| Abstract: | The Superconductor Insulator Transition (SIT) in 2D layers and thin films has been a topic of great interest for the past few decades. While much progress has been made in the field, both theoretically and experimentally, there are still important open questions, such as the possible existence of an intermediate anomalous metal phase and the nature of the insulating phase.
Several tuning parameters have been used in the past to drive the transition, including thickness, disorder, magnetic field, chemical composition etc. I will present a new tuning parameter, i.e., hydrostatic pressure, to gain further information on the electric properties close to the transition, and especially on the insulating and metallic phases. For this purpose, we grow thin films of amorphous Indium Oxide directly on a diamond which is part of a high-pressure Diamond Anvil Cell, thus enabling us to apply pressure of up to ~20 GPa on a thin disordered film. Starting with an insulating film we find that initially, up to ~1.5GPa, pressure induces a transition to a superconducting state with growing critical temperature. However, applying higher pressure causes a suppression of superconductivity and drives the film back to an insulating state through an apparent metallic phase. Interestingly, the electronic properties of the pressure-induced insulator are different than those of the insulator in ambient conditions. I will discuss the implications of these results on the nature of superconductivity in highly disordered 2D superconductors and on the presence of an anomalous metal state. |