AC conductivity and magnetic dichroism of two-dimensional antiferromagnetic Dirac semimetals

TL;DR

This paper studies the magneto-optical properties of two-dimensional antiferromagnetic Dirac semimetals, specifically CuMnAs, showing how N{\'e}el order affects optical responses and proposing magnetic linear dichroism spectroscopy to determine N{\'e}el vector orientation.

Contribution

It provides a theoretical analysis of the magneto-optical response of 2D antiferromagnetic Dirac semimetals and introduces magnetic linear dichroism spectroscopy as a tool to identify N{\'e}el vector orientation.

Findings

N{\'e}el order orientation influences magneto-optical response.

Magnetic linear dichroism varies with N{\'e}el vector direction.

Spectroscopy can determine N{\'e}el vector orientation.

Abstract

We investigate the magneto-optical properties of two-dimensional nonsymmorphic Dirac semimetals in the presence of antiferromagnetic order. Using the Kubo formula, we calculate the conductivity tensor of two-dimensional CuMnAs, a prototype antiferromagnetic Dirac material, as a function of light frequency. From the finite-frequency conductivity tensor, we derive the dynamic dielectric function and magnetic linear dichroism, demonstrating how they are influenced by the orientation of the N{\'e}el order parameter. Adjusting the N{\'e}el vector changes both the sign and amplitude of the system's magneto-optical response. We propose that magnetic linear dichroism spectroscopy is a powerful technique for determining the orientation of the N{\'e}el vector.