Effects of interorbital hopping on orbital fluctuations and metal-insulator transitions: Extended linearized dynamical mean-field theory

Abstract

We study the effects of interorbital hopping on orbital fluctuations and Mott-Hubbard metal-insulator transition (MIT) in the two-orbital Hubbard model within the extended linearized dynamical mean-field theory. By mapping the model onto an effective model with different bandwidths through the canonical transformation, we find that at half-filling, the increases of the interorbital Coulomb interaction $U^{\prime }$ and the Hund's coupling $J$ drive the MIT, and the critical $J_c$ for MIT increases with the lift of the inter-orbital hopping integral $t_{ab}$. Meanwhile at quarter filling and in the strong correlation regime, the system without $t_{ab}$ exhibits MIT with the decreasing of $J$, and favors the orbital liquid ground state. However, the system transits from metal to insulator with the increasing of t${}_{ab}$, accompanied with the rising of the orbital order parameter. These results show the important role of the interorbital hopping in the orbital fluctuation and orbital ordering.

arXiv comment7 pages, 6 figures

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• Novel Mott Transitions in Non-Isotropic Two-Band Hubbard Model
• Multisite versus multiorbital Coulomb correlations studied within finite-temperature exact diagonalization dynamical mean-field theory
• Is the orbital-selective Mott phase stable against interorbital hopping?
• A General Mechanism for Orbital Selective Phase Transitions
• Non-Fermi-liquid phases in the two-band Hubbard model: Finite-temperature exact diagonalization study of Hund's rule coupling
• Analytical slave-spin mean-field approach to orbital selective Mott insulators
• Two-orbital Systems with Crystal Field Splitting and Interorbital Hopping
• Orbital Selective Mott Transition Induced by Orbitals with Distinct Noninteracting Densities of States
• Doublon-holon excitations split by Hund's rule coupling within the orbital-selective Mott phase
• Metal-insulator transition in half-filling two-orbital Hubbard model on triangular lattice
• A dynamical mean-field study of orbital-selective Mott phase enhanced by next-nearest neighbor hopping