Electric field control of spin lifetimes in Nb-SrTiO${}_3$ by spin-orbit fields

Abstract

We show electric field control of the spin accumulation at the interface of the oxide semiconductor Nb-SrTiO${}_3$ with Co/AlO${}_x$ spin injection contacts at room temperature. The in-plane spin lifetime ${\tau }_{\parallel }$ as well as the ratio of the out-of-plane to in-plane spin lifetime ${\tau }_{\perp }/{\tau }_{\parallel }$ is manipulated by the built-in electric field at the semiconductor surface, without any additional gate contact. The origin of this manipulation is attributed to Rashba Spin-Orbit Fields (SOFs) at the Nb-SrTiO${}_3$ surface and shown to be consistent with theoretical model calculations based on SOF spin flip scattering. Additionally, the junction can be set in a high or low resistance state, leading to a non-volatile control of ${\tau }_{\perp }/{\tau }_{\parallel }$, consistent with the manipulation of the Rashba SOF strength. Such room temperature electric field control over the spin state is essential for developing energy-efficient spintronic devices and shows promise for complex oxide based (spin)electronics

5 pages, 4 figures