Topological Mott Insulators

TL;DR

This paper investigates how extended Hubbard models on a honeycomb lattice can host topological Mott insulators exhibiting quantum Hall effects, driven by frustrating second-neighbor interactions, with analysis via mean-field, RPA, and renormalization group methods.

Contribution

It demonstrates the emergence of topological Mott phases in extended Hubbard models due to frustrating interactions, supported by multiple theoretical approaches.

Findings

Topological Mott phases can arise from second-neighbor repulsive interactions.

Mean-field phase diagram shows regions of topological insulators.

RPA and renormalization group analyses support the stability of these phases.

Abstract

We consider extended Hubbard models with repulsive interactions on a Honeycomb lattice and the transitions from the semi-metal phase at half-filling to Mott insulating phases. In particular, due to the frustrating nature of the second-neighbor repulsive interactions, topological Mott phases displaying the quantum Hall and the quantum spin Hall effects are found for spinless and spinful fermion models, respectively. We present the mean-field phase diagram and consider the effects of fluctuations within the random phase approximation (RPA). Functional renormalization group analysis also show that these states can be favored over the topologically trivial Mott insulating states.