Electrical magnetochiral anisotropy and quantum metric in chiral conductors

Abstract: Electrical magnetochiral anisotropy (EMCA) refers to the chirality- and current-dependent nonlinear magnetoresistance in chiral conductors and is commonly interpreted in a semiclassical picture. In this work, we reveal a quantum geometry origin of EMCA using a chiral rectangular lattice model that resembles a chiral organic conductor (DM-EDT-TTF)${}_2$ClO${}_4$ studied for EMCA recently and exhibits symmetry-protected Dirac bands similar to those of graphene. Compared to the semiclassical term, we find that Dirac states contribute significantly to both traditional longitudinal EMCA and the unconventional transverse EMCA via the quantum metric when Fermi energy is close to the Dirac point. Besides, we discover that a topological insulator state can emerge once spin-orbit coupling (SOC) is added to our chiral model lattice. Our work paves a path toward understanding quantum geometry in the magnetotransport of chiral materials.