Spin relaxation in a zinc-blende (110) symmetric quantum well with δ doping
Spin relaxation in a zinc-blende (110) symmetric quantum well with δ doping
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δ 掺杂闪锌矿 (110) 对称量子阱中的自旋弛豫
DOI：
10.1103/physrevb.89.075314
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
and Y. Egami
中科院分区：
文献类型：
--
作者：
H. Akera;H. Suzuura;and Y. Egami
本文从理论上研究了当量子阱平行于锌-锗结构的（110）面，自旋极化垂直于阱，电子只占据基态子带时，在对称量子阱中形成的二维电子系统（2DES）的自旋弛豫.自旋弛豫速率被计算为放置在阱层中的施主杂质的分布的函数。考虑的自旋弛豫过程是（1）由杂质势诱导的自旋轨道相互作用（SOI）引起的子带内过程，这是2DES中的Elliott-Yafet机制，以及（2）由（2a）阱势诱导的SOI或（2b）Dresselhaus SOI引起的自旋翻转和来自杂质的散射组成的虚拟子带间过程。结果表明，当所有杂质都位于阱的中心平面上时，上述过程均消失。即使杂质分布在三个（110）原子层上，自旋弛豫速率也比均匀分布在7.5nm阱宽上的自旋弛豫速率低两个数量级。在GaAs/AlGaAs Ⅰ型量子威尔斯阱中，过程（1）和（2a）相长干涉，在阱宽为10 nm时比过程（2b）占优势，而在某些Ⅱ型量子威尔斯阱中，过程（1）和（2a）相消干涉。
The spin relaxation of a two-dimensional electron system (2DES) formed in a symmetric quantum well is studied theoretically when the quantum well is parallel to the (110) plane of the zinc-blende structure, the spin polarization is perpendicular to the well, and electrons occupy only the ground subband. The spin-relaxation rate is calculated as a function of the distribution of donor impurities which are placed in the well layer. Considered processes of the spin relaxation are (1) the intrasubband process by impurity-potential-induced spin-orbit interaction (SOI), which is the Elliott-Yafet mechanism in the 2DES, and (2) virtual intersubband processes consisting of a spin flip by (2a) well-potential-induced SOI or (2b) the Dresselhaus SOI, and a scattering from an impurity. It is shown that all of the above processes disappear when all impurities are located on the center plane of the well. Even if impurities are distributed over three (110) atomic layers, the spin-relaxation rate is two orders of magnitude lower than that for the uniform distribution over the well width of 7.5 nm. In GaAs/AlGaAs type-I quantum wells, the processes (1) and (2a) interfere constructively, being dominant over (2b) for the well width of10 nm, while in some type-II quantum wells, they can interfere destructively.