Anomalous Surface Conductivity of Weyl Semimetals

TL;DR

This paper predicts an anomalous, temperature- and doping-independent contribution to the surface conductivity of Weyl semimetals, arising from bulk effects, which can be experimentally observed to understand their unique surface behavior.

Contribution

It introduces a novel anomalous surface conductivity component in Weyl semimetals, linked to bulk contributions, distinct from traditional Fermi arc effects.

Findings

Anomalous surface conductivity is independent of surface scattering time.

Surface conductivity increases quadratically with temperature and doping.

The anomalous contribution dominates at low temperatures, revealing unusual surface physics.

Abstract

We calculate the surface dc conductivity of Weyl semimetals and show that it contains an anomalous contribution in addition to a Drude contribution from the Fermi arc. The anomalous part is independent of the surface scattering time, and appears at nonzero temperature and doping (away from the Weyl nodes), increasing quadratically with both with a universal ratio of coefficients. Microscopically, it results from the contribution of the gapless bulk to the surface conductivity. We argue that this can be interpreted as the conductivity of an effective interacting surface fluid that coexists with the Fermi arc metal. In a certain regime of low temperatures, the temperature dependence of the surface conductivity is dominated by the anomalous response, which can be probed experimentally to unravel the unusual behavior.