Photonic topological Anderson insulator in a two-dimensional atomic lattice

TL;DR

This paper demonstrates that disorder in a 2D atomic honeycomb lattice can induce a topological Anderson insulator phase characterized by edge states and localized bulk modes, with a transition to a topological insulator phase.

Contribution

It reveals the emergence of a topological Anderson insulator in a 2D atomic lattice, highlighting the role of disorder and symmetry breaking in topological phase transitions.

Findings

Disorder induces a topological Anderson insulator phase.

TAI exhibits nonzero topological invariant and edge states.

Transition from TAI to TI occurs at constant topological invariant.

Abstract

Disorder in atomic positions can induce a topologically nontrivial phase - topological Anderson insulator (TAI) - for transverse electric optical quasimodes of a two-dimensional honeycomb lattice of immobile atoms. TAI requires both time-reversal and inversion symmetries to be broken to similar extents. It is characterized by a nonzero topological invariant, a reduced density of states and spatially localized quasimodes in the bulk, as well as propagating edge states. A transition from TAI to the topological insulator (TI) phase can take place at a constant value of the topological invariant, showing that TAI and TI represent the same topological phase.