Evolution of the Density of States Gap in a Disordered Superconductor
Carey Huscroft, Richard T. Scalettar
We determine the effect of a random potential on the density of states $N(\ensuremath{\omega})$ in the attractive Hubbard model. At weak coupling, disorder closes the gap concurrently with the destruction of superconductivity. At larger, but still intermediate coupling, a pseudogap in $N(\ensuremath{\omega})$ remains beyond the point at which off-diagonal long range order vanishes. This change in the elementary excitations of the insulating phase corresponds to a crossover between Fermi and Bose insulators.
arXiv:cond-mat/9804122•Physical Review Letters•Sep 28, 1998•32 citations