Singular nonlinear response in metals due to divergent Berry curvature: application to magneto-resistance in metals with type-II Weyl nodes

TL;DR

This paper reveals that in metals with type-II Weyl nodes, the Berry curvature causes a divergent anomaly-related magnetoresistance, highlighting a singular response that can be estimated without full band structure details.

Contribution

It demonstrates that the anomaly-related current near type-II Weyl nodes diverges due to Berry curvature, providing a new way to estimate this current without detailed band structure knowledge.

Findings

Magnetoresistance diverges near type-II Weyl nodes.

Berry curvature enhances contribution from electrons around Weyl nodes.

Potential for estimating anomaly-induced current without full band structure.

Abstract

The physical properties of metals are often given by the sum of the contributions from the electrons consisting the Fermi surface (FS), and therefore, fine structures of the electronic bands and Bloch functions are often masked by the integral over FS. As a consequence, usually, the singular structures in the electronic bands are often not reflected to the macroscopic quantities. In this work, we investigate the anomaly-related magnetoresistance in metals with type-II Weyl nodes close to the FS, and find that the anomaly-related current increases divergently, showing a singular structure. Detailed analysis on a simple model with multiple Weyl nodes shows that the contribution to the magnetoresistance is dominated by the electrons in the vicinity of the Weyl nodes; this is related to the fact that the current is given by the square of the Berry curvature, which enhances the contribution from the electrons around the Weyl nodes. The above results potentially allows an estimate of the anomaly-induced current without precise information of the entire Band structure.