Topological Anderson amorphous insulator

TL;DR

This paper introduces the topological Anderson amorphous insulator, showing how disorder can induce topological phases in amorphous materials, characterized by robust edge states and quantized conductance.

Contribution

It demonstrates that Anderson disorder can drive amorphous systems into topological insulators, revealing a disorder-induced topological phase transition in noncrystalline materials.

Findings

Disorder induces topological phase transition in amorphous systems.

Robust edge states and quantized conductance observed.

Phase diagrams illustrate the disorder-driven topological transition.

Abstract

The topological phase in amorphous systems adds a new dimension to the topological states of matter. Here, we present an interesting phenomenon dubbed the topological Anderson amorphous insulator (TAAI). Anderson disorder can drive topologically trivial amorphous systems with structural disorders into noncrystalline topological insulators. The gap closing and reopening, spin Bott index, robust edge states, and quantized conductance characterize the Anderson disorder-induced nontrivial topology in amorphous systems. More importantly, phase diagrams are given for the topological phase transition (TPT). It is found that amorphous structural disorder and Anderson disorder are synergistic to drive the s-p band inversion of the system and hence the TPT, which is further confirmed by the effective medium theory. Our findings report a disorder-induced topological phenomenon in noncrystalline systems and shed light on the physical understanding of the interplay between the coexistence of two types of disorder effects and topology.