National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China.
Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China.
Sci Rep. 2016 May 5;6:25503. doi: 10.1038/srep25503.
We investigate the topological phase transitions in a two-dimensional time-reversal invariant topological superconductor in the presence of a Zeeman field. Based on the spin Chern number theory, we find that the system exhibits a number of topologically distinct phases with changing the out-of-plane component of the Zeeman field, including a quantum spin Hall-like phase, quantum anomalous Hall-like phases with total Chern number C = -2, -1, 1 and 2, and a topologically trivial superconductor phase. The BdG band gap closes at each boundary of the phase transitions. Furthermore, we demonstrate that the zero bias conductance provides clear transport signatures of the different topological phases, which are robust against symmetry-breaking perturbations.
我们研究了在存在塞曼场的情况下二维时间反演不变拓扑超导体中的拓扑相变。基于自旋陈数理论,我们发现随着外场的改变,系统表现出许多拓扑不同的相,包括量子自旋霍尔相、总陈数为 C=-2、-1、1 和 2 的量子反常霍尔相,以及拓扑平庸超导相。在相变的每个边界处,BdG 能隙都闭合了。此外,我们证明了零偏电导为不同拓扑相提供了清晰的输运特征,这些特征对对称破缺扰动具有鲁棒性。