Edge optical effect as a probe of chiral topological superconductors

TL;DR

This paper demonstrates that the optical response of chiral topological superconductors reveals in-gap resonances linked to their topological properties, providing a new way to identify different topological phases.

Contribution

It introduces a method to detect chiral Bogoliubov edge states via optical effects, correlating resonance peaks with the Chern number of the superconductor.

Findings

Optical absorption peaks are determined by the Chern number.

Linear optical response can distinguish topological phases.

Method applies to superconductor-quantum anomalous Hall insulator junctions.

Abstract

We study the optical effect of chiral topological superconductors in two dimensions. The linear optical response from chiral Bogoliubov edge modes in clean superconductors has in-gap resonances, which is originated from the transitions within the edge particle-hole pair bands. Interestingly, the number of resonance peaks is determined by the Bogoliubov-de Gennes Chern number of topological superconductors. Such a sharply distinctive feature in optical absorption offers a simple way to distinguish topological superconductors with different Chern numbers. We further demonstrate that linear optical effect could probe different topological phases in quantum anomalous Hall insulator-superconductor junction devices. This finding provides an applicable method to detect chiral Bogoliubov edge states and is distinguishable from collective modes in superconductors and possible trivial explanations.