Title: Pressure-induced superconductor-insulator-transition.

Abstract of the talk:
The Superconductor Insulator Transition (SIT) in 2D 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 a possible in-direct transition through an anomalous metal phase and the nature
of the insulating phase, which exhibits a number of peculiar findings. Several tuning
parameters have been used in the past to drive the transition, including thickness,
disorder, magnetic field, chemical composition etc. We utilize a new tuning
parameter, hydrostatic pressure, to gain further information on the electric properties
close to the transition, and, in particular, on the insulating phase.
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 Tc. However, higher pressure suppresses
superconductivity and drives the film back to an insulating state. Interestingly, the
electronic properties of the pressure-induced insulator are different than those of the
ambient one. I discuss the implications of these results on the nature of
superconductivity in highly disordered 2D superconductors.

 

All are welcome.