Lattice density-functional theory applied to the three-dimensional Hubbard model

Abstract A density functional theory of lattice fermion models has been developed using the single-particle density matrix γ ij as basic variable. The interaction-energy functional W ( γ ) of the repulsive Hubbard model derives from exact dimer results, scaling properties of W ( γ ) and known limits. Lattice density-functional theory is applied to the three-dimensional Hubbard model. Results for the ground-state energy and charge-excitation gap of the simple-cubic lattice are presented and discussed as a function of U / t and band filling.