 12.0,和16.0 × 10-6 mol/ L鸟嘌呤 (从a到g) 溶液的 DPV图，坐标是峰电流对鸟嘌呤浓度 (B) 在 5.0 ×10-6 mol/ L鸟嘌呤 存在时，er-GO/GCE 在0.6, 1.0, 3.0, 5.0, 7.0, 10.0, 15.0, and 20.0 × 10-6 mol /L腺嘌呤(从 a到h) 溶液 的DPV图，坐标是峰电流对腺嘌呤 浓度。
4 er-GO/GCE选择性、稳定性和重现性
材料科学与工程专业英语词汇
材料科学与工程专业英语词汇1. 物理化学物理化学是研究物质结构、性质、变化规律及其机理的基础科学，是材料科学与工程的重要理论基础之一。
物理化学主要包括以下几个方面：热力学：研究物质状态和过程中能量转换和守恒的规律。
动力学：研究物质变化过程中速率和机理的规律。
电化学：研究电流和物质变化之间的相互作用和关系。
光化学：研究光和物质变化之间的相互作用和关系。
表面化学：研究物质表面或界面处发生的现象和规律。
结构化学：研究物质分子或晶体结构及其与性质之间的关系。
统计力学：用统计方法处理大量微观粒子行为，从而解释宏观物理现象。
中文英文物理化学physical chemistry热力学thermodynamics动力学kinetics电化学electrochemistry光化学photochemistry表面化学surface chemistry结构化学structural chemistry统计力学statistical mechanics状态方程equation of state熵entropy自由能free energy化学势chemical potential相平衡phase equilibrium化学平衡chemical equilibrium反应速率reaction rate反应级数reaction order反应机理reaction mechanism活化能activation energy催化剂catalyst电池battery电极electrode电解质electrolyte电位potential电流密度current density法拉第定律Faraday's law腐蚀corrosion中文英文光敏材料photosensitive material光致变色photochromism光致发光photoluminescence光催化photocatalysis表面张力surface tension润湿wetting吸附adsorption膜membrane分子轨道理论molecular orbital theory晶体结构crystal structure点阵lattice空间群space group对称元素symmetry element对称操作symmetry operationX射线衍射X-ray diffraction2. 量子与统计力学量子与统计力学是物理学的两个重要分支，是材料科学与工程的重要理论基础之一。
绝缘体与安德森绝缘体
Thouless’ picture
A very important step to modern theory
G e 2 g ( E F ) DLd 2
e 2 hD N ( EF ) 2 h L
dimensionless
Thouless energy
ET
hD h 2 L T
2 , is level spacing, 2 is for spin 2e 2 ET E G~ g~ T h N ( EF ) ~
Question: Is the presence of electronic band gap a necessary and/or sufficient condition for the formation of insulators?
Answer: It is neither necessary nor sufficient. Counter examples: Anderson insulators: insulating states without band gap (but with a mobility gap), so that it not necessary. Superconductors: there is a electronic band gap (superconducting gap) like insulators due to electron pairing, but current can flow without resistance. Since the systems support collective excitations beside single-electronic excitations. The super-current in the system is a collective excitations.
电子受体对微生物燃料电池产电性能的影响
电子受体对微生物燃料电池产电性能的影响刘远峰;孙伟;宫磊【摘要】以厌氧污泥为接种菌源,醋酸钠为阳极基质,分别构建了铁氰化钾和过硫酸铵为电子受体的双室微生物燃料电池(MFC),并研究了MFC在不同电子受体下的产电性能.结果表明,以铁氰化钾和过硫酸铵为电子受体的MFC最大稳定输出电压均随着电子受体浓度的升高而增大.当铁氰化钾质量浓度大于2.0 g/L时,MFC最大稳定输出电压增幅不大.两种MFC的内阻均随电子受体浓度的增大而降低.阴、阳极溶液体积相等,外阻为5 000 Ω时,以10.0 g/L过硫酸铵为电子受体,MFC最大开路电压和最大输出功率密度分别为1 029.0mV和385 mW/m3;以10.0 g/L铁氰化钾作为电子受体,MFC最大开路电压和最大输出功率密度分别为711.8 mV和73 mW/m3,均小于以过硫酸铵为电子受体的最大开路电压和最大输出功率密度.因此,过硫酸铵是一种理想的电子受体,能够提高MFC产电性能.【期刊名称】《环境污染与防治》【年(卷),期】2016(038)011【总页数】6页(P84-89)【关键词】微生物燃料电池;电子受体;产电性能;降解【作者】刘远峰;孙伟;宫磊【作者单位】青岛科技大学环境与安全工程学院,山东青岛266042;青岛科技大学环境与安全工程学院,山东青岛266042;青岛科技大学环境与安全工程学院,山东青岛266042【正文语种】中文在环境污染加剧、能源紧张的今天，开发风能、太阳能、生物质能等可再生能源是解决未来能源紧张，保护环境，实现可持续发展的必由之路[1-2]。
微生物燃料电池(MFC)作为一种能够在有机废水处理过程中回收电能的最新生物处理技术，正在世界范围内引起研究人员的广泛关注,一旦实现产业化，将会给有机废水处理行业带来一次新的革命，产生不可估量的社会、环境和经济效益。
MFC是在电化学技术基础上发展起来的，以微生物为阳极催化剂，将燃料(如糖类等)的化学能直接转化为电能的装置[3-6]。
英文论文写作
❸挖掘和强调自己研究的重要性或创新性可从以下角度。 如：(1)时间问题；(2)研究手段问题；(3)研究区域问题；(4)存在不确定性； (5)研究的完全创新性（We aim to test the feasibility (reliability) of the……It is hoped that the question will be resolved with our proposed method (approach). ）
3.2 Proton transfer dynamics control the mechanism of O2 reduction by a nonprecious metal electrocatalyst. (Nature Materials, 2016, 15,754–759 )
3.3 Femtosecond control of electric currents in metallic ferromagnetic heterostructures. (Nature Nanotechnology 2016, 11,455–458)
4.4 Optimized quantum sensing with a single electronspin using real-time adaptive measurements. (Nature Nanotechnology, 2016,11,247–252)
有些表征手段或者研究方法生来就是让人膜拜的，特别是一些原位的表 征手段，能够直观地告诉人们以前得不到的一些信息。
展望我们工作的价值
Abstract写作举例（更简洁版）
二维半导体电声子相互作用
二维半导体中的电声子相互作用（Electron-Phonon Interaction）是指在二维材料中，电子与晶格振动（即声子）之间的相互耦合作用。
这种作用对材料的电子性质有着显著影响，特别是在载流子的有效质量、迁移率、超导性以及光学性质等方面。
具体来说，在二维半导体中，当电子在能带内移动时，其运动会导致晶格原子微小振动（声子激发），反过来，这些晶格振动又会改变电子的能量和动量状态。
这种动态过程通过以下几种效应体现：
1. 散射效应：电子通过与声子交换能量和动量，会发生散射，影响电子的平均自由程和迁移率。
2. 超导电性：在低温下，强的电声子相互作用可以导致BCS （Bardeen-Cooper-Schrieffer）机制下的超导现象，即电子配对形成库珀对。
3. 激子束缚：在某些情况下，电声子相互作用还可以引起电子和空穴的结合，形成激子。
4. 电子有效质量修正：由于电子与晶格相互作用，实际的电子质量会比裸电子质量大，这是因为电子需要克服晶格产生的势垒才能在能带内移动。
5. 热载流子效应：在高载流子密度或高温下，电声子相互作用将影响载流子的能量弛豫过程。
因此，深入理解二维半导体中的电声子相互作用对于优化器件性能、开发新型电子和光电子器件至关重要。
在理论研究上，通常使用量子力学的方法，如格林函数方法、第一性原理计算等来模拟和计算电声子相互作用的影响。
电热耦合
J Comput Electron(2012)11:93–105DOI10.1007/s10825-012-0387-xCoupled electro-thermal simulation of MOSFETs Chunjian Ni·Zlatan Aksamija·Jayathi Y.Murthy·Umberto RavaioliPublished online:31January2012©Springer Science+Business Media LLC2012Abstract Thermal transport in metal-oxide-semiconductor field effect transistors(MOSFETs)due to electron-phonon scattering is simulated using phonon generation rates ob-tained from an electron Monte Carlo deviceThe device simulation accounts for a full band descrip-tion of both electrons and phonons considering22types of electron-phonon scattering events.Detailed profiles of phonon emission/absorption rates in the physical and mo-mentum spaces are generated and are used in a MOS-FET thermal transport simulation with a recently-developed anisotropic relaxation time model based on the Boltzmann transport equation(BTE).Comparisons with a Fourier con-duction model reveal that the anisotropic heat conduction model predicts higher maximum temperatures because it ac-counts for the bottlenecks in phonon scattering pathways. Heatfluxes leaving the boundaries associated with differ-ent phonon polarizations and frequencies are also exam-ined to reveal the main modes responsible for transport.It is found that though the majority of the heat generation is in the optical modes,the heat generated in the acoustic modes C.Ni( )·J.Y.MurthySchool of Mechanical Engineering,Purdue University,West Lafayette,IN47907,USAe-mail:charlesni2006@J.Y.Murthye-mail:jmurthy@Z.AksamijaElectrical and Computer Engineering Department,University of Wisconsin-Madison,Madison,WI53706,USAe-mail:aksamija@U.RavaioliSchool of Electrical and Computer Engineering,University of Illinois,Urbana Champaign,IL61820,USAe-mail:ravaioli@ is not negligible.The modes primarily responsible for the transport of heat are found to be medium-to-high frequency acoustic phonon modes.Keywords Semiconductors·Dielectrics·Phonons·Boltzmann transport equation·Electron Monte Carlo device simulation·Coupled electro-thermal simulation·Micro/nanoscale heat transfer1IntroductionCoupled electro-thermal simulation of sub-micron electron device is of great interest to both academia and industry,due to the fact that self-heating may cause device performance degradation in submicron regime.Sadi et al.[1,2],used a 2-D electron Monte Carlo simulation(MC)coupled with a 2-D solution of the heat diffusion equation(HDE)to study the electrothermal phenomena in Silicon-On-Insulator(SOI) and Silicon-Germanium-on-Insulator(SGOI)metal-oxide field-effect transistors(MOSFET).Although they got in-teresting results on device thermal effects and performance degradation,there is a fundamentalflaw in their thermal so-lution of the heat diffusion equation,which is well known not valid in submicron regime[3].Raleva,Vasileska et al.[4,5],coupled electron Monte Carlo simulation with the equations for the optical and acoustic energy transfer derived from the phonon Boltzmann Transport Equation(BTE)[6].They used this methodology to study electrothermal effects in the Silicon-On-Insulator (SOI)MOSFET.They showed that the device current de-grades due to heating effects,while pronounced velocity overshoot in the nano-scale device structure(at gate length in the order of20nm)minimizes the current degradation due to lattice heating.Although they solved the equationsFig.1Phonon dispersion for bulk silicon in the X[100]direction. Phonons of the f and g type are marked on the graph[7]for the optical and acoustic energy transfer derived from phonon BTE,their thermal transfer model is a simplified model which might not be able to capture detailed physics of phonon transport in the submicron devices.To better model thermal transport in submicron devices, it is necessary to correctly resolve the granularity of phonon transport.Figure1shows phonon dispersion curves for sili-con in the[100]direction.Electron-phonon scattering scat-ters energy selectively to high-frequency optical and longi-tudinal phonon modes at the Brillouin zone edge[8–10], which then transfer energy through phonon-phonon scatter-ing processes to other phonon groups.The thermal profile in the MOSFET is thus governed by which phonon groups receive energy from electrons,how fast they scatter to other phonons,and the group velocity of these phonons.If scatter-ing from slow-moving high-frequency optical and acoustic phonons to faster-moving phonon groups is a bottle-neck, high device temperatures would occur;alternatively,if fast-moving phonons are able to move energy quickly to the de-vice boundaries,low device temperatures would result.Cap-turing these detailed physics requires a resolution not only of the electron-phonon scattering rates in both the physical and momentum spaces,but also of phonon scattering and transport mechanisms.A number of published studies have sought to simulate phonon transport at the sub-micron scale. Early studies employed a“gray”description of phonons and employed the Boltzmann transport equation(BTE)in the re-laxation time approximation[3,11].Here,all phonons are grouped into a single mode characterized by a single group velocity and relaxation time.One of the parameters,typi-cally the group velocity,is chosen to reflect that of the dom-inant phonon group responsible for transport at the device temperature,such as longitudinal acoustic(LA)phonons;the relaxation time is then computed from the bulk ther-mal conductivity.However,this type of model does not ad-equately capture the large variations in group velocity,spe-cific heat and scattering rates in MOSFET simulations.Sverdrup[12]and Ju[13]developed and improved a two-fluid or semi-gray BTE model for heat conduction in silicon-on-insulator(SOI)devices.In the two-fluid BTE model,there are two phonon modes:the reservoir mode and the propagation mode.The longitudinal acoustic phonons are lumped into the propagation mode,while the transverse acoustic and optical phonons are lumped into the reservoir mode.Heat generation due to electron-phonon interaction in MOSFET is incorporated into the reservoir mode via a source term,while the heat transport is accomplished by the propagation mode,characterized by a single group velocity. The two modes are coupled by a scattering term character-ized by a single relaxation time,again chosen to match bulk thermal conductivity.The device temperature predicted by this type of model depends strongly on the choice of the group velocity and relaxation time.If the group velocity is picked to be that of a dominant LA group,a too-long relax-ation time between reservoir and propagating modes results, leading to an unrealistically high device temperature.Because of the drawbacks of these approximate models, a number of recent efforts have sought to capture the de-tails of phonon transport,incorporating the details of phonon dispersion,polarization and scattering to different degrees. Narumanchi et al.[14,15]developed a BTE model incorpo-rating phonon dispersion effects to model MOSFET thermal transport.The phonon spectrum was resolved into bands, but only acoustic modes incorporated a ballistic term.The ballistic term was ignored for optical phonons because of their low group velocity,and a single equation for the opti-cal phonon energy was developed.The interactions among the different phonon groups were represented by frequency-dependent relaxation times,which were obtained from the perturbation theory[16].With most of the heat generation assigned to the optical phonon mode,their prediction of the hotspot temperature rise above ambient could be as high as 350%of that predicted by the Fourier diffusion model.This high number was thought to be a result of the zero group velocity assigned to the optical mode.Phonon BTE models incorporating detailed spectral reso-lution require the determination of detailed relaxation times, which can no longer be found simply by matching bulk ther-mal conductivity.Wang[17]developed a new BTE model which directly computes the scattering rate for three-phonon interactions from perturbation theory[16]without making the relaxation time approximation.All modes,including op-tical,are resolved using the BTE with ballistic terms in-cluded.Wang developed a search scheme to determine all three-phonon processes(normal(N)and Umklapp(U))con-tributing to scattering.Field effect transistor(FET)thermalmodeling using this BTE model showed that the optical phonon mode plays an important role in the prediction of the hotspot temperature,since optical phonon velocities are not negligible for intermediate wave-number values.One of the drawbacks of directly computing N and U in-teractions and enforcing conservation rules is that the com-putation of scattering rates becomes very expensive.There are many millions of N and U interactions,which must be evaluated every iteration in a typical computational process. Ni[18]developed an anisotropic relaxation time phonon BTE model based on Ref.[17].This BTE model employs a single-mode relaxation time idea,but the relaxation time is a function of the wave-vector.The model incorporates directional and dispersion behavior and the resulting three-phonon processes satisfy conservation putational expense is allayed by pre-computing single-mode relaxation times,resulting in order-of-magnitude reduction in compu-tational time over Ref.[17].A critical issue in the model development is the accounting for the role of three-phonon N scattering processes.Following Callaway[19],the over-all relaxation rate is modified to include the shift in the phonon distribution function due to N processes.The relax-ation times so obtained compare reasonably well with those extracted from equilibrium molecular dynamics simulation by Henry and Chen[20].In all the models described above,metal-oxide-semi-conductorfield effect transistor(MOSFET)modeling was undertaken by prescribing an electron-phonon scattering source in the phonon BTE.Typically,a source term is in-cluded in the optical phonon equations,or a prescribed arbi-trary distribution in wave-vector space is used.However,to fully capture the granularity of thermal transport,it is nec-essary to describe phonon generation as a function of both phonon mode and frequency.Monte Carlo simulation has long been used to model electron transport in semiconduc-tor devices[21].Pop et al.[8–10]developed a Monte Carlo simulation(e-MC)scheme to calculate Joule heating in sili-con.In their scheme,they used analytic,non-parabolic elec-tron energy bands to model electron transport,while using an isotropic,analytic phonon dispersion model for electron-phonon scattering,distinguishing optical/acoustic and lon-gitudinal/transverse phonon branches.Their Monte Carlo simulation was used to examine the details of the phonon generation spectrum by electron-phonon interaction in sili-con.They found that a significant portion of the generated phonons were optical phonons or acoustic phonons near the Brillouin zone edge.Their simulations did not focus on the details on phonon transport,however.Sinha et al.[22]developed a split-flux form of the non-equilibrium phonon BTE model in which the phonon generation spectrum was taken from Monte Carlo simula-tion of electron-phonon scattering.They split the phonon departure-from-equilibrium function into two components:one that traces the evolution of the emitted phonons before they thermalize through scattering,and another that traces the diffusion of the thermalized phonons.The former was obtained by solving the ballistic BTE in a spatial region of the order of a mean free path.The thermalized component was assumed to correspond to the solution of the BTE in the limit of diffusive transport.Rowlette and Goodson[23]coupled the electron Monte Carlo(e-MC)model of Refs.[8–10]with the split-flux model for phonon transport to perform a self-consistent sim-ulation of non-equilibrium transport in MOSFETs.Their coupled simulation begins with an isothermal e-MC simu-lation solved self-consistently with the Poisson equation in the device.The net phonon-generation rates as a function of position and phonon frequency are gathered and fed into the split-flux phonon transport model,whose solution leads to an updated distribution of phonons as a function of position. The effective temperatures for the dominant optical f-and g-type phonons as well as for the LA and TA branches are then computed and passed back to the e-MC to adjust the electron-phonon scattering rates.They used this fully cou-pled electron-phonon model to study a1-D n+/n/n+sili-con device and found that near the hotspot the temperature is anomalously high,possibly as a result of ballistic trans-port.The e-MC solver developed by Pop et al.[8–10]as-sumes analytical,non-parabolic electron energy bands and analytic phonon dispersion curves.Recently,Aksamija[7] improved an existing full-band Monte Carlo simulation tool developed at University of Illinois at Urbana-Champaign [24]to provide phonon generation terms due to electron-phonon scattering.He employed a full-band description of electrons and phonons.The electron band structure was cal-culated using the empirical pseudo-potential model of Co-hen and Bergstresser[25].The electron scattering mecha-nisms considered in Monte Carlo simulation included intra-valley acoustic phonon scattering,X–X f and g type inter-valley phonon scattering,and X–L inter-valley phonon scat-tering.The Monte Carlo simulation was performed self-consistently with a solution of the Poisson equation to up-date the electricfield during the simulation.The e-MC sim-ulation may be used to provide phonon generation rates to a phonon BTE simulation to accurately predict sub-micron thermal transport in MOSFETs.The goal of this paper is to couple the anisotropic re-laxation time phonon BTE simulation to a computation of the phonon generation spectrum calculated using the Monte Carlo simulator of Ref.[7].The Monte Carlo simulation[7] provides the phonon generation spectrum at different spa-tial positions and different positions in momentum space. The phonon generation spectrum so obtained is incorpo-rated in the anisotropic relaxation time phonon BTE model of Ref.[18]to predict more realistically the location andtemperature of a hotspot in the MOSFET device.The ap-proach taken in this paper not only improves the representa-tion of the electron-phonon scattering source to the phonon field,but also resolves the details of phonon transport more completely than in previous studies.However,only one-way coupling is considered in that the predicted temperature field does not affect electron-phonon scattering.Thus the electron mobility is not affected by the device self-heating and the drain current reduction due to self-heating is not captured.The device Monte Carlo simulation was done at fixed tem-perature of 300K.The model is applied to the prediction of the temperature field in a MOSFET and the detailed path-ways for energy transport are identified and discussed.2Phonon dispersion for siliconBulk silicon has six phonon dispersion branches:two trans-verse acoustic phonon branches (TA1and TA2),one longi-tudinal acoustic phonon branch (LA),two transverse opti-cal branches (TO1and TO2)and one longitudinal optical branch (LO).The dispersion curves for silicon used in this paper are calculated using the adiabatic bond charge model [26].A fully anisotropic Brillouin zone is taken into ac-count.3Anisotropic relaxation time modelA complete description of the anisotropic relaxation time model may be found in Ref.[18];a brief summary is given below.The phonon BTE in the energy form [18]under the single mode relaxation time assumption may be written as:∂e (r ,K ,t)∂t +∇·(e (r ,K ,t)v g )=(e 0−e(r ,K ,t))1τ3phonon +1τI +1τB+q vol (r ,K )(1a)with e (r ,K ,t)=lim3K →01(2π)1K3KωN(r ,K ,t)d 3K(1b)ande 0=lim3K →01(2π)313K3Kωexp ( ω/k B T lattice )−1d 3K(1c)Here q vol (r,K)is the volumetric heat generation term due to electron-phonon scattering.N(r ,K ,t)is the phonon oc-cupation number,and e (r ,K ,t)is the phonon energy den-sity for phonons of wave vector K at position r and time t .It denotes the phonon energy per unit physical volume per unit K-space volume at (r ,K ,t).e 0(ω)is the phonon en-ergy density corresponding to the Bose-Einstein distribution function evaluated at the lattice temperature T lattice .v g (K )is the phonon group velocity corresponding to the wave vec-tor K .It may be calculated from the phonon dispersion by v g =∇K ω(2)The adiabatic bond charge model [26]is used to com-pute the dispersion relation,as described in Ref.[18].The effective relaxation time τ(K )depends on the wave vector;a dependence on polarization is implied throughout.It con-tains the influence of three-phonon scattering,represented by a relaxation time τ3phonon and isotope scattering,repre-sented by τI ;Matthiesen’s rule [17]is applied to compute their combined influence.Boundary conditions on (1a )include the specification of thermalizing boundaries,specular boundaries or partially specular/partially diffuse boundaries.Boundary scattering is computed by representing the appropriate boundaries of the MOSFET domain as either partially or fully diffusely re-flecting.A detailed description of the treatment of boundary conditions may be found in Ref.[18].4Numerical methodEquation (1a )is discretized using the finite volume method and solved numerically.The phonon energy distribution function e (r ,K ,t)is discretized in both the spatial and wave vector domains.The spatial domain is discretized into control volumes or cells.The three-dimensional wave vec-tor space is discretized using spherical coordinates and con-sists of an angular space of 4πand a wave number space [0,K zone ],where K zone is the maximum K value in each di-rection,accounting for the shape of first Brillouin zone [18].The angular space is discretized into N θ×N φcontrol an-gles,each of extent of i ,corresponding to direction i ;θand φare the polar and azimuthal angles.The wave num-ber space is discretized into N k bands,each of extent K j ,corresponding to band j .Each polarization is discretized inthis way.The discrete energy density e ijcorresponding to direction i and band j is stored at the cell centroids.The phonon BTE is integrated over the control volume,control angle and wave number band for each polarization,resulting in an energy balance for each spatial control vol-ume for direction i ,wave number band j and polarization.A third-order SMART scheme [27]is used to discretize the convective operators.A second-order discretization of the scattering terms is used.The phonon energy densities are solved sequentially and iteratively,cycling through each di-rection and band in turn.For each direction and band,the discrete equation set is solved using the line-by-line tri-diagonal matrix algorithm (TDMA).5Lattice temperatureOnce the discrete energy density at the cell centroids is computed,the lattice temperature is determined.In order to guarantee energy conservation,the summation of the source terms on the right hand side of (1a )over all directions and bands should be zero,if q vol (r ,K )=0.The following equa-tion must be satisfied:(e 0−e (r ,K ,t)) 1τ3phonon +1τI +1τB d 3K =0(3)The lattice temperature,T lattice ,is defined so that (3)is sat-isfied,using the definition of e 0given in (1c ).6Phonon relaxation timesA key feature of the anisotropic relaxation time model is thedevelopment of single-mode relaxation rates based on a rig-orous computation of three-phonon interactions.Klemens et al.[16]developed three-phonon interaction rates based on perturbation theory.Based on these rates,Wang [17]de-veloped a full-scattering phonon BTE model which directly computes three-phonon scattering rates for N and U pro-cesses.Details may be found in Ref.[18];a brief overview is given here for completeness.Three-phonon interactions must satisfy energy and mo-mentum conservation rules,given by [16]ω+ω ↔ω (4)K +K ↔KN processesK +K ↔K +bU Processes(5)Here,ω,ω ,ω are three interacting phonons with corre-sponding wave vectors K ,K ,K ,and b is the recipro-cal lattice vector.Wang [17]developed a search techniqueto identify all possible three-phonon normal (N)and Umk-lapp (U)processes between interacting phonons.The pro-cess employs a discretization of the Brillouin zone in the manner described in this paper,and triads of interacting phonons (ij),(kl)and (mn)satisfying (4)and (5)are found.Here (i,j)denotes the direction i and wave number band j of an interacting phonon;(kl)and (mn)are interpreted in a similar fashion.Consideration of polarization in determin-ing these triads is implied.Given a such a triad,the scattering rate may be cal-culated from the perturbation theory derived by Klemens and co-workers [16,28].For an interaction of the type K +K ⇔K ,the scattering rate due to three-phonon pro-cesses is given by: dN dt 3-phonon = K2|C 3|2M ωω ωπδt (ω+ω −ω )×(NN (N +1)−(N +1)(N +1)N )(6)Here |C 3|2=(4γ23G )(M 22)(ωω ω )2,γis the Gruneisen con-stant,G is the number of atoms per unit cell,v is thesound velocity,and M is the atomic mass.N is the oc-cupation number of mode K ,while N and N are those corresponding to K and K .The summation is over all possible interactions undergone by a phonon of wave vec-tor K .The anisotropic relaxation time model employs a single-mode relaxation time approximation which signif-icantly cuts down on solution time while preserving the granularity of phonon-phonon interaction bottlenecks.Un-der this approximation,the three-phonon relaxation time τ3phonon in (1a )is computed by assuming that the only non-zero departure from equilibrium occur for the phonon mode K ,i.e.,the phonon mode for which the BTE is be-ing solved;the departure from equilibrium of phonons with wave vectors K and K are set to zero.Under this approx-imation,it is possible to show that for a single three-phonon interaction for phonon K ,the single mode relaxation time may be written as1τ3phonon (K )=2|C 3|2M ωω ωπδt (ω+ω −ω )(N 0−N0)(7)Details may be found in Ref.[18].The computational savings afforded by the anisotropic relaxation time model now become evident.To evaluate the scattering rate in (6),the non-equilibrium distribution func-tions N,N and N are necessary.These change iteration-to-iteration in a typical computational procedure.Since there may be many millions of N and U interactions,the scattering term update becomes computationally very ex-pensive even for coarse spatial meshes.On the other hand,τ3phonon in (7)depends only on the equilibrium distributions of the interacting phonons,and may be computed a priori and stored,greatly reducing the cost per iteration.In the present implementation,a list of all permitted three-phonon N and U processes is first determined using the procedure described in Wang [17].Based on these per-mitted interactions,a single-mode relaxation time as a func-tion of discrete wave vector,polarization and temperature is computed and stored in a look-up table.Interpolations within this look-up table are used to compute the distribu-tions of relaxation time in physical and wave-number space in the MOSFET simulation.Incorporation of N processes is performed through the use of a shifted equilibrium distribu-tion,as described by Callaway [19].Details of the relaxation time computations as well as validation against experimen-tal measurements may be found in Ni [18].7Monte Carlo simulation including full phonon dispersionJoule heating or phonon generation in the device due to electron-phonon interaction may be obtained from Monte Carlo simulation.A three-dimensional ensemble Monte Carlo simulator with a self-consistent non-linear Poisson solver[29]is employed here;a quantum correction based on thefirst moment of the Wigner equation is used[7].The Monte Carlo simulator accounts for a full band structure for electrons which was implemented in[30].The6X valleys of the lowest electron conduction band at(±0.85×2π/a,0,0),(0,±0.85×2π/a,0),and (0,0,±0.85×2π/a)in the wave vector space(a is the lat-tice constant of bulk silicon[7]),and the next higher L val-leys in the conduction band,are considered.The transitions may be categorized into the following types:intra-valley transitions(within one X valley),inter-valley X–X f type transitions(between a valley and any of the four valleys closest to it),inter-valley X–X g type transitions(between a valley and its opposite valley),and inter-valley X–L transi-tions.Figure1shows the f and g type transitions graphically.A g-type transition,for example,involving electrons go-ing from(0.85×2π/a,0,0)to(−0.85×2π/a,0,0)would cause a phonon at(1.7×2π/a,0,0)to be generated.In the irreducible wedge of thefirst Brillouin zone,the correspond-ing K value would be(0.3×2π/a,0,0)[7].All the other g type transitions may be obtained exploiting the symmetry of the lattice.The energies of the phonons involved in each transition may be tabulated and used to simplify the scattering rate calculation in the Monte Carlo simulation.As mentioned above,four types of transitions,i.e.,intra-valley,X–X f type, X–X g type,and X–L inter-valley transitions,are consid-ered.For each type of transition,there are several phonon branches on which phonons may be emitted or absorbed.A total of22different kinds of scattering events resulting from these interactions are shown in Table1.The transition rates or probabilities are tabulated for these22scattering events in the Monte Carlo simulator.The scattering prob-abilities are also tabulated in the Monte Carlo simulator by the energy of the electron involved in the events listed in Ta-ble1.They are calculated by analytically integrating Fermi’s Golden Rule over all initial electron momenta k with a given energy and all the possiblefinal momenta k [7].Whenever a collision,resulting in either emission or ab-sorption,occurs,an average phonon energy corresponding to the chosen event type is either subtracted(for emission)or added(for absorption)to the current electron energy.These energies are listed in Table1.Thefinal energy of the elec-tron is then used to look up thefinal state of the electron after collision in a table of electron momenta sorted by energy in the irreducible wedge of thefirst Brillouin zone.Then the Table1Classification of scattering events[7]Event Valley Sign Branch EnergyE avg(meV)1Acoustic Absorption TA/LA0to45meV 2Intra-valley Emission TA/LA0to45meV 3Absorption TA18.95824LA/LO47.39545X–X f TO59.02886TA12.06437LA18.52738X–X g TO/LO62.04499X–X f Emission TA18.958210LA/LO47.395411TO59.028812X–X g TA12.064313LA18.527314LO/TO62.044915X–L Absorption TO57.908516LO54.634017LA41.363218TA16.976219X–L Emission TO57.908520LO54.634021LA41.363222TA16.9762 actualfinal state in the complete3-D momentum space is chosen randomly by symmetry considerations,according to the specific type of scattering that occurred[31].For exam-ple,for X–X f type scattering,the largest component of the momentum in thefinal state must be made perpendicular to the largest component of the momentum in the initial state, while other types of scattering may have their signs and or-dering chosen at random[7].A full phonon dispersion relation,calculated from the adiabatic bond charge model[26]and tabulated for look-up, is included to ensure accuracy.An iterative algorithm intro-duced by Pop et al.[8]is adapted to ensure that all scatter-ing events conserve energy and momentum with the use of the full phonon dispersion relationship.As shown in Fig.2, this algorithm starts at each scattering event with an estimate of the phonon energy,E est,involved.This estimated energy is taken from those listed in Table1(E est=E avg).From the resulting electron energy E(k )=E(k)±E avg,thefinalstate k is looked up,and the phonon momentum K is de-termined by K=k±k .Its corresponding phonon energy E(K)is determined from the full phonon dispersion rela-tion and used as the next guess of the electronfinal energy E(k )=E(k)±E(K).Thefinal state k is again looked up and the procedure described above repeated until afi-nal state satisfying both momentum and energy conserva-。
溶剂极性对β胡萝卜素分子电子-声子耦合的影响
溶剂极性对β胡萝卜素分子电子-声子耦合的影响徐胜楠;孙美娇;孙尚;刘天元;朱坤博;孙成林;里佐威【摘要】引用一种带有量纲的电子-声子相互作用常数,很容易建立它与黄昆因子的关系式,进而计算出类胡萝卜素分子每个碳碳振动模的电子-声子耦合常数.测量了β胡萝卜素分子在极性溶剂1,2-二氯乙烷和非极性溶剂环己烷中20～60℃的温度范围内紫外-可见吸收光谱和共振拉曼光谱.结果表明,在极性溶剂1,2-二氯乙烷中,β胡萝卜素分子的碳碳键拉曼散射截面小,黄昆因子、电子-声子耦合数比非极性溶剂中大.为了解释这种现象,我们引入线性多烯分子的两种模型,即F A C Oliveria引入的有效共轭长度模型和D Yu Paras-chuk提出的相干弱阻尼电子-晶格振动模型.【期刊名称】《发光学报》【年(卷),期】2013(034)010【总页数】7页(P1373-1379)【关键词】黄昆因子;电子-声子耦合系数;线性多烯【作者】徐胜楠;孙美娇;孙尚;刘天元;朱坤博;孙成林;里佐威【作者单位】吉林大学超硬材料国家重点实验室,吉林长春130012;吉林大学物理学院,吉林长春130012;吉林大学物理学院,吉林长春130012;吉林大学物理学院,吉林长春130012;吉林大学物理学院,吉林长春130012;吉林大学物理学院,吉林长春130012;吉林大学物理学院,吉林长春130012;吉林大学物理学院,吉林长春130012【正文语种】中文【中图分类】O443.41 引言β 胡萝卜素是类胡萝卜素之一，它是一种线性链状多烯类生物分子，分子中含有π 电子共轭双键。
在高科技领域，β 胡萝卜素可以用来制造高速开关、分子导线等光电器件;在医学方面，它有防癌和抗癌的作用;在生物学方面，它的光采集、光防护功能也十分突出［1-6］。
β 胡萝卜素具有良好的光学特性，它吸收400～500 nm 的光，从1Ag1(S0)基态跃迁到1Bu+(S2)激发态，然后再快速从S2态到21Ag+(S1)激发态，这一过程完成光合作用和猝灭单态氧［7］。
SCI科技论文写作常用句型大全
一．好的论文题目是成功的一半好的论文，每一个部分都需要精雕细琢。
我们先来看看Science, Nature 子刊上用的都是些什么题目，到底这些题目暗含哪些玄机？以下是从2016年发表的论文中随机挑选的一些题目，我将其做了一下简单的分类：?reduction1. Water splitting–biosynthetic system with CO2efficiencies?exceeding?photosynthesis. (Science, 2016, 352, 1210)类似: Scalable water splitting on particulate photocatalyst sheets with a solar-to-hydrogen energy conversion efficiency?exceeding?1%?(Nature Materials 2016,15,611-615)这种题目适合哪类文章？适合于那种性能极其显着的文章（可以创纪录的文章），比如说Nocera et al. 的?Science, 2016, 352, 1210，直接与光合作用进行对比，给人的震撼是非常强的。
这种对比效果能够一下子抓住人们的眼球，吸引着读者进行阅读。
要点：使用这样的题目首先你的实验结果得够牛，你对于实验结果要足够自信，对于背景知识的了解得要足够深。
因为取这样的题目意味着你要真正达到了某一个高度。
如果明明有很多大海在那里，你个小池塘和小水坑进行比较，那么会闹笑话的。
2.1 Quantifying?the promotion of Cu catalysts by ZnO for methanol synthesis (?Science,2016, 352, 969-974.)2.2?Exploring?the origin of high optical absorption in conjugated polymers. (Nature Materials 2016,?DOI:?10.1038/nmat4645?)2.3 Promoting?solution phase discharge in Li–O2 batteries containing weakly solvatingelectrolyte?solutions (Nature Materials 2016, DOI: 10.1038/nmat4629)2.4 Reconstructing?solute-induced phase transformations within individual nanocrystals (NatureMaterials 2016,?doi:10.1038/nmat4620)2.5 Tailoring?the nature and strength of electron–phonon interactions in the SrTiO3(001) 2D electron?liquid (Nature Material, 2016, doi:10.1038/nmat4623)我简单地检索了下Nature Materials上面的文章题目，发现这种类型的题目真的非常多。
电子束辐照与邻酪氨酸产率的剂量关系
电子束辐照与邻酪氨酸产率的剂量关系张丹丹;王欣欣【摘要】阐明了辐照剂量与邻酪氨酸转化率的关系.以邻酪氨酸的前体苯丙氨酸为研究对象,给予不同电子束辐照剂量,使用液相色谱-串联质谱联用法同时测定3种酪氨酸同分异构体和苯丙氨酸,探讨了在无基质干扰条件下辐照剂量与邻酪氨酸转化率的关系,以及苯丙氨酸在不同辐射剂量下转化为邻酪氨酸的效率.结果表明:在辐照剂量为1~10 kGy时,邻酪氨酸的转化率为0.019%~0.105%,远高于样品基质中邻酪氨酸的转化率.%In this study ,the relationship between the contents of o-tyrosine in phenylalanine and the electron beam irradiation dose was studied .Phenylalanine ,as the precursor of o-tyrosine ,was irradiated by electron beam with different irradiated dose ,then a stable LC-MS/MS method was developed for the simultaneous determination of three tyrosine isomers and phenylalanine ,the relationship between the irradiation dose and o-tyrosine content was investigated without the interference of matrix ,and the efficiency of phenylalanine conver-sion to o-tyrosine was analyzed under different irradiation doses .The results showed that the conversion of phenylalanine to o-tyrosine at different irradiated dose was of 0.019% —0.105% at 1—10 kGy dose in a dose-dependent manner ,much more higher than that in sea-food which indicated that the matrix of seafood would produce effect on the conversion of phenylalanine to o-tyrosine .【期刊名称】《青岛科技大学学报（自然科学版）》【年(卷),期】2017(038)005【总页数】4页(P36-39)【关键词】辐照剂量;邻酪氨酸;苯丙氨酸;转化;液相色谱-串联质谱联用法【作者】张丹丹;王欣欣【作者单位】青岛科技大学化工学院 ,山东青岛 266042;青岛科技大学化工学院 ,山东青岛 266042【正文语种】中文【中图分类】O657.6;O657.7Abstract: In this study, the relationship between the contents of o-tyrosine in phenylalanine and the electron beam irradiation dose was studied. Phenylalanine, as the precursor of o-tyrosine, was irradiated by electron beam with different irradiated dose, then a stable LC-MS/MS method was developed for the simultaneous determination of three tyrosine isomers and phenylalanine, the relationship between the irradiation dose and o-tyrosine content was investigated without the interference of matrix, and the efficiency of phenylalanine conversion to o-tyrosine was analyzed under different irradiation doses. The results showed that the conversion of phenylalanine to o-tyrosine at different irradiated dose was of 0.019%—0.105% at 1—10 kGy dose in a dose-dependent manner, much more higher than that in seafood which indicated that the matrix of seafood would produce effect on the conversion of phenylalanine to o-tyrosine.Key words: irradiation dose; o-tyrosine; phenylalanine; conversion; liquid chromatography- tandem mass spectrometric电子束辐照作为一种防止细菌性腐败和降低致病菌所致风险的方法，受到越来越多的关注[1-3]。
高温超导材料晶格振动相互作用机制揭示
高温超导材料晶格振动相互作用机制揭示高温超导材料是一类在相对较高温度下表现出极低电阻和完美输运电流的材料。
其研究对于理解超导机制以及应用于能源传输和储存领域具有重要意义。
然而，高温超导材料的超导机制仍然存在许多未解之谜。
其中一个重要的研究方向是探究晶格振动与超导特性之间的相互作用机制。
晶格振动主要由声子（phonon）模式来描述，而在高温超导材料中，超导性的产生与电子-声子相互作用是密切相关的。
在超导材料中，声子的存在可以改变电子的运动和电子之间的相互作用，从而影响超导性能。
因此，理解晶格振动与超导性之间的关系对于揭示高温超导材料的机制具有重要意义。
实验观测结果表明，在高温超导材料中，晶格振动谱与其超导特性之间存在紧密关联。
具体而言，多种声子模式的强化或减弱与超导转变温度之间存在相关性。
这表明晶格振动通过与电子的相互作用激发超导性。
事实上，电子之间的库仑相互作用和电子与晶格之间的相互作用是形成超导态的必要条件。
近年来，通过研究各类高温超导材料，科学家们逐渐揭示了晶格振动与超导性之间的一些机制。
一个重要的发现是，强耦合区与铁基和铜基高温超导材料中的晶格振动有着紧密的联系。
在这些材料中，晶格振动通过增强电子之间的相互作用来支持超导性。
这种相互作用可以通过具有不同能量尺度的声子模式来实现。
一种重要的声子模式是铁基高温超导材料中的旋转声子（spin fluctuations），这是由电子自旋引起的晶格振动。
旋转声子的存在导致了超导性的出现。
实验观测表明，旋转声子强度的增强与超导转变温度的提高之间存在紧密关联。
这表明旋转声子的存在是铁基高温超导材料中超导机制的一个重要组成部分。
除了旋转声子，铜基高温超导材料中的铜氧平面弛豫模式（Cu-O plane breathing mode）也被认为在超导机制中起重要作用。
这种声子模式描述了铜氧平面中铜离子和氧离子的相互相对移动。
实验观测表明，铜氧平面弛豫模式的能量和强度与超导转变温度之间存在关联。
一氧化碳离子基态光谱性质的同位素效应研究
2008年2月绵阳师范学院学报Feb．，2008第27卷第2期Journal of M i a n y a n g N o r m M U ni v e r s it y V01．27N o．2一氧化碳离子基态光谱性质的同位素效应研究韩彩霞1，刘国跃2’’(1．西华师范大学物理与电子电子信息学院，IⅡI Jtl南充637002；2．绵阳师范学院理论物理研究所，四川绵阳621000)摘要：采用H er z l)e rg的同位素理论研究了一氧化碳离子基态光谱性质的同位素效应，研究了同位素效应对分子结构性质在振动能级、力常数等方面的影响，得到了实验缺乏的廿C160+基态的光谱常数a。
结果表明，ncl6 0+基态与12C160+基态的光谱性质较好符合Herdaerg同住素理论的预计，振动能级、力常数理论预计非常接近实验结果。
关键词：CO+；基态；光谱性质；同住素效应中图分类号：056l；0641 文献标识码：A 文章编号：1672-612x(2008)02-0043-041 引言双原子分子离子XY+的光谱数据反映了分子结构性质的基本和详细信息，光谱数据对于确定分子离子中原子与离子间的相互作用和振动能级非常重要。
现代光谱技术的发展，已能测得精确度很高的分子光谱数据，为研究分子结构和性质提供了很好的基础。
CO+光谱数据常常作为环境和燃烧过程监视的重要线索心J。
在等离子体放电、半导体刻饰和工业废气等离子体无害化处理过程中，也起着重要作用，CO+的光谱研究有助于等离子体物理和相关技术的发展13J。
对12c16D+光谱数据观测的首次报道是在1909年H J，1932年，Menton等人发表了该带系A2Ⅱ一r∑+的天文观测结果"J，1960年Shvangiaadze等人研究了心C160+的矿∑+一r∑+跃迁的光谱数据蹲】，直到最近，都还有关于CO+光谱数据观测和结构性质研究的报道，2003年，R．Kepe等人又对其他跃迁的光谱数据进行了研究¨J。
电子声子相互作用对Graphene能带的修正
电子声子相互作用对Graphene能带的修正龙明生;岑燕君;李铭【摘要】研究了电子声子相互作用对Graphene电子能带的影响,把电子和LO光频声子相互作用当作微扰,用微扰论方法计算了电子声子相互作用对电子能带的修正. 计算结果表明,在费米面附近,Graphene电子能带下移,电子费米速度下降.计算结果和实验测量基本符合.【期刊名称】《华南师范大学学报（自然科学版）》【年(卷),期】2010(000)002【总页数】4页(P55-58)【关键词】单层石墨;电子声子相互作用;能带结构【作者】龙明生;岑燕君;李铭【作者单位】华南师范大学物理与电信工程学院,广东广州,510631;华南师范大学物理与电信工程学院,广东广州,510631;华南师范大学物理与电信工程学院,广东广州,510631【正文语种】中文【中图分类】O469Graphene是最近新发现的一种由单层石墨构成二维晶体材料[1]．以前，人们认为二维碳原子层在现实中是不可能存在的，即使分离石墨层的力不损伤石墨层，石墨自身的热释放也会像焚纸一样摧毁石墨层．但是2004年《Science》上的一篇文章报道A.K.Geim等人成功分离出了单层石墨层，证实了这种二维材料是可以稳定存在的[2-3]．他们用一种类似于“削铅笔”的方法，制成了单层碳原子层，制造出了Graphene这种材料．Graphene这种新材料的独特性质引起了国际上材料学界的广泛关注．Graphene是一层按照蜂窝状晶体点阵排列的碳原子[4]．它呈二维层状结构，如图1(a)所示．其点阵并不是完全平坦的，而是有小的起伏[5]．Graphene晶体点阵的每个元胞包含2个碳原子，如图1(a)中阴影区所示. 相邻碳原子通过SP2杂化轨道形成价键．Graphene的能带结构如图1(b)所示．由图可见，在布里渊区的6个顶角上，Graphene的价带与导带点连通.这些顶角附近的能带呈线性色散关系[6]，如图1(b)中放大后的插图所示．这些顶角称为狄拉克点[7]. 载流子的有效质量在狄拉克点附近消失．这正是Graphene的奇特性质的根源．由于Graphene能带在狄拉克点附近的线性关系，Graphene具有许多奇特的物理性能．首先，载流子的速度接近光速以及无质量的特性使Graphene成为研究相对论效应的一种理想材料．此外，Graphene中的电子运动速度高，迁移率高，可以用来制造高速响应的电子器件．目前,曼彻斯特大学的研究人员用graphene制造出了可以在常温下运行的单电子晶体管(SET)的模型[8]．这种晶体管只有1个原子层厚、10个原子宽，给半导体工业带来了一个新的发展机遇．研究人员估计，如果能去除材料中的杂质，Graphene可望在室温下实现高达200 000 cm2/Vs的电子迁移率，比硅材料高大约100倍．最近，人们还发现Graphene材料在室温下出现量子霍尔效应[9-10]，对研究量子现象有重要价值．Graphene产生奇特电子特性的原因是其特殊的能带结构．费米面附近的能带直接影响材料的性质．研究表明，电子声子相互作用对能带结构有显著的影响，尤其是会显著降低电子迁移率．因此，研究Graphene材料中电子声子相互作用对材料电子性质的影响有重要的应用价值．由于电子声子相互作用，狄拉克点附近的能带结构不再保持严格的线性关系．本文用二级微扰处理电子声子相互作用，计算电子声子相互作用对能带的影响．Graphene元胞中的2个碳原子A和B相对运动，产生极化电场对晶体中传导电子产生电磁作用．纵光频声子(LO)比纵声频声子[11]对传导电子的作用强得多．因此，本工作主要考虑LO声子对晶体中载流子能带的影响．由于电声子相互作用相对于电子之间的相互作用较弱，计算时电声子相互作用可以当作微扰处理．在长波近似下LO声子的位移场可写为[11]W(r)=(uA(r)-uB(r))=其中eq为极化矢量，uA(r)、uB(r) 分别为A、B 原子偏离平衡位置的位移，M为折合质量为声子的产生湮灭算符，ωL为LO声子圆频率．位移场给出的极化电场为其中常量F由利顿-萨克斯-特勒关系式给出:其中ε∞为高频介电常数，ε0为静态介电常数．用二次量子化表示的电势为).在自由电子近似下，电子声子相互作用的哈密顿量为其中为电子的产生湮灭算符．在Graphene能带中的狄拉克点附近，没有电子声子相互作用的哈密顿量为导带能量为其中vf为费米速度，Q是狄拉克点的波矢．当温度为0K时，设导带底部|k〉状态上有一个电子，声子处于真空态|0〉，没有电子声子相互作用时系统的状态为|k;0〉=0〉=0q〉.由于电子与声子相互作用比较弱，用微扰理论计算Hep对Graphene中狄拉克点附近电子的能量修正为它代表电子先发射q声子，然后再吸收同一声子的自能过程，其中求和禁止分母为0的q．根据我们可求得因此当k′≪q时，我们可以作近似≈q-k′ccos θ，得当k′≪q时≪1．准至二阶--．把这个近似值带入Ek并积分得Ek=ln=其中狄拉克点附近电子能带向下移动β，费米速度下降,由vf变为(1-α)vf．式(14)说明电子与LO声子相互作用使电子能带下移β，狄拉克点附近电子的费米速度vf减小为原来的1-α倍．狄拉克点附近能带发生弯曲如图2(a)所示．这个结果与如图2(b)所示的实验结果[12]基本一致．实验结果表明，能带整体下移0.5 eV，在费米面上出现拐点，斜率变小．目前还没有Graphene的高频介电常数的实验数据．根据实验数据可以反推出高频介电常数等重要参数．计算结果表明，电子声子相互作用正确地解释了Graphene电子能带在费米面附近偏离线性色散关系的性质．电子声子相互作用对电子能带有明显的影响，引起电子能带下移，电子费米速度下降．在有限温度下，电子声子相互作用的影响还会更显著．本文研究了电子声子相互作用对Graphene电子能带的影响，把电子和LO光频声子相互作用当作微扰，用微扰论方法计算了电子声子相互作用对电子能带的修正．计算结果表明，电子声子相互作用导致Graphene电子能带下移，电子费米速度下降．计算结果和实验结果基本符合．致谢作者衷心感谢胡梁宾教授的有益讨论．Key words： graphene; electron-phonon interaction; energy band【相关文献】[1] NOVOSELOV K S, GEIM A K, MOROZOV S V, et al. Electric field effect in atomically thin carbon films[J]. Science, 2004, 306: 666-669.[2] NOVOSELOV K S, JIANG D, BOOTH T, et al.Two-dimensional electron and hole gases at the surface of graphite[J]. Phys Rev B, 2005, 72: 201401(1-4).[3] NOVOSELOV K S, GEIM A K, MOROZOV S V, et al. Magnetoelectronic properties inlow-dimensional graphene systems[J]. Nature, 2005,438: 197-200.[4] PERES N M R, GUINEA F, CASTRONETO A H. Electronic properties of disordered two-dimensional carbon[J]. Phys Rev B, 2006, 73: 125411(1-23).[5] MEYER J C, GEIM A K, KATSNELSON M I. The structure of suspended graphene sheets[J]. Nature, 2007, 446:60-63.[6] ZHOU S Y, GWEON G H, GRAF J, et al. First direct observation of Dirac fermions in graphite[J]. Nature Physics, 2006, 2: 595-599.[7] SLONCZEWSKI J C, WEISS P R. Band structure of graphite[J]. Phys Rev, 1958, 109:272-279.[8] GEIM A K, NOVOSELOV K S. The rise of graphene[J]. Nature Materials, 2007, 6: 183-191.[9] ABANIN A, NOVOSELOV K S, LEE P A, et al. Dissipative quantum hall effect in graphene near the Dirac point[J]. Phys Rev Lett, 2007, 98: 196806(1-4).[10] ZHANG Y, TAN Y W, STORMER H L, et al. Experimental observation of the quantum Hall effect and Berry’s phase in graphene[J]. Nature, 2005,438: 201-204.[11] 李正中. 固体理论[M]. 北京：高等教育出版社，2003：148-150.[12] BOSTWICK A, OHTA T, SEYLLER T, et al. Quasiparticle dynamics in graphene[J]. Nature Physics, 2007, 3: 36-40.。
物理专业英语词汇(E)
物理专业英语词汇(E)e layer e 层e process e 过程eagle mounting 伊格尔光栅装置early type stars 早型星earnshaw theorem 厄钉定理earphone 耳机earth 地球earth bar 接地棒earth capacity 大地电容earth currents 大地电流earth ellipsoid 地球椭球earth magnetic field 地磁场earth magnetic pole 地磁极earth observation satellite 地球观测卫星earth plate 接地导板earth potential 大地电位earth satellite 地球卫星earth science 地球科学earth spheroid 地球偏球体earth's atmosphere 地球大气earth's magnetic field 地磁场earth's magnetic pole 地磁极earth's magnetism 地磁earth's mantle 地幔earth's oblateness 地球偏率earth's surface 地表earthing 接地earthquake 地震earthshine 地照earthtremors 地震east longitude 东经ebert fastie mounting 埃贝特法斯铁装置ebonite 硬橡胶ebullition 沸腾eccentric anomaly 偏近点角echelette 红外光栅echelette grating 红外光栅echelle 中阶梯光栅echelle spectroscope 中阶梯光栅分光镜echo 回声echo ranging 回波测距echo sounder 回声探测器echo sounding 回声探测echo suppressor 回声抑制器eclipse 食eclipsing binary 食双星eclipsing variable 食双星ecliptic 黄道ecliptic coordinates 黄道坐标ecliptic plane 黄道面economizer 节能器eddington limit 埃丁顿极限eddy 涡流eddy current 涡流eddy current loss 涡琉耗eddy currents 涡电流eddy diffusion 涡俩散eddy field 旋涡场eddy flow 涡流eddy friction 涡动摩擦eddy motion 涡旋运动eddy viscosity 涡动粘性edge dislocation 边缘位错edge effect 边缘效应edge focusing 边缘聚焦edge tone 边棱音edison effect 爱迪生效应effective area 有效面积effective atomic number 有效原子序数effective charge 有效电荷effective cross section 有效截面effective current 有效电流effective differential cross section 有效微分截面effective dose equivalent 有效剂量当量effective g value 有效 g 值effective head 有效落差effective height 有效高度effective impedance 有效阻抗effective inductance 有效电感effective interaction 有效相互酌effective magnetic field 有效磁场effective mass 有效质量effective multiplication factor 有效倍增因数effective power 有效功率effective pressure 有效压力effective pyranometer 地面辐射表effective quantum number 有效量子数effective radiation 有效辐射effective range 有效射程effective resistance 有效电阻effective temperature 有效温度effective value 有效值effective voltage 有效电压effective wavelength 有效波长efficiency 效率efflux velocity 喷气速度effusion 泻流ehrenfest theorem 厄伦费斯脱定理eia standard eia 标准eigenfrequency 本盏率eigenfunction 特寨数eigenmode 固有模式eigenrotation 固有转动eigenstate 本宅eigenvalue 本盏eigenvector 本崭量eigenvlaue problem 本盏问题eight vertex model 八顶点模型eightfold way 八维法eikonal 程函eikonal approximation 程函近似einstein 爱因斯坦einstein de broglie formula 爱因斯坦德布罗意公式einstein de haas effect 爱因斯坦德哈斯效应einstein de sitter universe 爱因斯坦德呜宇宙einstein equation 爱因斯坦方程einstein shift 爱因斯坦位移einstein tower 爱因斯坦塔einstein universe 爱因斯坦宇宙einstein's formula for specific heat 爱因斯坦比热公式einstein's relation 爱因斯坦关系einstein's transition probability 爱因斯坦跃迁概率einsteinium 锿ejection 放射ejector 喷射器ejector vacuum pump 喷射真空泵ekman layer 埃克曼层elastance 倒电容elastic 弹性的elastic after effect 弹性后效elastic anisotropy 弹性蛤异性elastic body 弹性体elastic coefficient 弹性常数elastic collision 弹性碰撞elastic compliance 弹性柔量elastic constant 弹性常数elastic deformation 弹性形变elastic energy 弹性能elastic equilibrium 弹性平衡elastic fatigue 弹性疲劳elastic force 弹力elastic hysteresis 弹性滞后elastic limit 弹性极限elastic manometer 弹性压力计elastic modulus 弹性模数elastic plastic deformation 弹塑性畸变elastic relaxation 弹性弛豫elastic scattering 弹性散射elastic scattering cross section 弹性散射截面elastic stability 弹性稳定性elastic surface wave device 弹性表面波设备elastic vibration 弹性振动elastic wave 弹性波elasticity 弹性elasto plastic deformation 弹塑性变形elastodynamics 弹性力学elastomer 弹性体elastoplastic wave 弹塑性波elastoviscoplasticity 粘弹可塑性electret 永电体electric 电的electric arc 电弧electric balance 电力秤electric bell 电铃electric calorimeter 电量热器electric capacity 电容electric charge 电荷electric circuit 电路electric clock 电钟electric conduction 电导electric conductor 导电体electric convection current 对羚流运羚流electric current 电流electric dipole 电偶极子electric dipole moment 电偶极矩electric dipole radiation 电偶极辐射electric discharge 放电electric discharge lamp 放电灯electric displacement 电移electric double layer 双电荷层electric field 电场electric field strength 电场强度electric force 电力electric furnace 电炉electric heater 电热器electric image 电象electric lamp 电灯electric lighting 电气照明电照electric line of force 电力线electric machine 电机electric micrometer 电测微计electric moment 电矩electric motor 电动机electric multipole radiation 电多极辐射electric musical instrument 电乐器electric noise 电噪声electric oscillation 电振荡electric potential 电势electric power 电功率electric quadrupole moment 电四极矩electric refrigerating element 电致冷元件electric resistance 电阻electric spark 电火花electric susceptibility 电极化率electric vector 电矢electric wave 电波electric welding 电焊electric wind 电风electric wire 电线electrical 电的electrical double layer 双电荷层electrical engineering 电工学electrical measuring instrument 电测量仪表electrical neutral axis 电中性线electrical pulse 电脉冲electrical resonance 电共振electrical thermometer 电温度表electricity 电electrification 电气化;带电electro discharge machining 放电加工electro rheological fluid 电龄学铃electroacoustic transducer 电声转换器electroacoustics 电声学electrocapillarity 电毛细酌electrochemical 电化学的electrochemical constant 电化学常数electrochemical equivalent 电化当量electrochemical polarization 电化学极化electrochemical potential 电化电势electrochemistry 电化学electrode 电极electrode potential 电极电位electrodynamic 电动力学的electrodynamics 电动力学electroendosmosis 电内渗electrography 电子照相法electrohydrodynamics 电铃动力学electrokinetic phenomenon 电动学现象electrokinetic potential 电动学电位electrokinetics 电动学electroluminescence 电发光electrolysis 电解electrolyte 电解质electrolytic condenser 电解电容器electrolytic conduction 电解导电electrolytic corrosion 电化腐蚀electrolytic polarization 电解极化electrolytic polishing 电解抛光electrolytic semiconductor 电解半导体electrolytic solution 电解液electromagnet 电磁铁electromagnetic 电磁的electromagnetic constant 电磁常数electromagnetic coupling 电磁耦合electromagnetic effect 电磁效应electromagnetic energy 电磁能electromagnetic field 电磁场electromagnetic flowmeter 电磁量计electromagnetic force 电磁力electromagnetic horn 电磁喇叭electromagnetic induction 电磁感应electromagnetic interaction 电磁相互酌electromagnetic lens 电磁透镜electromagnetic mass 电磁质量electromagnetic mass separator 电磁质量分离器electromagnetic momentum 电磁动量electromagnetic oscillations 电磁振荡electromagnetic oscillograph 电磁式示波器electromagnetic pump 电磁泵electromagnetic radiation 电磁辐射electromagnetic scattering 电磁散射electromagnetic shielding 电磁屏蔽electromagnetic system of units 电磁单位制electromagnetic unit 电磁单位electromagnetic wave 电磁波electromagnetics 电磁学electromagnetism 电磁electromechanical analogy 机电模拟electromechanical transducer 机电转换器electrometer 静电计electrometer tube 表用管electromotive force 电动势electron 电子electron accelerator 电子加速器electron affinity 电子亲和力electron attachment 电子附着electron avalanche 电子雪崩electron beam 电子束electron beam machining 电子束加工electron beam pumped laser 电子束激励激光器electron capture 电子俘获electron channeling 电子沟道效应electron cloud 电子云electron concentration 电子浓度electron correlation 电子关联electron current 电子流electron cyclotron resonance heating 电子回旋共振加热electron density 电子密度electron diffraction 电子衍射electron diffraction camera 电子衍射摄象机electron diffraction pattern 电子衍射图样electron donor acceptor complex 电子施周昼合物electron emission 电子发射electron energy loss spectroscopy 电子能量损失能谱法electron gas 电子气electron hole 电子空穴electron hole pair 电子空穴对electron holography 电子线全息学electron impact 电子撞击electron impact spectroscopy 电子撞烩谱学electron interferometer 电子干涉仪electron isomerism 电子同质异能性electron lens 电子透镜electron linac 电子直线加速器electron linear accelerator 电子直线加速器electron mass 电子质量electron microscope 电子显微镜electron migration 电子移动electron mirror 电子镜electron multiplier 电子倍增器electron neutrino 电子中微子electron nuclear double resonance 电子核双共振electron optical 电子光学的electron optics 电子光学electron orbit 电子轨道electron pair 电子对electron pair bond 电子对键electron phonon interaction 电子声子相互酌electron physics 电子物理学electron plasma 电子等离子体electron plasma wave 电子等离子波electron positron collision 电子正电子碰撞electron positron field 电子正电子场electron positron pair 电子正电子对electron rays 电子射线electron ring accelerator 电子环加速器electron scattering 电子散射electron shell 电子壳electron shell structure 电子壳层结构electron source 电子源electron spectroscopy 电子光谱学electron spectrum 电子能谱electron spin 电子自旋electron spin double resonance 电子自旋双共振electron spin resonance 电子自旋共振electron synchrotron 电子同步加速器electron telescope 电子望远镜electron temperature 电子温度electron theory 电子论electron theory of metals 金属电子论electron transit time 电子转移时间electron trap method 电子陷阱法electron traps 电子陷阱electron tube 电子管electron volt 电子伏特electron wave 电子波electronegative 阴电性的electronegative element 阴电性元素electronegative gas 阴电性气体electronegativity 负电性electronic 电子的electronic band spectrum 电子带谱electronic charge 电子电荷electronic configuration 电子组态electronic impact 电子撞击electronic lens 电子透镜electronic mail 电子邮政electronic musical instrument 电子乐器electronic polarization 电子极化electronic relay 电子继电器electronic state 电子态electronic structure 电子结构electronic switch 电子开关electronic transition laser 电子跃迁激光器electronics 电子学electrooptic crystal 电光晶体electroosmosis 电内渗electrophoresis 电泳现象electrophoretic currents 电泳电流electrophoretic mobility 电泳迁移率electrophoretic potential 电泳电位electrophorus 起电盘electrophotography 电子照相法electroplating 电镀electropositive 阳电性的electropositive element 阳电性元素electroscope 验电器electrostatic 静电的electrostatic accelerator 静电加速器electrostatic attraction 静电引力electrostatic capacity 静电容量electrostatic deflection 静电偏转electrostatic energy 静电能electrostatic field 静电场electrostatic focusing 静电聚焦electrostatic force 静电力electrostatic generator 范德格拉夫发电机electrostatic induction 静电感应electrostatic ion microscope 静电离子显微镜electrostatic lens 静电透镜electrostatic oscillograph 静电示波器electrostatic potential 静电势electrostatic precipitation 静电吸尘electrostatic repulsion 静电斥力electrostatic septum 静电隔极electrostatic spectrometer 静电能谱仪electrostatic type 静电型electrostatic unit 静电单位electrostatic wave 静电波electrostatics 静电学electrostriction 电致伸缩electrostrictive vibrator 电致伸缩振动器electrothermal rocket 电热火箭electrothermic type 热电型electrovalence 电价electroweak interaction 弱电相互酌element 元素element semiconductor 元素半导体elementary cell 单位晶胞elementary charge 元电荷elementary colors 原色elementary excitation 元激发elementary function 基本机能elementary particle 基本粒子elementary particle physics 基本粒子物理学elementary particle reaction 基本粒子反应elementary process 基本过程elementary quantity 基本量elements of orbit 轨道要素ellipsoid for dielectric constants 介电常数椭球ellipsoid of inertia 惯量椭球ellipsoid of revolution 转动椭球ellipsoid of rotation 转动椭球ellipsoid of wave normals 光学指标ellipsoidal coordinates 椭球坐标ellipsometer 椭圆偏振计elliptic coordinates 椭圆坐标elliptic function 椭圆函数elliptic oscillation 椭圆振荡elliptic polarization 椭圆偏振elliptical galaxy 椭圆星云elliptical nebula 椭圆星云elliptically polarized light 椭圆偏振光elliptically polarized wave 椭圆偏振波elongation 伸长embrittlement 脆化emergency core cooling system 堆芯事故冷却系统emergency shut down 紧急停堆emission 发射emission band 发射带emission current 发射电流emission efficiency 发射效率emission line 发射谱线emission measure 发射量emission nebula 发射星云emission of light 光发射emission probability 发射概率emission spectroscopy 发射光谱学emission spectrum 发射谱emissivity 发射率emittance 发射率emitter 发射体;发射极emitter follower 发射极跟随器emmetropic eye 正常眼empirical formula 实验式empirical mass formula 经验质量公式empirical temperature 经验温度empirical temperature scale 经验温标empty band 空带empty level 空能级emulsion 乳胶emulsion chamber 乳胶室enamel 瓷漆enantiomorphism 对形性enantiotropes 互变性晶体enantiotropy 互变性encke's comet 端彗星encoder 编码器编码机encounter hypothesis 偶迂假说end 端end correction 端部校正end product 最终产物endlessness 无穷endosmosis 内渗endothermic reaction 吸热反应endurance limit 疲劳极限endurance test 疲劳试验energetics 能量学energy 能energy balance 能量平衡energy band 能带energy band structure 能带结构energy barrier 能量势垒energy carrier 能量载体energy conservation law 能量守恒律energy density 能量密度energy distribution 能量分布energy equivalent 能量当量energy exchange 能量交换energy flow 能量流能通量energy flow of electromagnetic field 电磁场的能量流energy flux 能通量energy flux vector 坡印廷矢量energy gap 能隙energy level 能级energy level diagram 能级图energy liberation 能量释放energy loss spectrum 能量损失谱energy momentum tensor 能量动量张量energy of absolute zero 绝对零点能energy of light 光能energy of thermal motion 热运动能量energy principle 能量原理energy quantum 能量量子energy release 能量释放energy source 能源energy source of star 星能源energy spectrum 能谱energy surface 能面energy transfer 能量传递energy transformation coefficient 能量变换系数energy unit 能单位energy yield 能量产额engine 发动机engineering acoustics 应用声学enriched reactor 浓缩燃料堆enriched uranium 浓缩铀enrichment 浓缩ensemble 系综ensemble average 系综平均entanglement 缠结enthalpy 焓entrance angle 入射角entrance pupil 入射光瞳entropy 熵entropy diagram 熵图entropy elasticity 熵弹性entropy flow 熵流entropy of activation 激活熵entropy of mixing 混合熵entropy production 熵产生entropy wave 熵波environmental radiation 环境辐射enzyme 酶ephemeris 历表ephemeris time 历书时epitaxial growth 外延生长epitaxial layer 外延层epitaxial planar transistor 外延平面晶体管epitaxial transistor 外延型晶体管epitaxy 外延epithermal energy 超热能epithermal neutron 超热中子epoch 历元epoxy resin 环氧尸epsilon expansion 展开equal temperament 平均乐律equation of continuity 连续性方程equation of light 光差equation of motion 运动方程equation of state 状态方程equation of time 时差equation of transfer 传递方程equatorial 赤道仪equatorial acceleration 赤道加速度equatorial coordinates 赤道坐标equatorial parallax 赤道视差equilibrium 平衡equilibrium constant 平衡常数equilibrium diagram 平衡图equilibrium process 平衡过程equilibrium state 平衡态equinox 分点equipartition 均分equipartition of energy 能量均分equiphase surface 等相面equipotential 等势的equipotential line 等位线equipotential surface 等势面equivalence of mass and energy 质能相当性equivalence principle 等价原理equivalent 当量equivalent circuit 等效电路equivalent electrons 等价电子equivalent mass 等效质量equivalent network 等效网络equivalent orbital 等效轨函数equivalent resistance 等效电阻equuleus 小马座erbium 铒erect image 正象erect lens 正象透镜erect system 正象系erecting eyepiece 正象目镜erg 尔格ergodic hypothesis 脯历经假说ergodic problem 脯历经问题ergodic property 脯历经性ergodic theorem 脯历经定理ergodic theory 脯历经理论eridanus 波江座ernst equation 厄伦斯特方程error 误差error equation 误差方程error function 误差函数error law 误差律error of measurement 测量误差eruptive prominence 爆发日珥es layer es 层esaki diode 江崎二极管estimate 估计estimation 估计etalon 标准具etch figures 蚀象etching 蚀刻ether 以太ettingshausen effect 厄廷好森效应euclidean field theory 欧几里得场论euclidean geometry 欧几里得几何euclidean space 欧几里得空间euler angle 欧拉角euler lagrange equation 欧拉拉格朗日方程europium 铕eutectic 共晶eutectic alloy 低共熔合金eutectic mixture 低共熔混合物eutectic point 低共熔点eutectoid 共析evacuation 抽空evaluation of crystal 晶体评价evaporated film 蒸镀薄膜evaporating black hole 蒸发黑洞evaporation 蒸发evection 出差even even nucleus 偶偶核even odd nucleus 偶奇核even parity 偶宇称性event 事件evolution 演化evolution of stars 恒星演化ewald construction 埃瓦得造图ewald method 埃瓦得法ewald sphere 埃瓦得球ex nova 燃后新星exa 艾exact 正确的exactitude 精确度example 例exceptional lie group 例外李群excess 过剩excess electron 过剩电子excess entropy production 过剩熵产生excess force 过剩力exchange 交换exchange charge 交换电荷exchange coefficient 交换系数exchange current 交换流exchange degeneracy 交换简并exchange energy 交换能量exchange force 交换力exchange integral 交换积分exchange interaction 交换相互酌exchange inversion 交换反演exchange narrowing 交换窄化exchange operator 交换算符exchange polarization 交换极化exchange potential 交换势exchange reaction 交换反应excimer 受激二聚物excimer laser 准分子激光器excitation 激发excitation cross section 激发截面excitation curve 激发曲线excitation energy 激发能excitation function 激发函数excitation level 受激能级excitation potential 激发电压excitation state 受激态excitation transfer 激发转移excited 激发的excited atom 受激原子excited level 受激能级exciter 励磁机exciting field 激磁场exciting force 激发力exciton 激子exciton condensation 激子凝聚exciton laser 激子激光器exciton phonon interaction 激子声子相互酌excitonic luminescence 激子发光excitonic molecule 激子分子excitonic phase 激子相exclusion principle 泡利不相容原理exclusive reaction 排斥反应exergy 放射本领exit pupil 出射光瞳exoelectron 外电子exothermic nuclear reaction 放热核反应exothermic reaction 放热反应exotic atom 异原子exotic baryon 外来重子exotic meson 外来介子exotic metal 异金属expanding universe 膨胀宇宙expansion 膨胀expansion coefficient 膨胀系数expansion of the universe 宇宙膨胀expansion ratio 膨胀率expectation 期待值expected value 期待值experiment 实验experimental design 试验设计experimental error 实验误差experimental facilities 实验装置experimental physics 实验物理学experimental radio astronomy 实验射电天文学experimental reactor 实验反应堆explosion 爆炸explosive 炸药explosive material 炸药explosive reaction 爆炸反应explosive shower 宇宙线爆发exposure 曝光exposure meter 曝光计expression 表示extended dislocation 扩展位错extensive air shower 广延空气簇射extensive variable 示量变量exterior derivative 外微商external conversion 外部转换external dose 外照射剂量external forces 外力external friction 外摩擦external memory 外部存储器external mirror laser 外镜式激光器external noise 外噪声external photoelectric effect 外部光电效应external pressure 环境压力external quenching 外部猝灭external storage 外部存储器extinction 消光extinction angle 消光角extinction coefficient 消光系数extinction distance 消光距离extinction effect 消光效应extinction fringe 消光条纹extinction method 消光法extinction voltage 淬火电压extitation potential 激发电位extra current 额外电流extra high vacuum 特高真空extragalactic nebula 河外星云extragalactic radio astronomy 河外射电天文学extraneous current 外来流extranuclear 核外的extranuclear electron 核外电子extranuclear structure 核外结构extraordinary rays 非常光线extraordinary wave 非常波extratropical cyclone 温带气旋extrinsic conduction 杂质导电extrinsic conductivity 非本斋导率extrinsic semiconductor 含杂质半导体extrinsic stacking fault 非本昭垛层错eye 眼eye glass 单片眼镜eye piece 接目透镜eyepiece micrometer 目镜测微计。
凝聚态物理现象理论与计算I 周森
Individual myosin fibrils composed of repeating units of mysoin interact with another repeating polymer, actin, to create organized contraction.
Atomic/molecular correlations
No intrinsic magnetism or other correlations
Intrinsic length scale = large effective Bohr radius a0 Weak correlation and large a0 enable simple and accurate modeling
Experimental evidence Large Fermi surface with Luttinger volume proportional to 1-x
(ARPES + Quantum Oscillations)
Cuprates: doped AF Mott insulator
Two-dimensional layered structure Most important physics in the common CuO2 plane Copper
3d electrons Oxygen
2p electrons
Cuprates are p-d charge transfer systems
“New clues”: unconventional SCs are often found in the vicinity of electronic ordered phases induced by interactions
微波促进碱性离子液体催化合成查尔酮
微波促进碱性离子液体催化合成查尔酮王壮坤【摘要】以4-氯-1-丁醇,N-甲基咪唑和苯甲酸钠为原料,用微波法制得碱性离子液体{[OHBMIM] PhCOO (ALL)},其结构经FT-IR表征;以苯甲醛和苯乙酮为原料,AIL 为催化剂,经微波促进的缩合反应合成了查尔酮(1),其结构经1 H NMR和FT-IR确证.考察了AIL用量、微波功率、物料比和反应时间对1产率的影响.合成1的最佳反应条件为:AIL1 mmol,苯甲醛5 mmol,n(苯甲醛)∶n(苯乙酮)=1.1,于微波功率140 W反应5 min,产率95.8％.AIL具有较好的循环使用性,循环使用6次,1产率没有明显降低.【期刊名称】《合成化学》【年(卷),期】2015(023)003【总页数】4页(P202-204,209)【关键词】碱性离子液体;微波促进;查尔酮;合成;工艺优化【作者】王壮坤【作者单位】辽宁石化职业技术学院石油化工系,辽宁锦州121001【正文语种】中文【中图分类】O621.3;O625.31查尔酮［1，3－二苯基丙烯酮(1)］广泛存在于甘草和红花等药用植物中，其分子结构由于具有较大柔性，能与很多受体结合，因而具有抗病毒、消炎、抗肿瘤和抗过敏等生物活性［1－3］。
1也是一种良好的非线性光学材料，可作为光存储、光计算机和激光波长转换材料［4］。
此外，1作为一种重要的有机合成中间体，可用于香料和药物等精细化学品的合成［5］。
1的传统合成方法是以苯乙酮及其衍生物为原料，在强酸或强碱催化下进行缩合反应。
该方法存在副反应多、产率低、产品分离困难、反应时间长和设备易被腐蚀等问题［6－7］。
近年来，用于该反应的有金属有机化合物［8］和金属化合物［9］等催化剂，但也存在催化剂制备困难、反应时间长和产率不高等缺点。
基于此，在文献报道微波辅助合成1的研究成果的基础上［10－12］，本文以4－氯－1－丁醇，N－甲基咪唑和苯甲酸钠为原料，用微波法制得碱性离子液体{［OHBMIM］PhCOO，AIL}，其结构经FT－IR 表征;以苯甲醛和苯乙酮为原料，AIL为催化剂，经微波促进的缩合反应合成了1(Scheme 1)，其结构经1H NMR和FT－IR确证。
Electron-phonon-coupling电子声子耦合
Total energy:
Atomic force:
Pulay corrections
Forces in DFT
Hellmann-Feynman force: classical electrostatic force excerted on the nucleus by the other nuclei and the electronic charge distribution
The Harmonic Approximation
N atoms per unit cell
# displacements Total energy
Forces
N=2
10
3
YBa2Cu3O7: N=13
703
19
5 Ag modes
21
4
Harmonic case only! Interpolation only – no fit!
Compuபைடு நூலகம்ational Effort
Many particle Schrödinger equation
electronic coordinates ionic coordinates groundstate wavefunction with respect to fixed ions
The Hellmann-Feynman Theorem
position point
Cu(1)
Ba
O(4)
[ a b c] symmetry
Y (½ ½ ½ ) Cu(1) ( 0 0 0 ) O(1) ( 0 ½ 0 )
Phonons & electron-phonon coupling