Chiral anomaly and giant magnetochiral anisotropy in noncentrosymmetric Weyl semimetals

TL;DR

This paper theoretically demonstrates that noncentrosymmetric Weyl semimetals can exhibit giant magnetochiral anisotropy due to the chiral anomaly, with potential applications in rectifier devices.

Contribution

It derives a formula for the magnetochiral anisotropy coefficient in noncentrosymmetric Weyl semimetals, highlighting the enhancement near Weyl points and potential for larger effects than in other materials.

Findings

Magnetochiral anisotropy is strongly enhanced near Weyl points.

Noncentrosymmetric Weyl semimetals like TaAs can exhibit large magnetochiral effects.

Derived formula predicts significant anisotropy enhancement in specific conditions.

Abstract

We theoretically propose that giant magnetochiral anisotropy is achieved in Weyl semimetals in noncentrosymmetric crystals as a consequence of the chiral anomaly. The magnetochiral anisotropy is the nonlinearity of the resistivity $\rho$ that depends on the current $\boldsymbol{I}$ and the magnetic field $\boldsymbol{B}$ as $\rho=\rho_0 (1 + \gamma \boldsymbol{I} \cdot \boldsymbol{B})$, and can be applied to rectifier devices controlled by $\boldsymbol{B}$. We derive the formula for the coefficient $\gamma$ in noncentrosymmetric Weyl semimetals. The obtained formula for $\gamma$ shows that the magnetochiral anisotropy is strongly enhanced when the chemical potential is tuned to Weyl points, and that noncentrosymmetric Weyl semimetals such as TaAs can exhibit much larger magnetochiral anisotropy than that observed in other materials so far.