SFB Extra Seminar

Active search is being pursued for alternatives to our current silicon technology and  transition metal oxides  heterostructures are valuable in this respect since they can now be engineered in a Lego-like fashion. It has been shown that their interfaces are not only conducting but that they also exhibit ferroelectricity, superconductivity, gate tunable transport, large thermoelectric effect, large spin-orbit contributions, possibly ferromagnetism as well. Given this multifunctionality, oxide electronics (we coined it "oxitronics") appears to be a promising lead for new types of components, notably in regards to spintronics.

We shall  focus on oxide based heterostructures for which one of the constitutive materials is SrTiO3 (STO). Experiments reveal that a  quasi two-dimensional metallic sheet that evolves at low temperature into a superconducting state may form on the STO side, close to the interface. Charge transport can be controlled by applying gate voltages which also  tune the strength of the interfacial spin-orbit  interaction (Rashba) . Strain and spin also impact the transport of charge. The existence of a two-dimensional topological metallic state was theoretically proposed in such systems and fingerprints of this regime have recently been experimentally evidenced through a giant spin to charge conversion (inverse Rashba-Edelstein effect), quantized plateaus in the Hall conductance of LAO-STO mesoscopic devices and also in edge transport of LaTiO3-SrTiO3 Hall bars.

M. Vivek et al., Phys. Rev. B 95, 165117 (2017)
A Spin-Orbit Playground: Surfaces and Interfaces of Transition Metal Oxides
S. Gariglio, A. D. Caviglia, J-M. Triscone, M. Gabay, Reports of Progress in Physics, 82, 012501(2019)
D. C. Vaz, et al., Nature Materials vol 18, 1187–1193(2019)