Magnetotransport and internodal tunnelling in Weyl semimetals

TL;DR

This paper investigates how internodal tunnelling affects magnetotransport in Weyl semimetals, revealing a strong angular dependence of resistivity influenced by magnetic field strength and quasiparticle scattering.

Contribution

It provides a microscopic calculation of longitudinal resistivity considering internodal tunnelling and impurity scattering, highlighting the angular dependence and exponential magnetic field dependence.

Findings

Resistivity exhibits a $ ho( heta) o C_1 + C_2 ext{cos}^2 heta$ dependence.

Internodal tunnelling contribution is significant near $ heta o rac{ ext{pi}}{2}$ and depends exponentially on magnetic field.

Second term of resistivity is weakly dependent on magnetic field over a broad range.

Abstract

Internodal dynamics of quasiparticles in Weyl semimetals manifest themselves in hydrodynamic, transport and thermodynamic phenomena and are essential for potential valleytronic applications of these systems. In an external magnetic field, coherent quasiparticle tunnelling between the nodes modifies the quasiparticle dispersion and, in particular, opens gaps in the dispersion of quasiparticles at the zeroth Landau level. We study magnetotransport in a Weyl semimetal taking into account mechanisms of quasiparticle scattering both affected by such gaps and independent of them. We compute the longitudal resistivity of a disordered Weyl semimetal with two nodes in a strong magnetic field microscopically and demonstrate that in a broad range of magnetic fields it has a strong angular dependence $\rho(\eta)\propto C_1+C_2 \cos^2\eta$, where $\eta$ is the angle between the field and the separation between the nodes in momentum space. The first term is determined by the coherent internodal tunnelling and is important only at angles $\eta$ close to $\pi/2$. This contribution depends exponentially on the magnetic field, $\propto \exp\left(-B_0/B\right)$. The second term is weakly dependent on the magnetic field for realistic concentrations of the impurities in a broad interval of fields.