Non-diagonal disorder enhanced topological properties of graphene with laser irradiation

TL;DR

This paper demonstrates that non-diagonal disorder in laser-irradiated graphene can induce and enhance topological properties, offering a new approach for experimental realization of topological phases.

Contribution

It reveals that non-diagonal disorder can induce topological phases in laser-irradiated graphene, expanding understanding beyond diagonal disorder effects.

Findings

Disorder induces nontrivial topological properties in graphene.

Laser irradiation can drive disordered graphene into topological phases non-adiabatically.

Topological properties characterized by Bott index and real-space Chern number.

Abstract

Laser irradiation, as a versatile tool to tune topological properties of electronic systems, is under intensive studies. Experimentally, laser irradiation induced anomalous Hall effect in graphene has been observed (McIver et al., Nat. Phys. 16, 38 (2020)). Disorder is ubiquitous in real materials, and it has been shown that diagonal disorders, i.e., onsite disorder, can enhance topological properties of time-periodically driven quantum materials (Titum et al., Phys. Rev. Lett. 114, 056801 (2015)). Here, we investigate circularly polarized laser irradiated graphene with non-diagonal disorders, i.e., disordered tunneling, and find that disorder can induce nontrivial topological properties, characterized by Bott index and the real-space Chern number. Moreover, we show that one can turn on the laser irradiation non-adiabatically to drive the disordered graphene into non-trivial topological phase. It is a scheme which is especially interesting for experimental implementations.