Dirac charge in antiferromagnetic topological semimetals

TL;DR

This paper uncovers a hidden 'Dirac charge' in antiferromagnetic Dirac semimetals, detectable through photocurrent response, revealing new topological properties and their influence on optoelectronic phenomena.

Contribution

It introduces the concept of Dirac charge in AFM Dirac semimetals and demonstrates its detection via photocurrent, expanding understanding of topological charges in magnetic materials.

Findings

Dirac charge acts as a source or sink of Berry curvature.

Photocurrent driven by spin-charge-coupled motive force reveals Dirac charge.

Real-time simulations show Dirac charge's role in photocurrent generation.

Abstract

Topological node of electronic bands can carry emergent charge degree of freedom such as the Berry curvature monopole of the Weyl semimetals, which results in intriguing transport and optical phenomena. In this study, we discuss the existence of the hidden "Dirac charge" and its detection via the photocurrent response in antiferromagnetic (AFM) Dirac semimetals. In light of the Berry curvature defined in the spin and spin-charge-mixed parameter space, we identify Dirac charges as sources or sinks of the Berry curvature in the generalized parameter space. We demonstrate that this Dirac charge can be detected via the photocurrent driven by the spin-charge-coupled motive force. By using real-time simulation, we find that the Dirac charge plays a significant role in the photocurrent generation in AFM Dirac semimetals. This work reveals the hidden property of the Dirac points in AFM Dirac semimetals.