Exploring Spectral Singularities in Dirac Semimetals: The Role of Non-Hermitian Physics and Dichroism

TL;DR

This paper investigates the spectral singularities and topological properties of Dirac semimetals influenced by non-Hermitian physics, revealing new laser types and the role of axion textures and dichroism.

Contribution

It introduces the first analysis of dichroic DSMs generating 12 topological laser types and clarifies the topological role of the { heta} term in these materials.

Findings

Dichroic DSMs produce 12 unique topological laser types.

Surface currents are generated by topological terms on DSM surfaces.

Topological properties remain stable under external influences.

Abstract

In this study, motivated by recent advancements in non-Hermitian physics, we explore new characteristics of Dirac semimetals (DSMs) using the spectral singularities by means of scattering techniques, with the goal of uncovering additional unique properties. To achieve this, we investigate how the axion texture of a DSM affects its topological properties by analyzing its interaction with electromagnetic waves. We examine the transverse electric (TE) mode configuration, where the magneto-electric effect induces a dichroic property in these materials. This behavior is particularly interesting and commonly seen in potential DSM candidates. Consequently, we report for the first time that a dichroic DSM generates 12 unique topological laser types. We discover that surface currents are generated by topological terms on the surface of the DSM slab. Furthermore, we examine how the {\theta} term associated with axions in topological materials contributes to these topological properties. Our study reveals distinct topological role of the {\theta} term more clearly than ever before. Our results confirm that the topological properties of DSMs with a single Dirac cone remain stable under external influences and that a topologically robust DSM laser can be developed accordingly