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arXiv · 1706.09644

First-order metal-insulator transitions in the extended Hubbard model due to self-consistent screening of the effective interaction

M. Schüler·E. G. C. P. van Loon·M. I. Katsnelson·T. O. Wehling
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Abstract

While the Hubbard model is the standard model to study Mott metal-insulator transitions, it is still unclear to which extent it can describe metal-insulator transitions in real solids, where non-local Coulomb interactions are always present. By using a variational principle, we clarify this issue for short- and long-ranged non-local Coulomb interactions for half-filled systems on bipartite lattices. We find that repulsive non-local interactions generally stabilize the Fermi-liquid regime. The metal-insulator phase boundary is shifted to larger interaction strengths to leading order linearly with non-local interactions. Importantly, non-local interactions can raise the order of the metal-insulator transition. We present a detailed analysis of how the dimension and geometry of the lattice as well as the temperature determine the critical non-local interaction leading to a first-order transition: for systems in more than two dimensions with non-zero density of states at the Fermi energy the critical non-local interaction is arbitrarily small; otherwise it is finite.

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M. Schüler, E. G. C. P. van Loon, M. I. Katsnelson, T. O. Wehling. 2018-04-24. First-order metal-insulator transitions in the extended Hubbard model due to self-consistent screening of the effective interaction. https://doi.org/10.1103/physrevb.97.165135

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