Crystal-induced transverse current in collinear antiferromagnetic gamma-FeMn

Based on first-principles calculations, we predict a giant crystal-induced transverse current in antiferromagnetic gamma-FeMn. This abnormal transverse current cannot be understood by the conventional anomalous Hall effect (e.g., Berry curvature, skew scattering, and side jump), which widely exists in ferromagnetic and antiferromagnetic materials. Moreover, the efficiency of the transverse current generation therein can be as large as 18.4% at low temperatures; this is an order of magnitude larger than the anomalous Hall angle in conventional ferromagnetic materials, such as Fe or Fe-based alloys. Furthermore, using the Boltzmann transport equation and a tight-binding model, we conclude that the asymmetric group velocities on the Fermi surface are the origin of this crystal-induced transverse current in gamma-FeMn. Additionally, with a systematic discussion, we show that this unusual effect is not dependent on specific materials but is universal in any crystal with anisotropic symmetry.