Interface-driven electrical magnetochiral anisotropy in Pt/PtMnGa bilayers

Nonreciprocal charge transport, which is frequently termed as electrical magnetochiral anisotropy (EMCA) in chiral conductors, touches the most important elements of modern condensed matter physics. Here, we have investigated the EMCA in Pt/PtMnGa (PMG) bilayers with the assitance of nonequilibrium fluctuation theorems. Large EMCA in the Pt/PMG bilayers can be attributed to nonreciprocal response of an interface-driven chiral transport channel. Due to the presence of large charge fluctuations for small current region, higher order EMCA coefficients should be added and they are all functions of current. A combination of asymmetrical electron scattering and spin-dependent scattering furnish the PMG thickness dependent chiral transport behaviors in Pt/PMG bilayers. The dramatically enhanced anomalous Hall angle of PMG further demonstrates the modified surface state properties by strong spin-orbit coupling.