Influence of non-local interactions on the Mott metal-insulator transition.

We investigate how short- and long-ranged non-local Coulomb interactions influence the metal-insulator phase boundary of the half-filled Hubbard model on square lattices and honeycomb lattices. We find that generally, non-local interactions stabilize the Fermi-liquid regime and that the phase boundary behaves linearly with infinitesimal non-local interactions. We present an upper bound for the boundary's slope. For our investigations, we use a variational principle which maps extended Hubbard models to effective purely local Hubbard models. The mapping relies on Quantum Monte Carlo solutions of the the local Hubbard model.