Tuning superconductivity at the Al2O3/SrTiO3-interface with light

The 2-DEG at SrTiO3-based interfaces is sensitive to illumination with visible light [1], which at low temperatures can be used to tune the transition temperature of the superconducting state in a nonvolatile manner [2]. We present studies on an Al2O3/SrTiO3 sample with micro bridges running along different crystallographic directions at the interface. We are able to tune the low temperature conductance by illuminating the sample and reverse the altered state by thermal treatment at low temperatures (T < 15 K). Transport measurements in dependence of the magnetic field and temperature are conducted in different states, characterized by the tunable but time independent re- sistance at 1 K. The Berezinskii-Kosterlitz-Thouless transition in this system can be addressed by the current voltage behavior, which simultaneously gives further information on the inhomogeneous nature of the superconducting phase.
[1]: M. Yazdi-Rizi et al, PRB 95 (2017)
[2]: D. Arnold et al, APL 115 (2019)