Circular dichroism of chiral Majoranas

TL;DR

This paper investigates the circular dichroism caused by chiral Majorana states in hybrid quantum structures, proposing optical absorption spectroscopy as a novel method to detect these topological states.

Contribution

It introduces the calculation of circular dichroism in chiral Majoranas within hybrid quantum structures, highlighting its potential as a detection technique.

Findings

Absorption peaks are equally spaced with positive and negative dichroism.

Long structures favor peaks of a single sign.

Circular dichroism spectroscopy can serve as a probe for chiral Majoranas.

Abstract

Majorana states in condensed matter devices may be of a localized nature, such as in hybrid semiconductor/superconductor nanowires, or chirally propagating along the edges such as in hybrid 2D quantum-anomalous-Hall/superconductor structures. We calculate the circular dichroism due to chiral Majorana states in a hybrid structure made of a quantum-anomalous-Hall-insulator and a superconductor. The optical absorption of chiral Majoranas is characterized by equally spaced absorption peaks of both positive and negative dichroism. In the limit of a very long structure (a 2D ribbon) peaks of a single sign are favored. Circular-dichroism spectroscopy of chiral Majoranas is suggested as a relevant probe for these peculiar states of topological matter.