Giant Magnetochiral Anisotropy in Weyl-semimetal WTe2 Induced by Diverging Berry Curvature

TL;DR

This paper demonstrates that diverging Berry curvature at Weyl points in WTe2 significantly enhances magnetochiral anisotropy, achieving record figures of merit in bulk materials, linking Berry curvature to nonreciprocal transport.

Contribution

It reveals the role of Berry curvature in amplifying magnetochiral anisotropy in Weyl semimetal WTe2, with experimental and theoretical evidence showing the effect near Weyl points.

Findings

Maximal figure of merit $ar{ ext{γ}}$ reaches $1.2 imes 10^{-6}$ m²T⁻¹A⁻¹, the largest in bulk materials.

Strong enhancement of magnetochiral anisotropy observed when Fermi level is near Weyl points.

Semiclassical calculations confirm diverging Berry curvature at Weyl points boosts anisotropy.

Abstract

The concept of Berry curvature is essential for various transport phenomena. However, an effect of the Berry curvature on magnetochiral anisotropy, i.e. nonreciprocal magneto-transport, is still elusive. Here, we report the Berry curvature originates the large magnetochiral anisotropy. In Weyl-semimetal WTe2, we observed the strong enhancement of the magnetochiral anisotropy when the Fermi level is located near the Weyl points. Notably, the maximal figure of merit $\bar{\gamma}$ reaches $1.2\,{\times}10^{-6} \rm{m^2T^{-1}A^{-1}}$, which is the largest ever reported in bulk materials. Our semiclassical calculation shows that the diverging Berry curvature at the Weyl points strongly enhances the magnetochiral anisotropy.