Absence of a zero-temperature vortex solid phase in strongly disordered superconducting Bi films

We present low-temperature measurements of the resistance in magnetic field of superconducting ultrathin amorphous Bi films with normal-state sheet re sistances, R-N, near the resistance quantum, R-Q=h/e(2). For R-N<R-Q, the t ails of the resistive transitions show the thermally activated flux flow si gnature characteristic of defect motion in a vortex solid with a finite cor relation length. When R-N exceeds R-Q, the tails become nonactivated. We co nclude that in films where R-N>R-Q there is no vortex solid and, hence, no zero resistance state in magnetic field. We describe how disorder induced q uantum and/or mesoscopic fluctuations can eliminate the vortex solid and al so discuss implications for the magnetic-held-tuned superconductor-insulato r transition.