中国物理B ›› 2012, Vol. 21 ›› Issue (7): 77303-077303.doi: 10.1088/1674-1056/21/7/077303

• CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES • 上一篇    下一篇

Quantum spin Hall effect in a square-lattice model under a uniform magnetic field

郭怀明a, 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:2012-01-03 修回日期:2012-02-07 出版日期:2012-06-01 发布日期:2012-06-01
  • 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).

Quantum spin Hall effect in a square-lattice model under a uniform magnetic field

Guo Huai-Ming(郭怀明)a)† and 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:2012-01-03 Revised:2012-02-07 Online:2012-06-01 Published:2012-06-01
  • 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).

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摘要： We study a toy square-lattice model under a uniform magnetic field. Using the Landauer--B黷tiker formula, we calculate the transport properties of the system on a two-terminal, a four-terminal, and a six-terminal device. We find that the quantum spin Hall (QSH) effect appears in energy ranges where the spin-up and spin-down subsystems have different filling factors. We also study the robustness of the resulting QSH effect and find that it is robust when the Fermi levels of both spin subsystems are far away from the energy plateaus but is fragile when the Fermi level of any spin subsystem is near the energy plateaus. These results provide an example of QSH effect with the physical origin other than time-reversal (TR) preserving spin-orbit coupling (SOC).

关键词: quantum spin Hall effect, topological insulator

Abstract: We study a toy square-lattice model under a uniform magnetic field. Using the Landauer--B黷tiker formula, we calculate the transport properties of the system on a two-terminal, a four-terminal, and a six-terminal device. We find that the quantum spin Hall (QSH) effect appears in energy ranges where the spin-up and spin-down subsystems have different filling factors. We also study the robustness of the resulting QSH effect and find that it is robust when the Fermi levels of both spin subsystems are far away from the energy plateaus but is fragile when the Fermi level of any spin subsystem is near the energy plateaus. These results provide an example of QSH effect with the physical origin other than time-reversal (TR) preserving spin-orbit coupling (SOC).

Key words: quantum spin Hall effect, topological insulator

中图分类号:  (Quantum Hall effects)

  • 73.43.-f
72.25.Hg (Electrical injection of spin polarized carriers) 73.20.-r (Electron states at surfaces and interfaces) 85.75.-d (Magnetoelectronics; spintronics: devices exploiting spin polarized transport or integrated magnetic fields)