Topological Mott transition in a Weyl-Hubbard model with dynamical mean-field theory

TL;DR

This paper explores how strong interactions in a Weyl-Hubbard model can induce a topological Mott transition, using dynamical mean-field theory to analyze changes in topological invariants and quasiparticle properties.

Contribution

It introduces a detailed DMFT-based analysis of the topological phase transition from Weyl semimetal to Mott insulator, focusing on topological invariants and quasiparticle band topology.

Findings

Chern numbers become trivial in the Mott insulating phase

Interaction effects can drive a topological phase transition

Analysis of quasiparticle and blind bands enhances understanding

Abstract

Weyl semimetals are three-dimensional, topologically protected, gapless phases which show exotic phenomena such as Fermi arc surface states or negative magnetoresistance. It is an open question whether interparticle interactions can turn the topological semimetal into a topologically nontrivial Mott insulating phase. We investigate an experimentally motivated model for Weyl physics of cold atoms in optical lattices, with the main focus on interaction effects and topological properties by means of dynamical mean-field theory (DMFT). We characterize topological phases by numerically evaluating the Chern number via the Ishsikawa-Matsuyama formula for interacting phases. Within our studies, we find that the Chern numbers become trivial when interactions lead to insulating behavior. For a deeper understanding of the Weyl-semimetal-to-Mott-insulator topological phase transition, we evaluate the topological properties of quasiparticle bands as well as so-called blind bands. Our study is complementary to recent studies of Weyl semimetals with DMFT.