Violation of Ohm’s law in a Weyl metal

Abstract

Ohm’s lawis a fundamental paradigm in the electrical transport of metals1. Any transport signatures violating Ohm’s lawwould give an indisputable fingerprint for a novel metallic state. Here, we uncover the breakdown of Ohm’s law owing to a topological structure of the chiral anomaly in the Weyl metal phase. We observe nonlinear I–V characteristics in Bi0.96Sb0.04 single crystals in the diusive limit, which occurs only for a magnetic-field-aligned electric field (EkB). The Boltzmann transport theory with the charge pumping eect reveals the topological-in-origin nonlinear conductivity, and it leads to a universal scaling function of the longitudinal magnetoconductivity, which completely describes our experimental results. As a hallmark ofWeyl metals, the nonlinear conductivity provides a venue for nonlinear electronics, optical applications, and the development of a topological Fermi-liquid theory beyond the Landau Fermi-liquid theory. © 2017 Macmillan Publishers Limited, part of Springer Nature. All rights reserved.