Département de Physique Théorique, Université de Genève, CH-1211 Genève, Switzerland.
Phys Rev Lett. 2012 Dec 14;109(24):246803. doi: 10.1103/PhysRevLett.109.246803. Epub 2012 Dec 11.
Localization of the helical edge states in quantum spin Hall insulators requires breaking time-reversal invariance. In experiments, this is naturally implemented by applying a weak magnetic field B. We propose a model based on scattering theory that describes the localization of helical edge states due to coupling to random magnetic fluxes. We find that the localization length is proportional to B^{-2} when B is small and saturates to a constant when B is sufficiently large. We estimate especially the localization length for the HgTe/CdTe quantum wells with known experimental parameters.
螺旋边缘态的局域化要求破坏时间反演不变性。在实验中，这可以通过施加弱磁场 B 自然地实现。我们提出了一个基于散射理论的模型，该模型描述了由于与随机磁通量耦合而导致的螺旋边缘态的局域化。我们发现，当 B 较小时，局域化长度与 B^{-2}成正比，当 B 足够大时，局域化长度饱和到一个常数。我们根据已知的实验参数估计了 HgTe/CdTe 量子阱的局域化长度。
