Superfluid-insulator transition of two-band fermionic atom systems in optical lattices

Abstract

We study the multiband effects on ultracold fermionic atoms in optical lattices by two-site dynamical mean-field theory. We find that the density wave state becomes stable for a small orbital splitting region. As the orbital splitting is increased, the transition from the density wave state to the superfluid state occurs. By systematically changing the orbital splitting and the attractive interaction, we obtain the phase diagram at half-filling.