Robustness of anomaly-related magnetoresistance in doped Weyl semimetals

TL;DR

This paper demonstrates that the negative magnetoresistance linked to the chiral anomaly in Weyl semimetals remains robust despite deviations like Fermi level shifts and nonlinear dispersions, highlighting the phenomenon's resilience.

Contribution

It shows that the anomaly-related magnetoresistance persists even with Fermi energy shifts and node pair annihilation, extending understanding of Weyl semimetal behavior.

Findings

Magnetoresistance persists with Fermi level shifts.

Robustness of magnetoresistance beyond ideal Weyl conditions.

Persistence after Weyl node pair annihilation.

Abstract

Weyl semimetal with Weyl fermions at Fermi energy is one of the topological materials, and is a condensed-matter realization of the relativistic fermions. However, there are several crucial differences such as the shift of Fermi energy, which can hinder the expected interesting physics. Chiral anomaly is a representative nontrivial phenomenon associated with Weyl fermions, which dictates the transfer of fermions between the Weyl fermions with opposite chirality; it is manifested as the negative magnetoresistance. Here we demonstrate that the magnetoresistance is robust against the deviation from the ideal Weyl Hamiltonian such as the shifted Fermi energy and nonlinear dispersions. We study a model with the energy dispersion containing two Weyl nodes, and find that the magnetoresistance persists even when the Fermi level is far away from the node, even above the saddle point that separates the two nodes. Surprisingly, the magnetoresistance remains even after the pair annihilation of the nodes.