FisMat2017 - Submission - View

Abstract's title: Mott transition and anti-ferro orbital ordering in a two band Hubbard model
Submitting author: Francesco Grandi
Affiliation: SISSA
Affiliation Address: Via Bonomea, 265, 34136 Trieste
Country: Italy
Oral presentation/Poster (Author's request): Oral presentation
Other authors and affiliations: Adriano Amaricci (SISSA), Massimo Capone (SISSA), Michele Fabrizio (SISSA)

We studied the metal-insulator Mott transition realized at quarter filling in a two-band Hubbard model. Using a combination of theoretical tools, such as Gutzwiller and dynamical mean-field theory methods, we constructed the phase-diagram of the model as a function of the bandwidth ratio. The phase-diagram is characterised by the presence, in the small-U regime, of a two-band metallic phase. When the bandwidth ratio is small, we find a continuous transition to a single band metal and eventually to a one-band Mott insulator by increasing the interaction strength. At larger bandwidth ratio a first order transition between the two-band metal to a one-band Mott insulator is observed. This transition is associated to the emergence of an anti-ferro orbital (AFO) ordering, which we explain by analysing the strong coupling Kugel-Khomskii model at mean field level.