Filling dependence of the Mott transition in the degenerate Hubbard model

E. Koch(1,2), O. Gunnarsson(1), and R.M. Martin(2)
(1) Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany (2) Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Il 61801

Describing the doped Fullerenes using a generalized Hubbard model, we study the Mott transition for different integer fillings of the t1u band. We use the opening of the energy-gap Eg as a criterion for the transition. Eg is calculated as a function of the on-site Coulomb interaction U using fixed-node diffusion Monte Carlo. We find that for systems with doping away from half-filling the Mott transitions occurs at smaller U than for the half-filled system. We give a simple model for the doping dependence of the Mott transition.

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Phys. Rev. B 60, 15714 (1999).

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