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Topological insulator: a new quantized spin Hall resistance robust to dephasing
Hua Jiang1, Shuguang Cheng, Qing-feng Sun
1Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
Physical Review Letters
|August 8, 2009
Summary
Quantum spin Hall effect (QSHE) plateaus are robust against normal dephasing but sensitive to spin dephasing, surviving only in mesoscopic samples. A new spin Hall resistance is robust against all dephasing, reflecting QSHE
Area of Science:
- Condensed matter physics
- Topological materials
Background:
- The quantum spin Hall effect (QSHE) is a topological state of matter characterized by conducting edge states.
- Understanding the robustness of QSHE properties against environmental factors like dephasing is crucial for potential applications.
Purpose of the Study:
- To investigate the impact of normal and spin dephasing on the longitudinal resistance in QSHE systems.
- To define and analyze a new spin Hall resistance and its behavior under dephasing.
Main Methods:
- Theoretical analysis of dephasing effects on QSHE transport properties.
- Comparison of theoretical predictions with experimental results.
Main Results:
- Longitudinal resistance quantum plateaus in QSHE are robust against normal dephasing but fragile against spin dephasing, limiting their observation to mesoscopic samples.
- Longitudinal resistance scales linearly with sample length and is independent of sample width.
- A novel spin Hall resistance is introduced, exhibiting quantum plateaus robust to all dephasing mechanisms, observable in macroscopic samples.
Conclusions:
- Spin dephasing significantly degrades the longitudinal resistance quantum plateaus in QSHE.
- The proposed spin Hall resistance offers a more robust signature of the topological nature of QSHE, observable in larger systems.
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