Antiferromagnetic topological insulator state in the correlated Bernevig-Hughes-Zhang model

TL;DR

This paper investigates how electron correlations influence topological phase transitions in the Bernevig-Hughes-Zhang model, revealing the existence of an antiferromagnetic topological insulator phase and characterizing the nature of the magnetic transition.

Contribution

It introduces a variational cluster approach to accurately account for short-range correlations and demonstrates the emergence of an antiferromagnetic topological insulator state.

Findings

Antiferromagnetic topological insulator state exists in the model.

Magnetic transition is of second order.

Topological phase transition involves bulk band gap closing.

Abstract

We study the effects of electron correlations on the topological phase transition in the Bernevig-Hughes-Zhang model using the variational cluster approach where the short-range spatial correlations are taken into account exactly. We calculate the spin Chern number and local magnetic moment to show that the topologically nontrivial antiferromagnetic order exists and that the magnetic transition is of the second order. We furthermore demonstrate that under the spin-quantized condition the topological phase transition is caused by the closing of the bulk band gap.