硅烯中自旋和能谷旋量的输运调控

项目名称： 硅烯中自旋和能谷旋量的输运调控

项目编号： No.11464024

项目类型： 地区科学基金项目

立项/批准年度： 2015

项目学科： 数理科学和化学

项目作者： 汪宇

作者单位： 昆明理工大学

项目金额： 50万元

中文摘要： 硅烯是由单层硅原子按翘曲蜂窝结构排列的新型二维狄拉克电子材料，具有自旋和能谷旋量，深入研究硅烯中自旋和能谷极化输运的基础理论及其调控机制可进一步加深对硅烯奇异物性的理解，确立相关非传统逻辑器件结构及其构建的理论基础。本研究在综合分析既有研究重边缘态物理而对体态物理认识不足的基础上，结合硅烯所呈现的新奇物性，通过构建硅烯结、波导、量子环、量子点等多尺度、不同位型的量子结构，灵活运用紧束缚方法、非平衡格林函数方法和模型哈密顿量方法等研究手段，系统剖析结构中体态自旋(能谷)极化产生、输运和弛豫的內禀特性及其在尺度、位型、无序等內禀参量调控和电、磁、应力等外部激励下的响应规律，阐明硅烯中自旋和能谷极化输运调控的微观机制，总结符合相关逻辑器件构筑实际的自旋(能谷)极化输运调控的可行可靠策略，细致甄别体模输运与边缘模输运之间的差异，为发展硅烯基非传统自旋(能谷)电子器件确立系统化的科学依据。

中文关键词： 自旋电子学；电子输运；量子输运；低维纳米结构；介观系统

英文摘要： As a novel two-dimensional Dirac electronic material, silicene, a single sheet of silicon atoms arranged in a low-buckled honeycomb lattice, has not only a traditional spin degree of freedom but also a nontraditional one akin to spin, namely valley spinor. Thus, similar to spin in spintronics, studying the transport and manipulation of spin/valley degree of freedom in silicene would become strongly desirable to understand the exotic properties silicene has and establish the theoretical basis for the construction of novel spin/valley-based logic devices. In this project, following the systematic analysis on the reported activities in silicene community, we will mainly focus on the spin/valley-polarized transport as well as its manipulation in silicene nanosystems in its bulk regime, a shaded scheme when comparing to that in its edge state regime. Based on the peculiar properties of silicene, we will firstly construct various silicene nanostructures like silicene junction, waveguide, quantum ring, and dot, and then investigate the intrinsic characteristics on the generation, transport, and relaxation of spin/valley- polarized current in the constructed structure by flexibly applying tight-binding model, nonequilibrium Green function, or model Hamiltonian method. Subsequently, we will further investigate the possible effect of realistic parameters like size, configuration, and disorder on the acquired transport characteristics. Finally, we will further impose various external strategies like electric, magnetic, and strain field to modulate the spin/valley-polarized transport properties in silicene nanostructures. To sum up, we hope, combining the results achieved in the edge-mode transport, to understand systematically the microscopic principle on the transport and manipulation of spin/valley-polarized beams in silicene, search feasible yet reliable strategies on the manipulation of spin and valley degree of freedom to guide the realistic logic device construction, identify the difference and relation between bulk mode transport and edge mode transport, and establish the solid scientific knowledge for the development of novel spin and valley-based logic devices in atomically silicene systems.

英文关键词： Spintronics;Electronic transport;quantum transport;Low-dimensional nanostructure;mesoscopic system