Exploring Spin and Topological Phenomena in Complex Oxide Thin Films

Complex oxide materials exhibit a wide range of electronic and magnetic behavior in bulk and thin films. With advances in oxide thin film deposition techniques, we are now able to realize atomically precise thin films, heterostructures and interfaces of these complex oxide materials that open up a new phase space for materials discovery. The stabilization of unusual ground states in such atomically precise complex oxide materials has led to discoveries of novel spin and topological phenomena. In this talk, I describe two recent examples from our group: spin current transfer in ultra-low loss oxide spinels and topologically protected ground states at an oxide interface. The efficient generation and control of spin currents in these oxide spinels make them promising for future low-power electronics such as spin-wave logic devices and voltage controlled magnetic memory. At the metallic LaTiO₃/ SrTiO₃ interface, we have uncovered unexpectedly strong spin-orbit coupling in the form of giant Rashba spin splitting and evidence of a Dirac point. Under electrical gating, we have recently found evidence for topologically protected ground states that is consistent with the quantum spin Hall effect. If true, this would be the first experimentally observed oxide topological insulator.