基于CdTe/HgTe量子阱的二维拓扑绝缘体热电输运的理论研究

项目名称： 基于CdTe/HgTe量子阱的二维拓扑绝缘体热电输运的理论研究

项目编号： No.11304316

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： 李龙龙

作者单位： 中国科学院合肥物质科学研究院

项目金额： 25万元

中文摘要： 热电材料的性能取决于其热电优值。为了提高热电优值，材料最好同时是声子的绝缘体和电子的导体，但在常规材料中，这种要求往往是无法满足的，因为声子感受到的散射体同时也是电子的散射体。基于CdTe/HgTe量子阱的二维拓扑绝缘体是最近几年来发现的一种新的量子态物质，具有新奇的电子结构，其体态是有能隙的绝缘态而边缘态是无能隙的金属态。本项目中，我们拟利用这一材料体系来设计新型的热电材料，其理由在于边缘态的完美导通使得电导不受非磁杂质的散射而声导会受到极大的抑制，因此材料的热电优值预期将得到极大的提高。我们将采用基于八带Kane模型的约化哈密顿量方法和基于Boltzmann方程的热电输运理论来研究掺杂、温度和量子结构参数对CdTe/HgTe二维拓扑绝缘体的热电输运性质的影响。通过这些研究我们将揭示这类材料系统的热电输运性质的一般规律，为设计可能的新型热电器件提供相关的理论依据。

中文关键词： 拓扑绝缘体；边缘态(表面态)和体态；热电输运性质；；

英文摘要： The performance of thermoelectric materials depends on their figure of merit. To improve this value, the material system should be the insulator for phonons and the conductor for electrons simultaneously. However, such a requirement is always hard to be fulfilled in conventional materials because the scattering objects felt by phonons are also felt by electrons at the same time. Therefore, it's difficult to improve the figure of merit. In recent years, two-dimensional topological insulators based on CdTe/HgTe quantum wells are new states of quantum matter. They are characterized by the novel electronic structures with the gapped insulating bulk states and the gapless metallic edge states. In this proposal, we plan to employ such material system to design new thermoelectric materials. The reason relies on that the edge sates would be free from being scattered by non-magnetic impurities due to the perfectly conducting edge channels while the phonon conduction would be largely suppressed. As a result, it is anticipated that the figure of merit of such material will be greatly improved. We will use the reduced Hamiltonian method based on the eight-band Kane model and the thermoelectric transport theory derived from the Boltzmann equation to investigate the effects of doping, temperature and quantum structure paramet

英文关键词： Topological Insulators；Edge (Surface) States and Bulk States；Thermoelectric Transport Properties；；