Connecting Topological Anderson and Mott Insulators in Disordered Interacting Fermionic Systems

TL;DR

This paper demonstrates that topological Anderson and Mott insulators can be connected in a disordered, interacting fermionic system, revealing a new disordered correlated topological insulator phase and providing a unified understanding of topological phase transitions.

Contribution

It introduces a model linking topological Anderson and Mott insulators in interacting fermions, uncovering a new disordered correlated topological phase and applying machine learning for phase identification.

Findings

Topological Anderson and Mott insulators are adiabatically connected without gap closing.

A disordered correlated topological insulator phase is identified.

Machine learning confirms the phase diagram and topological properties.

Abstract

The topological Anderson and Mott insulators are two phases that have so far been separately and widely explored beyond topological band insulators. Here we combine the two seemingly different topological phases into a system of spin-1/2 interacting fermionic atoms in a disordered optical lattice. We find that the topological Anderson and Mott insulators in the noninteracting and clean limits can be adiabatically connected without gap closing in the phase diagram of our model. Lying between the two phases, we uncover a disordered correlated topological insulator, which is induced from a trivial band insulator by the combination of disorder and interaction, as the generalization of topological Anderson insulators to the many-body interacting regime. The phase diagram is determined by computing various topological properties and confirmed by unsupervised and automated machine learning. We develop an approach to provide a unified and clear description of topological phase transitions driven by interaction and disorder. The topological phases can be detected from disorder/interaction induced edge excitations and charge pumping in optical lattices.