Disorder-Induced Inhomogeneities of the Superconducting State Close to   the Superconductor-Insulator Transition
  Scanning tunneling spectroscopy at very low temperature on homogeneously disordered superconducting Titanium Nitride thin films reveals strong spatial inhomogeneities of the superconducting gap $\Delta$ in the density of states. Upon increasing disorder, we observe suppression of the superconducting critical temperature $T_c$ towards zero, enhancement of spatial fluctuations in $\Delta$, and growth of the $\Delta/T_c$ ratio. These findings suggest that local superconductivity survives across the disorder-driven superconductor-insulator transition. 
B. Sacepe, C. Chapelier, T. I. Baturina, V. M. Vinokur, M. R. Baklanov   and M. Sanquer