Room temperature Mott metal-insulator transition in V2O3 compounds induced via strain-engineering

Abstract

Vanadium sesquioxide (V2O3) is an archetypal Mott insulator in which the atomic positions and electron correlations change as temperature, pressure or doping are varied giving rise to different structural, magnetic or electronic phase transitions. Remarkably, the isostructural Mott transition in Cr-doped V2O3 between paramagnetic metallic and insulating phase observed in bulk has been elusive in thin film compounds so far. Here, via continuous lattice deformations induced by heteroepitaxy we demonstrate a room temperature Mott metal-insulator transition in 1.5% Cr-doped and pure V2O3 thin films. By means of a controlled epitaxial strain, not only the structure but also the intrinsic electronic and optical properties of the thin films are stabilized at different intermediate states between the metallic and insulating phases, inaccessible in bulk materials. This leads to films with unique features such as a colossal change in room temperature resistivity (DR/R up to 100,000 %) and a broad range of optical constant values, as consequence of a strain-modulated bandgap. We propose a new phase diagram for pure and Cr-doped V2O3 thin films with the engineered in-plane lattice constant as a tuneable parameter. Our results demonstrate that controlling phase transitions in correlated systems by epitaxial strain offers a radical new approach to create the next generation of Mott devices.

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Cited by in corpus (10)

• Nanoscale self-organisation and metastable non-thermal metallicity in Mott insulators
• An efficient direct band-gap transition in germanium by three-dimensional strain
• Strong effects of uniaxial pressure and short-range correlations in Cr2Ge2Te6
• Mott materials: unsuccessful metals with a bright future
• On the origin of supertetragonality in BaTiO${}_3$
• Mott resistive switching initiated by topological defects
• Lattice contraction induced by resistive switching in chromium-doped V2O3: a hallmark of Mott physics
• Disentangling transport mechanisms in a correlated oxide by photoinduced charge injection
• Confinement-Induced Isosymmetric Metal-Insulator Transition in Ultrathin Epitaxial V2O3 Films
• Two-dimensional honeycomb-kagome V2O3: a robust room-temperature magnetic Chern insulator interfaced with graphene