Statistical model for the effects of phase and momentum randomization on electron transport
Statistical model for the effects of phase and momentum randomization on electron transport
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DOI：
10.1140/epjb/e2012-30348-y
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发表时间：
2012-06
期刊：
影响因子：
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通讯作者：
T. Stegmann;M. Zilly;O. Ujsághy;D. Wolf
中科院分区：
文献类型：
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作者：
T. Stegmann;M. Zilly;O. Ujsághy;D. Wolf
介绍了一维量子系统中退相对电子输运影响的一个简单的统计模型，该模型允许独立地调节位相和动量的随机化程度。因此，该模型能够描述介于经典输运和量子输运之间的中间区域的输运。该模型是基于Büttiker的方法，使用虚拟水库来实现退相效果。然而，与其他模型不同的是，在虚拟储集层假设完全的相位随机化，这有效地将系统划分为更小的相干子系统，并计算随机分布的去相储集层的集合平均。这种方法不仅减少了计算时间，而且还允许对系统属性进行新的了解。这样，在推导出紧束缚链无序平均电阻的有效公式后，结果表明，退相驱动的从局域指数行为到欧姆-线性行为的转变不受动量随机化退相程度的影响。
A simple statistical model for the effects of dephasing on electron transport in one-dimensional quantum systems is introduced, which allows to adjust the degree of phase and momentum randomization independently. Hence, the model is able to describe the transport in an intermediate regime between classical and quantum transport. The model is based on Büttiker’s approach using fictitious reservoirs for the dephasing effects. However, in contrast to other models, at the fictitious reservoirs complete phase randomization is assumed, which effectively divides the system into smaller coherent subsystems, and an ensemble average over randomly distributed dephasing reservoirs is calculated. This approach reduces not only the computation time but allows also to gain new insight into system properties. In this way, after deriving an efficient formula for the disorder-averaged resistance of a tight-binding chain, it is shown that the dephasing-driven transition from localized-exponential to ohmic-linear behavior is not affected by the degree of momentum randomizing dephasing.