Electric-Field Control of Spin Current Generation and Detection in Ferromagnet-Free SrTiO₃-Based Nanodevices.

Abstract

Spintronics entails the generation, transport, manipulation and detection of spin currents, usually in hybrid architectures comprising interfaces whose impact on performance is detrimental. In addition, how spins are generated and detected is generally material specific and determined by the electronic structure. Here, we demonstrate spin current generation, transport and electrical detection, all within a single non-magnetic material system: a SrTiO₃ two-dimensional electron gas (2DEG) with Rashba spin-orbit coupling. We show that the spin current is generated from a charge current by the 2D spin Hall effect, transported through a channel and reconverted into a charge current by the inverse 2D spin Hall effect. Furthermore, by adjusting the Fermi energy with a gate voltage we tune the generated and detected spin polarization and relate it to the complex multiorbital band structure of the 2DEG. We discuss the leading mechanisms of the spin-charge interconversion processes and argue for the potential of quantum oxide materials for future all-electrical low-power spin-based logic.