6533b838fe1ef96bd12a500c

RESEARCH PRODUCT

Orbital-selective Mott transitions in two-band Hubbard models

Carsten KnechtKrunoslav PožgajčićKrunoslav PožgajčićPeter Van DongenN. Blümer

subject

Condensed Matter::Quantum GasesPhysicsQuantum phase transitionStrongly Correlated Electrons (cond-mat.str-el)Condensed matter physicsHubbard modelQuantum Monte CarloMonte Carlo methodFOS: Physical sciencesCondensed Matter PhysicsElectronic Optical and Magnetic MaterialsMott transitionCondensed Matter - Strongly Correlated Electronssymbols.namesakeSelf-energysymbolsCondensed Matter::Strongly Correlated ElectronsSpin-flipHamiltonian (quantum mechanics)

description

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.

https://doi.org/10.1016/j.jmmm.2006.10.525