中国物理B ›› 2012, Vol. 21 ›› Issue (11): 117301-117301.doi: 10.1088/1674-1056/21/11/117301

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The robustness of quantum spin Hall effect to the thickness fluctuation in HgTe quantum wells

郭怀明a, 张相林b, 冯世平b   

  1. a Department of Physics, Beihang University, Beijing 100191, China;
    b Department of Physics, Beijing Normal University, Beijing 100875, China
  • 收稿日期:2012-06-01 修回日期:2012-07-26 出版日期:2012-10-01 发布日期:2012-10-01
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 11104189 and 11074023) and the National Basic Research Program of China (Grant Nos. 2011CBA00102, 2011CB921700, and 2012CB821403).

The robustness of quantum spin Hall effect to the thickness fluctuation in HgTe quantum wells

Guo Huai-Ming (郭怀明)a, Zhang Xiang-Lin (张相林)b, Feng Shi-Ping (冯世平 )b   

  1. a Department of Physics, Beihang University, Beijing 100191, China;
    b Department of Physics, Beijing Normal University, Beijing 100875, China
  • Received:2012-06-01 Revised:2012-07-26 Online:2012-10-01 Published:2012-10-01
  • Contact: Guo Huai-Ming E-mail:hmguo@buaa.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 11104189 and 11074023) and the National Basic Research Program of China (Grant Nos. 2011CBA00102, 2011CB921700, and 2012CB821403).

摘要: The quantum spin Hall effect (QSHE) was first realized in HgTe quantum wells (QWs), which remain the only known two-dimensional topological insulator so far. In this paper, we have systematically studied the effect of the thickness fluctuation of HgTe QWs on the QSHE. We start with the case of constant mass with random distributions, and reveal that the disordered system can be well described by a virtual uniform QW with an effective mass when the number of components is small. When the number is infinite and corresponds to the real fluctuation, we find that the QSHE is not only robust, but also can be generated by relatively strong fluctuation. Our results imply that the thickness fluctuation does not cause backscattering, and the QSHE is robust to it.

关键词: quantum spin Hall effect, HgTe quantum wells, disorder effect

Abstract: The quantum spin Hall effect (QSHE) was first realized in HgTe quantum wells (QWs), which remain the only known two-dimensional topological insulator so far. In this paper, we have systematically studied the effect of the thickness fluctuation of HgTe QWs on the QSHE. We start with the case of constant mass with random distributions, and reveal that the disordered system can be well described by a virtual uniform QW with an effective mass when the number of components is small. When the number is infinite and corresponds to the real fluctuation, we find that the QSHE is not only robust, but also can be generated by relatively strong fluctuation. Our results imply that the thickness fluctuation does not cause backscattering, and the QSHE is robust to it.

Key words: quantum spin Hall effect, HgTe quantum wells, disorder effect

中图分类号:  (Weak or Anderson localization)

  • 73.20.Fz
72.80.Sk (Insulators) 72.15.Rn (Localization effects (Anderson or weak localization))