Superconductivity in higher titanium oxides

Abstract

Recent renewal of the highest transition temperature in a conventional superconductor of the sulfer hydride attracts much attention to exploring simple compounds with the lighter elements, situated in unconventional conditions. We report the discovery of superconductivity in simple oxides of Ti4O7 and g-Ti3O5 in a thin-film form having deliberately tuned epitaxial structures and off-stoichiometry. These higher titanium oxides join in a class of simple-oxide superconductors, and g-Ti3O5 now holds the highest superconducting transition temperature of 7.1 kelvin among them. The mechanism behind the superconductivity is discussed on the basis of electrical measurements and theoretical predictions. We conclude that superconductivity arises from unstabilized bipolaronic insulating states.

25 pages, 4 figures in main text, 14 pages, 11 figures in supplemental information

References in corpus (4)

• Conventional superconductivity at 203 K at high pressures
• Quantum Hydrogen-Bond Symmetrization and High-Temperature Superconductivity in Hydrogen Sulfide
• Enhanced Superconductivity in TiO Epitaxial Thin Films
• Superconductivity in SnO: a Nonmagnetic Analog to Fe-based Superconductors?

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• Superconducting Phase of $\mathrm{T}{\mathrm{i}}_{\mathrm{x}}{\mathrm{O}}_{\mathrm{y}}$ Thin Films Grown by Molecular Beam Epitaxy
• Epitaxial stabilization of an orthorhombic Mg-Ti-O superconductor
• Introduction to High-Temperature Superconductivity for Solid State Chemists
• In-situ scattering studies of superconducting vacancy-ordered monoclinic TiO thin films