Quantum transport in Dirac materials: signatures of tilted and anisotropic Dirac and Weyl cones

TL;DR

This paper investigates how tilt and anisotropy in Dirac and Weyl materials influence quantum transport properties, revealing that tilt uniquely affects both conductance and noise, with implications for understanding these materials.

Contribution

It provides a comprehensive analysis of conductance and noise in tilted and anisotropic Dirac/Weyl cones, highlighting the distinct effects of tilt and anisotropy on transport properties.

Findings

Anisotropy affects conductance but not Fano factor.

Tilt influences both conductance and Fano factor.

Universal Fano factor remains unchanged under anisotropy.

Abstract

We calculate conductance and noise for quantum transport at the nodal point for arbitrarily tilted and anisotropic Dirac or Weyl cones. Tilted and anisotropic dispersions are generic in absence of certain discrete symmetries, such as particle-hole and lattice point group symmetries. Whereas anisotropy affects the conductance g, but leaves the Fano factor F (the ratio of shot noise power and current) unchanged, a tilt affects both g and F. Since F is a universal number in many other situations, this finding is remarkable. We apply our general considerations to specific lattice models of strained graphene and a pyrochlore Weyl semi-metal.