Delft University of Technology

Title: Superconductor-Insulator Transitions in 2D

Abstract: The superconductor-insulator transition has been studied on ultrathin films of bismuth, deposited on liquid helium cooled substrates. The transition was tuned by changing both the film thickness and the magnetic field on the same set of films. Assuming that the transition is controlled by a T=0 critical point, a finite size scaling analysis has been carried out to determine the correlation length exponent \nu and the dynamical critical exponent z. The phase diagram and the critical resistance have been studied as a function of film thickness and magnetic field. The results are discussed in terms of bosonic models of the superconductor-insulator transition, as well as recent percolation models which predict finite dissipation at T=0.