Electrically controlled persistent spin currents at the interface of multiferroic oxides

We predict the appearance of a persistent spin current in a two-dimensional electron gas formed at the interface of multiferroic oxides with a transverse helical magnetic order. No charge current is generated. This is the result of an effective spin-orbit coupling generated by the topology of the oxide local magnetic moments. The effective coupling and the generated spin current depend linearly on the magnetic spiral helicity which, due to the magneto-electric coupling, is tunable by a transverse electric field offering thus a new mean for the generation of electrically controlled persistent spin currents.