Competing Correlated Insulators in multi-orbital systems coupled to phonons

Abstract

We study the interplay between electron-electron interaction and a Jahn-Teller phonon coupling in a two-orbital Hubbard model. We demonstrate that the e-ph interaction coexists with the Mott localization driven by the Hubbard repulsion U, but it competes with the Hund's coupling J. This interplay leads to two spectacularly different Mott insulators, a standard high-spin Mott insulator with frozen phonons which is stable when the Hund's coupling prevails, and a low-spin Mott-bipolaronic insulator favoured by phonons, where the characteristic features of Mott insulators and bipolarons coexist. The two phases are separated by a sharp boundary along which an intriguing intermediate solution emerges as a kind of compromise between the two solutions.

6 pages, 4 figures

References in corpus (20)

• Strong electronic correlations from Hund's coupling
• Modeling the Unconventional Superconducting Properties of Expanded A${}_3$C${}_{60}$ Fullerides
• Efficient DMFT-simulation of the Holstein-Hubbard Model
• Interplay between electron-phonon and Coulomb interactions in cuprates
• Phase diagram for the one-dimensional Hubbard-Holstein model: A density-matrix renormalization group study
• Electron-phonon interaction and antiferromagnetic correlations
• Superconductivity, charge-density waves, antiferromagnetism, and phase separation in the Hubbard-Holstein model
• Competition between antiferromagnetic and charge order in the Hubbard-Holstein model
• Synergistic Polaron Formation in the Hubbard-Holstein Model at Small Doping
• Excitation spectra and spin gap of the half-filled Holstein-Hubbard model
• EDIpack: A parallel exact diagonalization package for quantum impurity problems
• Interaction-resistant metals in multicomponent Fermi systems
• Local Kekulé distortion turns twisted bilayer graphene into topological Mott insulators and superconductors
• Charge instabilities and electron-phonon interaction in the Hubbard-Holstein model
• Localization of strongly correlated electrons as Jahn-Teller polarons in manganites
• Downfolding electron-phonon Hamiltonians from ab-initio calculations: application to K${}_3$Picene
• Gutzwiller scheme for electrons and phonons: the half-filled Hubbard-Holstein model
• Effects of the electron-phonon coupling near and within the insulating Mott phase
• Isotope effects in the Hubbard-Holstein model within dynamical mean-field theory
• Local vs non-local correlation effects in interacting quantum spin Hall insulators