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Orbital-selective Mott transitions in two-band Hubbard models

N. Blümer·C. Knecht·K. Pozgajcic·P. G. J. van Dongen
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Abstract

The anisotropic two-orbital Hubbard model is investigated at low temperatures using high-precision quantum Monte Carlo (QMC) simulations within dynamical mean-field theory (DMFT). We demonstrate that two distinct orbital-selective Mott transitions (OSMTs) occur for a bandwidth ratio of 2 even without spin-flip contributions to the Hund exchange, and we quantify numerical errors in earlier QMC data which had obscured the second transition. The limit of small inter-orbital coupling is introduced via a new generalized Hamiltonian and studied using QMC and Potthoff's self-energy functional method, yielding insight into the nature of the OSMTs and the non-Fermi-liquid OSM phase and opening the possibility for a new quantum-critical point.

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N. Blümer, C. Knecht, K. Pozgajcic, P. G. J. van Dongen. 2006-09-29. Orbital-selective Mott transitions in two-band Hubbard models. https://doi.org/10.1016/j.jmmm.2006.10.525

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