项目名称: III族氮化物半导体异质结构中的自旋轨道耦合效应
项目编号: No.61306012
项目类型: 青年科学基金项目
立项/批准年度: 2014
项目学科: 无线电电子学、电信技术
项目作者: 李明
作者单位: 许昌学院
项目金额: 25万元
中文摘要: III族氮化物材料具有较长的自旋驰豫时间,且在其各种低维结构中存在强烈的自旋轨道耦合效应,为自旋电子学器件的实现提供了良好的基础。目前AlGaN/GaN异质结构中二维电子气中的自旋轨道耦合效应已经成为该领域的研究热点。本项目拟研究的主要内容包括:1)通过自恰求解薛定谔方程和泊松方程,计算AlGaN/GaN量子阱中的Rashba自旋劈裂随对称参数β和σ的变化关系。2)选择合适的基函数,把本征值方程投影到导带的子空间中,推导导带的Rashba自旋劈裂系数α关于面内波矢的表达式,将α按小量δ展开,得到非线性的Rashba自旋劈裂能,讨论影响AlGaN/GaN 异质结构中的非线性Rashba自旋劈裂的各种因素。3)把本征值方程投影到导带的子空间中,得到只含导带波函数的有效质量方程。考虑有两个束缚子带的AlGaN/GaN量子阱,得到自旋-轨道耦合系数的表达式,研究它随量子阱各参数的变化关系。
中文关键词: 自旋轨道耦合效应;二维电子气;Rashba 自旋劈裂;极化电场;自洽计算
英文摘要: For III nitride semiconductors, the long spin relaxation time and the strong spin-orbit coupling effect in its low dimensional structures provide a good basis for the realization of the spintronic devices. Now, the spin-orbit coupling effect in AlGaN/GaN heterostructures is a hot topic in this field. In this project, we mainly study the following problems: (1)By solving the Schr?dinger and Poisson equations self-consistently for AlGaN/GaN QWs, we calculate how the Rashba spin splitting changes as a function of symmetric parameters β and σ. (2)By choosing proper basis functions, the eight-band Kane Hamiltonian is projected into the 2×2 conduction-band space. Then we derive the Rashba spin splitting coefficient α for the conduction band relating the wave vector in the plane, and we expand α in powers of δ and obtain nonlinear Rashba spin splitting energy. Finally, we explore the factors deciding the nonlinear Rashba spin splitting energy in AlGaN/GaN heterostructures. (3) By projecting the characteristic equation into the subspace of the conduction band, we obtain the effective mass equation only containing the envelope functions of the conduction subbands. Then we obtain the expression for the spin-orbit coupling coefficient in AlGaN/GaN quantum well structure. Finally, we study how they change as a function of t
英文关键词: Spin-orbit coupling;2DEG;Rashba spin splitting;Polarized electric field;Self-consistent calculation