Dimer Mott Insulator in an Oxide Heterostructure

Abstract

We study the problem of designing an artificial Mott insulator in a correlated oxide heterostructure. We consider the extreme limit of quantum confinement based on ionic discontinuity doping, and argue that a unique dimer Mott insulator can be achieved for the case of a single SrO layer in a GdTiO${}_3$ matrix. In the dimer Mott insulator, electrons are localized not to individual atoms but to bonding orbitals on molecular dimers formed across a bilayer of two TiO${}_2$ planes, and is analogous to the Mott insulating state of Hubbard ladders, studied in the 1990s. We verify the existence of the dimer Mott insulator through both ab initio and model Hamiltonian studies, and find for reasonable values of Hubbard $U$ that it is stable and ferromagnetic with a clear bonding/anti-bonding splitting of order 0.65eV, and a significant smaller Mott gap whose size depends upon $U$. The combined effects of polar discontinuity, strong structural relaxation and electron correlations all contribute to the realization of this unique ground state.

5 pages, 4 figures

References in corpus (6)

• Wannier90: A Tool for Obtaining Maximally-Localised Wannier Functions
• Surprises on the Way from 1D to 2D Quantum Magnets: the Novel Ladder Materials
• Why Some Interfaces Cannot be Sharp
• Wien2wannier: From linearized augmented plane waves to maximally localized Wannier functions
• Electrostatic carrier doping of GdTiO3/SrTiO3 interfaces
• Toward an artificial Mott insulator: Correlations in confined, high-density electron liquids in SrTiO3

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• Orbital and spin order in oxide two-dimensional electron gases
• Understanding the role of exchange and correlations in complex oxides under strain and oxide heterostructures
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