Mott metal-insulator transition in the Doped Hubbard-Holstein model

Abstract

Motivated by the current interest in the understanding of the Mott insulators away from half filling, observed in many perovskite oxides, we study the Mott metal-insulator transition (MIT) in the doped Hubbard-Holstein model using the Hatree-Fock mean field theory. The Hubbard-Holstein model is the simplest model containing both the Coulomb and the electron-lattice interactions, which are important ingredients in the physics of the perovskite oxides. In contrast to the half-filled Hubbard model, which always results in a single phase (either metallic or insulating), our results show that away from half-filling, a mixed phase of metallic and insulating regions occur. As the dopant concentration is increased, the metallic part progressively grows in volume, until it exceeds the percolation threshold, leading to percolative conduction. This happens above a critical dopant concentration ${\delta }_c$, which, depending on the strength of the electron-lattice interaction, can be a significant fraction of unity. This means that the material could be insulating even for a substantial amount of doping, in contrast to the expectation that doped holes would destroy the insulating behavior of the half-filled Hubbard model. Our theory provides a framework for the understanding of the density-driven metal-insulator transition observed in many complex oxides.

References in corpus (3)

• First order Mott transition at zero temperature in two dimensions: Variational plaquette study
• Coulomb Interactions and Nanoscale Electronic Inhomogeneities in Manganites
• Phase separation in doped Mott insulators

Cited by in corpus (9)

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• Mott-Anderson Metal-Insulator Transitions from Entanglement
• Response of the lattice across the filling-controlled Mott metal-insulator transition of a rare earth titanate
• Two-component electronic phase separation in the doped Mott insulator Y${}_{1-x}$Ca${}_x$TiO${}_3$
• Emergent Magnetism at the 3$d$-5$d$ Interface: SrMnO${}_3/$SrIrO${}_3$
• Linear colossal magnetoresistance driven by magnetic textures in LaTiO3 thin films on SrTiO3
• Stability of the Antiferromagnetic State in the Electron Doped Iridates