Thickness-Magnetic Field Phase Diagram at the Superconductor-Insulator Transition in 2D

TL;DR

This paper maps the phase diagram of the superconductor-insulator transition in ultrathin amorphous Bi films as a function of thickness and magnetic field at zero temperature, providing new insights into critical behavior.

Contribution

It presents the first experimental phase diagram at T=0 for the transition, including critical exponents for both zero and finite magnetic field cases.

Findings

Critical exponent product vz=1.2 at zero field

Critical exponent product vz=1.4 at finite field

Exponents differ from magnetic field tuned transition in the same system

Abstract

The superconductor-insulator transition in ultrathin films of amorphous Bi was tuned by changing the film thickness, with and without an applied magnetic field. The first experimentally obtained phase diagram is mapped as a function of thickness and magnetic field in the T=0 limit. A finite size scaling analysis has been carried out to determine the critical exponent product vz, which was found to be 1.2 for the zero field transition, and 1.4 for the finite field transition. Both results are different from the exponents found for the magnetic field tuned transition in the same system, 0.7.