对称双势垒量子阱中自旋极化输运的时间特性

电子的隧穿时间是描述量子器件动态工作范围的重要指标. 本文考虑k³ Dresselhaus 自旋轨道耦合效应对系统哈密顿量的修正, 结合转移矩阵方法和龙格-库塔法来解含时薛定谔方程, 进而讨论了电子在非磁半导体对称双势垒结构中的透射系数及隧穿寿命等问题. 研究结果发现:由于k³ Dresselhaus 自旋轨道耦合效应使自旋简并消除, 并在时间域内得到了表达, 导致自旋向上和自旋向下电子的透射峰发生了自旋劈裂; 不同自旋取向的电子构建时间和隧穿寿命不同, 这是导致自旋极化的原因之一; 电子的自旋极化在时间上趋于稳定. 关键词： 自旋极化输运 透射系数 隧穿寿命 自旋极化率

Time of spin-polarized tunneling through a symmetric double-barrier quantum well structure

Tunneling time is an important factor to describe quantum electronic device. In this paper, the dynamic problem of spin-dependent tunneling is investigated by solving the time-dependent Schrödinger equation. The transmission coefficient and tunneling lifetime are discussed by use of mixing transfer-matrix and Runge-Kutta method. The k³ Dresselhaus term is considered to correct the effective Hamiltonian of the system in our calculation. The results show that the transmission peak of the electrons with different spin orientations split obviously. The building time and the tunneling lifetime through the double-barrier structure of Al_xGa_1-xSb material are different for the spin-down electron and spin-up electron. These time-dependent properties depend on the electronic spin orientation. It can be considered as one of reasons for spin polarization to appear. Additionally, the steady spin-polarization emerges in the well due to the k³ Dresselhaus spin-orbit coupling.
Keywords： spin-dependent transport transmission coefficient tunneling lifetime polarization efficiency