Topological Anderson insulator via disorder-recovered average symmetry

Abstract

We propose that the topological Anderson insulator (TAI) can be realized by introducing special disorder into a graphene with a modified Kane-Mele model. The disorder recovers symmetry under statistical averaging, which turns a trivial insulator into a topologically nontrivial insulator. When graphene is subjected to nonmagnetic adatoms in one sublattice or global uniform magnetic adatoms, the sublattice or time-reversal (TR) symmetry is broken, respectively, making the system topologically trivial. For the former one, randomly spatial distributed adatoms result in gapless edge states and quantized transport characteristics. Such randomization preserves the sublattice symmetry on average and the system becomes a TAI phase. For the latter one, the average TR symmetry is recovered by randomizing magnetization directions and the topological phase is protected. We demonstrate the existence of gapless edge states, but the differential conductance is no longer quantized. Moreover, we construct our proposal in electric circuits and observe the disorder-induced edge state through the circuit simulation. Our work provides a more simplified scheme to realize the TAI, and deepens the understanding of the relationship between the TAI and average symmetries.