强磁场下石墨烯和拓扑绝缘体的晶格弛豫相关现象研究

项目名称： 强磁场下石墨烯和拓扑绝缘体的晶格弛豫相关现象研究

项目编号： No.11304355

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 数理科学和化学

项目作者： 王子武

作者单位： 天津大学

项目金额： 25万元

中文摘要： 近年来发现的新型低维材料石墨烯和拓扑绝缘体，由于其奇特的物理特性有望在未来光电子器件中有重大应用而迅速成为研究的热点。在强磁场作用下研究这些体系，是深刻认识其基本物性的一种重要方法。因此本课题拟针对这两种新型材料，在考虑载流子与多支频率声子作用的基础上，采用黄-里斯（Huang-Rhys）非辐射跃迁理论方法，深入研究强磁场下晶格弛豫效应对朗道能级间量子跃迁相关现象的影响。主要目标是通过对多声子弛豫和俄歇过程中晶格弛豫效应的研究，得出载流子非辐射跃迁机制的弛豫时间与磁场强度、载流子浓度、温度的依赖关系，为深入理解和有效控制非辐射过程奠定基础。同时，对辐射跃迁过程由于晶格弛豫效应所导致的展宽机制和温度依赖性也将重点研究，并对辐射和非辐射跃迁过程的相互竞争关系进行全面分析。在上述研究的基础上，结合玻尔兹曼输运理论，进一步研究晶格弛豫效应对载流子的霍尔迁移率、磁光导等基本输运物理量的影响。

中文关键词： 晶格弛豫；无辐射跃迁；石墨烯；拓扑绝缘体；多声子散射

英文摘要： In recent years, the appearing of novel low-dimensional materials graphene and topological insulator, because of its many peculiar properties are expected to have potential applications in new generation of optoelectronics and quickly become the hot spots in interdisciplinary research. The study of low-dimensional systems in presence of magnetic field not only can observe some novel physical phenomenon, but also is a very important way for understanding of the basic characteristics of materials. This project mainly intends to focus on the graphene and topological insulator system. In frames of Huang-Rhys's non-radiation transition model, we will study the quantum transitions related to the lattice relaxation under strong magnetic field by considering the charge carrier-phonon interaction. Our goal is that obtaining the relations of the relaxation time with the magnetic field, temperature and carrier density for the transitions between the Landau levels (LLs) in the multi-phonon transition and Auger processes and laying a foundation for the effective control of non-radiation recombination. We also discuss the mechanism of line-width and effects of temperature for the radiation transitions between LLs and give the comparisons between the relaxation time of radiation and non-radiation transitions in details. Based

英文关键词： lattice relaxation；non-radiation processes；graphene；topological insulator；multi-phonons scattering