Topological invariants for interacting topological insulators with inversion symmetry

TL;DR

This paper introduces a simplified method to compute Z_2 topological invariants for interacting topological insulators with inversion symmetry, utilizing parity eigenvalues of the Green's function at specific momenta.

Contribution

It presents a new, straightforward topological invariant formula based on parity eigenvalues, simplifying calculations for strongly interacting inversion symmetric insulators.

Findings

The invariant is expressed in terms of parity eigenvalues at time-reversal invariant momenta.

The formula simplifies the calculation of topological invariants in complex interacting systems.

It extends previous results to strongly correlated topological insulators.

Abstract

For interacting Z_2 topological insulators with inversion symmetry, we propose a simple topological invariant expressed in terms of the parity eigenvalues of the interacting Green's function at time-reversal invariant momenta. We derive this result from our previous formula involving the integral over the frequency-momenta space. This formula greatly simplifies the explicit calculation of Z_2 topological invariants in inversion symmetric insulators with strong interactions.