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Optical vibration modes and electron-phonon interaction in ternary mixed crystals of polar semiconductors

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Chinese Physics B 2004年第1期13卷 71-81页

作者：梁希侠班士良 DepartmentofPhysics InnerMongoliaUniversityHohhot010021China

Optical vibrations of the lattice and the electron-phonon interaction in polar ternary mixed crystals are studied in the framework of the continuum model of Born and Huang and the random-element-isodisplacement model. A normal-coordinate system to describe the optical vibration in ternary mixed crystals is correctly adopted to derive a new Frohlich-like Hamiltonian for the electron-phonon interaction including the unit-cell volume variation *** numerical results for the phonon modes, the electron-phonon coupling constants and the polaronic energies for several typical materials are obtained. It is verified that the nonlinearity of the electron-phonon coupling effects with the composition is essential and the unit-cell volume effects cannot be neglected for most ternary mixed crystals.

关键词： optical vibration mode electron-phonon interaction ternary mixed crystal

PERSISTENT CURRENT IN A ONE-DIMENSIONAL MESOSCOPIC RING WITH electron-phonon interaction IN THE LATTICE MODEL

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Journal of Shanghai Jiaotong university(Science) 2001年第2期6卷 123-125,130页

作者：李铜忠 Dept. of Physics Shanghai Jiaotong Univ.

A new non-perturbative method is used to discuss the persistent current in a one-dimensional mesoscopic ring threaded by a flux φ with electron-phonon interaction in the lattice model. The current is periodic in φ with a flux quantum φ 0 and the electron-phonon interaction suppresses the persistent current. By considering the contributions of many-phonon correlations, we could obtain more accurate results.

关键词： mesoscopic ring electron-phonon interaction lattice model persistent current

Versatile band structure and electron-phonon coupling in layered PtSe_(2) with strong interlayer interaction

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Nano Research 2022年第7期15卷 6613-6619页

作者： Junbo He Xudan Zhu Weiming Liu Ertao Hu Jianlu Wang Rongjun Zhang Department of Optical Science and Engineering Fudan UniversityShanghai 200433China College of electronic and Optical Engineering Nanjing University of Posts and TelecommunicationsNanjing 210023China Institute of Optoelectronics Fudan UniversityShanghai 200433China Academy for Engineering and Technology Fudan UniversityShanghai 200433China Yiwu Research Institute of Fudan University Yiwu 322000China

The large tunability in the band structure is ubiquitous in two-dimensional(2D)materials,and PtSe_(2) is not an exception,which has attracted considerable attention in electronic and optoelectronic applications due to its high carrier mobility and long-term *** dimensional dependent properties are closely related to the evolution of electronic band *** points(CPs),the extrema or saddle points of electronic bands,are the cornerstone of condensed-matter physics and fundamentally determine the optical and transport phenomena of the layered PtSe_(2).Here,we have experimentally revealed the detailed electronic structures in layered PtSe_(2),including the CPs in the Brillouin zones(BZs),by means of reflection contrast spectroscopy and spectroscopic ellipsometry(SE).There are three critical points in the BZs attributed to the excitonic transition,quasi-particle band gap,and the band nesting effect related transition,*** CPs show red-shifting trends with increasing layer number under the mechanism of strong interlayer *** have further revealed the electron–phonon(e–ph)interaction in such layered material,utilizing temperature-dependent absorbance *** strength of e–ph interaction and the average phonon energy also decline with the increasement of layer *** findings give a deep understanding to the physics of the layer-dependent evolution of the electronic structure of PtSe_(2),potentially leading to applications in optoelectronics and electronic devices.

关键词： layered transition metal dichalcogenides PtSe_(2)thin films interlayer coupling critical points electron-phonon interaction

Anisotropic polarization due to electron-phonon interactions in graphene

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Journal of Semiconductors 2009年第11期30卷 6-9页

作者：李武群曹俊诚 State Key Laboratory of Functional Materials for Informatics Shanghai Institute of Microsystem and Information TechnologyChinese Academy of Sciences

Polarization plays an important role in the Raman spectroscopy. We study, in graphene, anisotropic polarization due to electron-phonon coupling （EPC）. The numerical results show that the anisotropy is obvious even when the wave vector is in the range of the Raman experiment. The analytical expression is deduced from the structure factor, which indicates the crucial origin of the anisotropy. We also find that, as the phonon energy increases the polarization is clearly weakened due to the screen effect of EPC, but the anisotropy totally remains.

关键词： graphene electron-phonon interaction anisotropy polarization

Effects of electron-and impurity-ion-LO phonon couples on the impurity states in cylindrical quantum wires

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Journal of Semiconductors 2009年第6期30卷 15-19页

作者：赵增茹梁希侠 Department of Physics Inner Mongolia University

The variational method and the effective mass approximation are used to calculate the phonon effects on the hydrogenic impurity states in a cylindrical quantum wire with finite deep potential by taking both the couplings of the electron-confined bulk longitudinal optical（LO） phonons and the impurity-ion-LO phonons into *** binding energies and the phonon contributions are calculated as functions of the transverse dimension of the quantum *** results show that the polaronic effect induced by the electron-LO phonon coupling and the screening effect induced by the impurity-ion-LO phonon coupling tend to compensate each other and the total effects reduce the impurity binding energies.

关键词： quantum wire electron-phonon interaction impurity states

phonon-dependent transport through a serially coupled double quantum dot system

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Chinese Physics B 2014年第5期23卷 510-515页

作者： M.Bagheri Tagani H.Rahimpour Soleimani Department of Physics University of Guilan

Using Keldysh nonequilibrium Green function formalism and mapping a many-body electron-phonon interaction onto a one body problem, the electron transport through a serially coupled double quantum dot system is analyzed. The influence of the electron-phonon interaction, temperature, detuning, and interdot tunneling on the transmission coefficient and current is studied. Our results show that the electron-phonon interaction results in the appearance of the side peaks in the transmission coefficient, whose height is strongly dependent on the phonon temperature. We have also found that the inequality of the electron-phonon interaction strength in two dots gives rise to an asymmetry in the current-voltage characteristic. In addition, the temperature difference between the phonon and electron subsystems results in the reduction of the saturated current and the destruction of the step-like behavior of the current. It is also observed that the detuning can improve the magnitude of the current by compensating the mismatch of the quantum dots energy levels induced by the electron-phonon interaction.

关键词： quantum dot electron-phonon interaction Keldysh nonequilibrium Green function formalism,current-voltage characteristic

Low-Temperature Thermal Conductance in Superlattice Nanowire with Structural Defect

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Chinese Physics Letters 2008年第6期25卷 2107-2110页

作者：王新军刘景锋李水 Institute of Mathematics and Physics Central South University of Forestry and Technology Changsha 420004 College of Science South China Agricultural University Guangzhou 520642

Using the scattering-matrix cascading method, we investigate the effect of structural defect on the acoustic phonon transmission and thermal conductance in the superlattice nanowire at low temperatures. In the present system, the phonon transmissions exhibit quite complex oscillatory behaviour. It is found that a lateral defect in an otherwise periodic structure significantly decrease the thermal conductance and completely washes away the transmission quantization. However, the appreciable transmission quantization survives in the presence of a longitudinal defect whereas a good quantization plateau of thermal conductance emerges below the universal level in a wide temperature range with the lateral defect.

关键词： electron-phonon interaction QUANTUM MODES CONDUCTIVITY TRANSITION TRANSPORT

Quantum dynamics of electric-dipole coupled defect centers in solids

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Communications in Theoretical Physics 2021年第1期73卷 54-61页

作者： Feng Tang Lei-Ming Zhou Nan Zhao Beijing Computational Science Research Center Beijing 100193China

We investigate the quantum dynamics of two defect centers in solids,which are coupled by vacuum-induced dipole-dipole *** the interaction between defects and phonons is taken into account,the two coupled electron-phonon systems make up two equivalent multilevel *** making Born-Markov and rotating wave approximations,we derive a master equation describing the dynamics of the coupled multilevel *** results indicate the concepts of subradiant and superradiant states can be applied to these systems and the population transfer process presents different behaviors from those of the two dipolar-coupled two-level atoms due to the participation of phonons.

关键词： dipole-dipole interaction electron-phonon interaction superradiance

Group velocity matters for accurate prediction of phonon-limited carrier mobility

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Chinese Physics B 2021年第8期30卷 449-455页

作者：杨巧林邓惠雄魏苏淮骆军委 State Key Laboratory of Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Beijing Computational Science Research Center Beijing 100193China Beijing Academy of Quantum Information Sciences Beijing 100193China

First-principles approaches have recently been developed to replace the phenomenological modeling approaches with adjustable parameters for calculating carrier mobilities in ***,in addition to the high computational cost,it is still a challenge to obtain accurate mobility for carriers with a complex band structure,e.g.,hole mobility in common ***,we present a computationally efficient approach using isotropic and parabolic bands to approximate the anisotropy valence bands for evaluating group velocities in the first-principles *** treatment greatly reduces the computational cost in two ways:relieves the requirement of an extremely denseκmesh to obtain a smooth change in group velocity,and reduces the 5-dimensional integral to 3-dimensional *** Si and SiC as two examples,we find that this simplified approach reproduces the full first-principles calculation for *** we use experimental effective masses to evaluate the group velocity,we can obtain hole mobility in excellent agreement with experimental data over a wide temperature *** findings shed light on how to improve the first-principles calculations towards predictive carrier mobility in high accuracy.

关键词： electron-phonon interaction phonon-limited hole mobility Boltzmann transport equation