Large anomalous magnetic moment in three-dimensional Dirac and Weyl semimetals

TL;DR

This paper explores how Coulomb interactions influence the electromagnetic response of 3D Dirac and Weyl semimetals, revealing significant anomalous magnetic moments and effects on topological surface states, with potential for experimental observation.

Contribution

It uncovers three distinct effects of Coulomb interactions on the anomalous magnetic moment and surface states in Dirac and Weyl semimetals, extending quantum electrodynamics insights to condensed matter.

Findings

Anomalous magnetic moment is finite and larger than Schwinger's prediction at nonzero doping.

Identification of three distinct effects of Coulomb interactions on quasiparticles.

Effects on topological surface states at the vacuum-semimetal interface.

Abstract

We investigate the effect of Coulomb interactions on the electromagnetic response of three-dimensional Dirac and Weyl semimetals. In a calculation reminiscent of Schwinger's seminal work on quantum electrodynamics, we find three physically distinct effects for the anomalous magnetic moment of the relativisticlike quasiparticles in the semimetal. In the case of nonzero doping, the anomalous magnetic moment is finite at long wavelengths and typically orders of magnitude larger than Schwinger's result. We also find interesting effects of one of the three new Hamiltonian terms on the topological surface states at the interface between vacuum and a Weyl semimetal. We conclude that observation of these effects should be within experimental reach.