Dynamics of electric transport in interacting Weyl semimetals

TL;DR

This paper investigates the unique electric transport properties of interacting Weyl semimetals, revealing slow current decay, large dielectric response, and the impact of Coulomb interactions on AC conductivity.

Contribution

It provides a detailed analysis of the AC and DC transport response in Weyl semimetals, highlighting the effects of strong spin-orbit coupling and Coulomb interactions on conductivity.

Findings

DC conductivity vanishes in clean Weyl semimetals.

AC conductivity has a real part linear in frequency and a logarithmically increasing imaginary part.

Strong Coulomb interactions significantly modify transport properties.

Abstract

The response to an electric field (DC and AC) of electronic systems in which the Fermi "surface" consists of a number of 3D Weyl points (such as some pyrochlore iridates) exhibits a peculiar combination of characteristics usually associated with insulating and conducting behaviour. Generically a neutral plasma in clean materials can be described by a tight binding model with a strong spin-orbit interaction. A system of that type has a vanishing DC conductivity; however the current response to the DC field is very slow: the current decays with time in a powerwise manner, different from an insulator. The AC conductivity, in addition to a finite real part which is linear in frequency, exhibits an imaginary part that increases logarithmically as function of the UV cutoff (atomic scale). This leads to substantial dielectric response like a large dielectric constant at low frequencies. This is in contrast to a 2D Weyl semimetal like graphene at neutrality point where the AC conductivity is purely pseudo-dissipative. The Coulomb interaction between electrons is long range and sufficiently strong to make a significant impact on transport. The interaction contribution to the AC conductivity is calculated within the tight binding model.