Electrostatically Tuned Superconductor-Insulator Transition in Indium Oxide Thin Films

Recently the ``standard paradigm" which assumes that in the presence of disorder, and in the limit of zero temperature, the two-dimensional (2D) electron may exhibit either an insulating or a superconducting ground state, has been challenged both, theoretically and experimentally. In this paper we study amorphous Indium Oxide (InO$_x$) thin films that are fabricated by electron beam evaporation on SrTiO$_3$. By annealing in vacuum, air or oxygen atmosphere the room temperature sheet resistance of the samples is varied. Applying an external electrostatic field (using back-gating) and magnetic fields at low temperatures, the samples are tuned, between a superconducting and an insulating states. Sheet resistance and Hall effect are measured at low temperatures gaining further insights into the superconductor-metal-insulator transitions (SIT) in this system.