Spin-orbit coupled superconductivity at the interface of LaAlO3/SrTiO3

By using oxide MBE technique, we have grown few monolayers of epitaxial LaAlO$_3$ (LAO) on TiO2 terminated SrTiO$_3$ (STO) substrates, which shows an interface superconductivity below about 0.3 K. Scanning tunneling electron microscope images revealed a sharp atomic interface between LAO and STO in our LAO/STO samples. By fabricating a back gate electrode via the STO substrate, the superconductor‐insulator transition was observed by applying gate voltages on a macroscopic size of the two‐dimensional electron liquid (2DEL) at the interface of LAO/STO. From the superconducting critical field anisotropy measurements, a sizable spin‐orbit coupling (SOC) is likely to present in the superconducting phase, where the upper limit of the SOC strength can be largely tuned by gate voltages. In addition, magneto‐transport anomaly was found when depleting the electron density and thus driving the 2DEL into insulating phase, suggesting an inhomogeneous density distribution and also a possible multi‐band conduction in the 2DEL.