Dynamic current-current susceptibility in 3D Dirac and Weyl semimetals

TL;DR

This paper analytically investigates the dynamic current-current response in 3D Dirac and Weyl semimetals, revealing how their optical and magnetic properties are affected by external fields and chiral anomaly effects.

Contribution

It provides an analytical calculation of the wave-vector and frequency dependent response functions, including plasmon dispersion and orbital magnetic susceptibility, highlighting effects of parallel electric and magnetic fields.

Findings

Analytical expressions for current-current response functions.

Impact of ${f E} imes{f B}$ fields on response functions.

Potential experimental signatures of chiral anomaly.

Abstract

We study the linear response of doped three dimensional Dirac and Weyl semimetals to vector potentials, by calculating the wave-vector and frequency dependent current-current response function analytically. The longitudinal part of the dynamic current-current response function is then used to study the plasmon dispersion, and the optical conductivity. The transverse response in the static limit yields the orbital magnetic susceptibility. In a Weyl semimetal, along with the current-current response function, all these quantities are significantly impacted by the presence of parallel electric and magnetic fields (a finite ${\bf E}\cdot{\bf B}$ term), and can be used to experimentally explore the chiral anomaly.