Precise determination of critical points of topological phase transitions via shift current in two-dimensional inversion asymmetric insulators

TL;DR

This paper reveals that the sign reversal of shift current tensor components at topological phase transitions in 2D inversion asymmetric insulators can precisely identify critical points, independent of temperature effects.

Contribution

It introduces a novel method using shift current sign reversal to accurately determine topological phase transition points in 2D insulators.

Findings

Shift current tensor components reverse sign at topological transitions

Sign reversal occurs regardless of temperature variations

Method applicable to various materials and transition types

Abstract

The precise determination of critical point is the basis to extract various critical properties of phase transitions. We identify that for two-dimensional inversion asymmetric insulators, with and without time-reversal symmetry, when topological phase transitions take place, all nonvanishing components of band-edge shift current tensor will reverse their signs in a singular way, regardless of what realistic value the temperature takes. This remarkable sign-reversal behavior of band-edge shift current tensor thus can be applied to determine the critical points of various topological phase transitions precisely, even for temperature-driven ones. We suggest concrete materials to test our predictions.