Spin relaxation due to the Bir-Aronov-Pikus mechanism in intrinsic and p -type GaAs quantum wells from a fully microscopic approach
Spin relaxation due to the Bir-Aronov-Pikus mechanism in intrinsic and p -type GaAs quantum wells from a fully microscopic approach
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DOI：
10.1103/physrevb.77.075318
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发表时间：
2007-05
影响因子：
3.7
通讯作者：
J. Zhou;M. W. Wu
中科院分区：
文献类型：
--
作者：
J. Zhou;M. W. Wu
通过构造和数值求解动力学自旋Bloch方程，研究了本征和p$型（001）GaAs量子阱威尔斯中的电子自旋弛豫。所有相关的散射都明确包括在内，特别是自旋翻转电子-重空穴交换散射，导致Bir-Aronov-Pikus自旋弛豫。我们表明，由于费米黄金法则方法忽略了电子-重空穴交换散射中的非线性项，Bir-Aronov-Pikus机制引起的自旋弛豫在中等高电子密度和低温下被大大夸大了文献中。我们比较了由于Bir-Aronov-Pikus机制和由于D 'yakonov-Perel'机制的自旋弛豫时间，D 'yakonov-Perel'机制也是从动力学自旋Bloch方程计算的，包括所有的散射，特别是自旋守恒的电子-电子和电子-重空穴散射。我们发现，在本征量子威尔斯阱中，低温时Bir-Aronov-Pikus机制的效应比D 'yakonov-Perel'机制的效应小得多，高温时小不到一个数量级.在p$型量子威尔斯中，当量子阱的空穴密度和宽度足够大时，由于Bir-Aronov-Pikus机制引起的自旋弛豫在低温下也比由于D 'yakonov-Perel'机制引起的自旋弛豫小得多，并且在较高温度下变得相当.我们认为，与体样品不同，Bir-Aronov-Pikus机制在二维样品中几乎不占主导地位。
We study the electron spin relaxation in intrinsic and $p$-type (001) GaAs quantum wells by constructing and numerically solving the kinetic spin Bloch equations. All the relevant scatterings are explicitly included, especially the spin-flip electron-heavy hole exchange scattering which leads to the Bir-Aronov-Pikus spin relaxation. We show that, due to the neglection of the nonlinear terms in the electron-heavy hole exchange scattering in the Fermi-golden-rule approach, the spin relaxation due to the Bir-Aronov-Pikus mechanism is greatly exaggerated at moderately high electron density and low temperature in the literature. We compare the spin relaxation time due to the Bir-Aronov-Pikus mechanism with that due to the D'yakonov-Perel' mechanism which is also calculated from the kinetic spin Bloch equations with all the scatterings, especially the spin-conserving electron-electron and electron-heavy hole scatterings, included. We find that, in intrinsic quantum wells, the effect from the Bir-Aronov-Pikus mechanism is much smaller than that from the D'yakonov-Perel' mechanism at low temperature, and it is smaller by no more than one order of magnitude at high temperature. In $p$-type quantum wells, the spin relaxation due to the Bir-Aronov-Pikus mechanism is also much smaller than the one due to the D'yakonov-Perel' mechanism at low temperature and becomes comparable to each other at higher temperature when the hole density and the width of the quantum well are large enough. We claim that unlike in the bulk samples, the Bir-Aronov-Pikus mechanism hardly dominates the spin relaxation in two-dimensional samples.