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arXiv 1601.02541cond-mat.mes-hall
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无时间约束对称系统中的拓扑Anderson绝缘子

Topological Anderson Insulators in Systems without Time-Reversal Symmetry

Ying Su, Y. Avishai, X. R. Wang

摘要:

HgTe量子阱中拓扑Anderson绝缘体(TAI)的出现表明,当保持时间反转对称性(TRS)时,由螺旋边态贡献的重入$2e^2/h$量子化电导所表征的拓扑相变是由无序驱动的.在这里,我们表明,当TRS被打破,TAI的物理变得更加丰富。与传统的拓扑绝缘体不同,在没有外部磁场的情况下,传统的拓扑绝缘体在量子反常霍尔效应区域中仅支持单个量子化的%电导,或者在TAI中仅支持单个重入量子化的%电导,我们的模型表现出新颖的TAI分布,显示出以非零陈数为特征的新颖的TAI相,表明出现了多个手性边缘模式。调整无序或费米能量(在拓扑平凡和非平凡相),驱动这些不同的TAI相之间的跃迁,其特征在于从$0$到$e^2/h$和从$e^2/h$到$2e^2/h$的量子化电导的跳跃。基于玻恩近似的有效介质理论在参数空间中给出了不同TAI相的精确描述。

英文摘要:

Occurrence of topological Anderson insulator (TAI) in HgTe quantum well suggests that when time-reversal symmetry (TRS) is maintained, the pertinent topological phase transition, marked by re-entrant $2e^2/h$ quantized conductance contributed by helical edge states, is driven by disorder. Here we show that when TRS is broken, the physics of TAI becomes even richer. The pattern of longitudinal conductance and nonequilibrium local current %Unlike for conventional topological insulators that, in the %absence of an external magnetic field, support only a single quantized %conductance in the quantum anomalous Hall effect region or a single %re-entrant quantized conductance in TAI, %our model exhibits novel TAI distribution displays novel TAI phases characterized by nonzero Chern numbers, indicating the occurrence of multiple chiral edge modes. Tuning either disorder or Fermi energy (in both topologically trivial and nontrivial phases), drives transitions between these distinct TAI phases, characterized by jumps of the quantized conductance from $0$ to $e^2/h$ and from $e^2/h$ to $2e^2/h$. An effective medium theory based on the Born approximation yields an accurate description of different TAI phases in parameter space.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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