Tunable Anderson metal-insulator transition in quantum spin-Hall insulators

Chui-Zhen Chen, Haiwen Liu, Hua Jiang, Qing-feng Sun, Ziqiang Wang, X. C. Xie
2015 Physical Review B  
We numerically study disorder effects in Bernevig-Hughes-Zhang (BHZ) model, and find that Anderson transition of quantum spin Hall insulator (QSHI) is determined by model parameters. The BHZ Hamiltonian is equivalent to two decoupled spin blocks which belong to the unitary class. In contrast to the common belief that 2D unitary system scales to insulator except at certain critical points, we find, through calculations scaling properties of the localization length, level statistics, and
more » ... stics, and participation ratio, that a possible exotic metallic phase emerges between QSHI and normal insulator phases in InAs/GaSb-type BHZ model. On the other hand, direct transition from QSHI to normal insulator is found in HgTe/CdTe-type BHZ model. Furthermore, we show that the metallic phase originates from the Berry phase and can survive both inside and outside the gap.
doi:10.1103/physrevb.91.214202 fatcat:zhmkcpe2gfeg7jhpdz2ub5i4ca