Two-orbital Systems with Crystal Field Splitting and Interorbital Hopping

Abstract

The nondegenerate two-orbital Hubbard model is studied within the dynamic mean-field theory to reveal the influence of two important factors, i.e. crystal field splitting and interorbital hopping, on orbital selective Mott transition (OSMT) and realistic compound Ca${}_{2-x}$Sr${}_x$RuO${}_4$. A distinctive feature of the optical conductivity of the two nondegenerate bands is found in OSMT phase, where the metallic character of the wide band is indicated by a nonzero Drude peak, while the insulating narrow band has its Drude peak drop to zero in the mean time. We also find that the OSMT regime expands profoundly with the increase of interorbital hopping integrals. On the contrary, it is shown that large and negative level splitting of the two orbitals diminishes the OSMT regime completely. Applying the present findings to compound Ca${}_{2-x}$Sr${}_x$RuO${}_4$, we demonstrate that in the doping region from $x=0.2$ to 2.0, the negative level splitting is unfavorable to the OSMT phase.

7 pages with 5 figures

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Cited by in corpus (11)

• Is the orbital-selective Mott phase stable against interorbital hopping?
• A General Mechanism for Orbital Selective Phase Transitions
• Analytical slave-spin mean-field approach to orbital selective Mott insulators
• Assessing the orbital selective Mott transition with variational wave functions
• Competition of crystal field splitting and Hund's rule coupling in two-orbital magnetic metal-insulator transitions
• Can Orbital-Selective Néel Transitions Survive Strong Nonlocal Electronic Correlations?
• Doublon-holon excitations split by Hund's rule coupling within the orbital-selective Mott phase
• Orbital Selective Mott Transition Induced by Orbitals with Distinct Noninteracting Densities of States
• Orbital Selective Phase Transition
• A dynamical mean-field study of orbital-selective Mott phase enhanced by next-nearest neighbor hopping
• Quantitative determination of the orbital-selective Mott transition and quantum entanglement in the orbital-selective Mott phase