Topological Order Parameters for Interacting Topological Insulators

TL;DR

This paper introduces a new topological order parameter based on Green's functions for interacting topological insulators, which is exactly quantized and experimentally measurable, aiding in phase diagram determination for complex systems.

Contribution

It presents a novel topological order parameter applicable to interacting and disordered topological insulators, quantized for time reversal invariant systems, and measurable via the magneto-electric effect.

Findings

Order parameter is exactly quantized in time reversal invariant insulators.

Can be experimentally measured through topological magneto-electric effect.

Applicable to both interacting and disordered systems.

Abstract

We propose a topological order parameter for interacting topological insulators, expressed in terms of the full Green's functions of the interacting system. We show that it is exactly quantized for a time reversal invariant topological insulator, and it can be experimentally measured through the topological magneto-electric effect. This topological order parameter can be applied to both interacting and disordered systems, and used for determining their phase diagrams.