An intrinsic nonlinear Ohmic current

TL;DR

This paper introduces a new intrinsic nonlinear Ohmic current in magnetic metals arising from Berry connection polarizability, breaking time-reversal symmetry, with potential applications in Dirac systems.

Contribution

It identifies a novel intrinsic nonlinear current mechanism distinct from known types, linked to Berry connection polarizability and applicable in specific magnetic point groups.

Findings

66 magnetic point groups support this nonlinear current

Proposed candidate materials exhibit the effect

Demonstrated in 1D and 2D Dirac systems

Abstract

It is known that intrinsic currents in magnetic metals often appear in the direction perpendicular to the external field for linear and nonlinear responses. Distinct from three kinds of known nonlinear currents, namely, the Drude contribution, the Berry curvature dipole induced current and the Berry connection polarization induced current, here we report a intrinsic nonlinear current with breaking time-reversal symmetry. This new kind of intrinsic nonlinear current from the nontrivial Berry connection polarizability may emerge in the longitudinal or transverse direction, and both are dissipative Ohmic currents. We unveil 66 magnetic point group symmetries that can accommodate such nonlinear current, and possible candidate materials are proposed. This theory is also applied to observe the nonlinear current we proposed in one- and two-dimensional Dirac systems as examples.