Fermi arcs and DC transport in nanowires of Dirac and Weyl semimetals

TL;DR

This paper investigates the unique surface and bulk electron transport properties in nanowires of Dirac and Weyl semimetals, emphasizing the role of Fermi arcs in nonuniform charge distribution and surface-dominated conductivity.

Contribution

It provides a detailed analysis of surface Fermi arc effects on DC transport in Dirac and Weyl semimetal nanowires, highlighting the surface's dominant role at low chemical potentials.

Findings

Charge density is mainly accumulated at the surface due to Fermi arcs.

Surface states significantly influence DC conductivity, especially at low chemical potentials.

Surface conductivity exhibits peaks when the Fermi level crosses surface state energies.

Abstract

The transport properties and electron states in cylinder nanowires of Dirac and Weyl semimetals are studied paying special attention to the structure and properties of the surface Fermi arcs. The latter make the electric charge and current density distributions in nanowires strongly nonuniform as the majority of the charge density is accumulated at the surface. It is found that a Weyl semimetal wire also supports a magnetization current localized mainly at the surface because of the Fermi arcs contribution. By using the Kubo linear response approach, the direct current (DC) conductivity is calculated and it is found that its spatial profile is nontrivial. By explicitly separating the contributions of the surface and bulk states, it is shown that when the electric chemical potential and/or the radius of the wire is small, the electron transport is determined primarily by the Fermi arcs and the electrical conductivity is much higher at the surface than in the bulk. Due to the rise of the surface-bulk transition rate, the relative contribution of the surface states to the total conductivity gradually diminishes as the chemical potential increases. In addition, the DC conductivity at the surface demonstrates noticeable peaks when the Fermi level crosses energies of the surface states.