Cellular Dynamical Mean Field Study on Two-Orbital Hubbard Model with Different Bandwidths

Abstract

We study spin and orbital correlations in the two-orbital Hubbard model with different bandwidths at quarter filling by means of the cellular dynamical mean field theory combined with the noncrossing approximation. We show that the ferromagnetic-antiferro-orbital insulating state is stabilized by the Hund's coupling in the system with the same bandwidths and the antiferromagnetic-ferro-orbital insulating state appears when the difference of bandwidths is quite large. We find that the competition between the two states occurs in the intermediate region and this competition gives rise to the strongly renormalized metallic state.