Chirality from interfacial spin-orbit coupling effects in magnetic bilayers
Kyoung-Whan Kim, Hyun-Woo Lee, Kyung Jin Lee, Mark D. Stiles
Spin-orbit coupling causes many properties that make magnets technologically important as well as properties that interfere with optimal performance. As nanomagnetic devices scale to smaller sizes, spin-orbit coupling due to the broken structural inversion symmetry at interfaces becomes increasingly important. Here we use a minimal two-dimensional model of itinerant electrons near the interface to show that the interfacial spin-orbit coupling generates chiral effects such as the interfacial Dzyaloshinskii-Moriya interaction, chiral spin torques, and spin-dependent chiral electromagnetic fields. All these effects are mutually correlated and are related through a curved space description. The latter reveals the frustration in magnetic ground state. In magnetic bilayers, these chiral effects lead to very efficient current-induced magnetization dynamics. Such effects may also be relevant for high-mobility two-dimensional electron gas at the interface between insulating oxides.