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arXiv 1602.01360cond-mat.str-el
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带折射率依赖的输运弛豫时间在反常霍尔效应中的作用

The role of band-index-dependent transport relaxation times in anomalous Hall effect

Cong Xiao, Dingping Li, Zhongshui Ma

摘要:

我们重新回顾了反常霍尔效应(AHE)的模型计算,并表明,在具有点状势杂质的各向同性Rashba耦合二维电子气(2DEG)中,半经典Boltzmann方程(SBE)的完全解可能不同于广泛使用的$1/τ^{||}$和$1/τ^{\perp}$解[Phys. Rev. B 68,165311(2003)]。我们对AHE的方法类似于各向异性磁阻的基于SBE的分析,导致分布函数的积分方程[Phys.Rev.B79,045427(2009)],但在本例中,我们将描述简化为带折射率相关的输运弛豫时间。当两个Rashba带都被部分占据时,这些通过求解线性方程组来确定。详细的计算表明,对于本征散射和混合斜散射,当费米能级较大时,$1/τ^{||}$和$1/τ^{\perp}$与SBE完全解的差别是显著的。对于坐标偏移效应,在带间弹性散射过程中获得的侧跳速度被证明是更重要的较大的Rashba耦合,甚至可能超过带内的外部Rashba带。在所考虑的情况下,坐标位移对AHE的贡献显着不同于之前分析的光滑无序势的限制。

英文摘要:

We revisit model calculations of the anomalous Hall effect (AHE) and show that, in isotropic Rashba-coupled two-dimensional electron gas (2DEG) with pointlike potential impurities, the full solution of the semiclassical Boltzmann equation (SBE) may differ from the widely-used $1/τ^{||}$ & $1/τ^{\perp}$ solution [Phys. Rev. B 68, 165311 (2003)]. Our approach to AHE is analogous to the SBE-based analysis of the anisotropic magnetoresistance leading to an integral equation for the distribution function [Phys. Rev. B 79, 045427 (2009)] but in the present case, we reduce the description to band-index-dependent transport relaxation times. When both Rashba bands are partially occupied, these are determined by solving a system of linear equations. Detailed calculations show that, for intrinsic and hybrid skew scatterings the difference between $1/τ^{||}$ & $1/τ^{\perp}$ and the full solution of SBE is notable for large Fermi energies. For coordinate-shift effects, the side-jump velocity acquired in the inter-band elastic scattering process is shown to be more important for larger Rashba coupling and may even exceed the intra-band one for the outer Rashba band. The coordinate-shift contribution to AHE in the considered case notably differs from that in the limit of smooth disorder potential analyzed before.

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