Anderson disorder-induced nontrivial topological phase transitions in two-dimensional topological superconductors

Abstract

We numerically investigate the quantum phase transitions induced by Anderson disorder in a topological superconductor (TSC), which is composed of a quantum anomalous Hall insulator (QAHI) and a proximity coupled $s$-wave superconductor (SC). From the transport phenomena presented, we deduce that with the increase of Anderson disorder strength, the topological quantum phase changes from Chern number $\mathcal{N}=0$ to $\mathcal{N}=1$ and finally to $\mathcal{N}=2$. Then we use the effective-medium theory to verify our numerical results and conclude that the phase transitions should ascribe to the negative correction of topological mass.