Phase diagram of the attractive Hubbard model with inhomogeneous interactions

Abstract

The phase diagram of the attractive Hubbard model with spatially inhomogeneous interactions is obtained using a single-site dynamical mean-field theory-like approach. The model is characterized by three parameters: the interaction strength, the active fraction (fraction of sites with the attractive interaction), and electron filling. The calculations indicate that in a parameter regime with intermediate values of interaction strength (compared to the bare bandwidth of the electrons), and intermediate values of the active fraction, unconventional superconductivity is obtained. The results of this work are likely to be relevant to many systems with spatially inhomogeneous superconductivity such as strongly correlated oxides, systems with negative U centers, and, in future, cold atom optical lattices.