Superconductivity and the electronic density of states in disordered two-dimensional metals

Abstract

We have measured the superconducting and normal-state properties of ultrathin quench-condensed Pb and Sn films by electron tunneling and transport. The normal-state measurements illustrate a substantial reduction in the electronic density of states about the Fermi surface. Good agreement with theory is obtained for this reduction. The collapse of $T_c$ can be accounted for by the reduced density of states but some problems stand in the way of a full description of the superconducting behavior.