Superfluid stiffness of a KTaO3-based two-dimensional electron gas

Abstract

After almost twenty years of intense work on the celebrated LaAlO3/SrTiO3 system, the recent discovery of a superconducting two-dimensional electron gases (2-DEG) in (111)-oriented KTaO3-based heterostructures injects new momentum to the field of oxides interfaces. However, while both interfaces share common properties, experiments also suggest important differences between the two systems. Here, we report gate tunable superconductivity in 2-DEGs generated at the surface of a (111)-oriented KTaO3 crystal by the simple sputtering of a thin Al layer. We use microwave transport to show that (111)-KTaO3 2-DEGs exhibit a node-less superconducting order parameter with a gap value significantly larger than expected within a simple BCS weak-coupling limit model. Consistent with the two-dimensional nature of superconductivity, we evidence a well-defined Berezinsky-Kosterlitz-Thouless type of transition, which was not reported on SrTiO3-based interfaces. Our finding offers innovative perspectives for fundamental science but also for device applications in a variety of fields such as spin-orbitronics and topological electronics.

References in corpus (7)

• Electric Field Control of the LaAlO${}_3$/SrTiO${}_3$ Interface Ground State
• Two-dimensional superconductivity at the surfaces of KTaO3 gated with ionic liquid
• Phase fluctuations in a strongly disordered s-wave superconductor close to the metal-insulator transition
• Universal Fabrication of Two-Dimensional Electron Systems in Functional Oxides
• Tunable superconductivity at the oxide-insulator/KTaO${}_3$ interface and its origin
• Band Structure and Spin-Orbital Texture of the (111)-KTaO3 Two-Dimensional Electron Gas
• Slowing down of vortex motion in thin NbN films near the superconductor-insulator transition

Cited by in corpus (22)

• Tunable superconductivity at the oxide-insulator/KTaO${}_3$ interface and its origin
• Spontaneous rotational symmetry breaking in KTaO${}_3$ heterointerface superconductors
• Orientation-dependent electron-phonon coupling in interfacial superconductors LaAlO3/KTaO3
• Generalized Rashba Electron-Phonon Coupling and Superconductivity in Strontium Titanate
• Coexistence of ferromagnetism and superconductivity at KTaO${}_3$ heterointerfaces
• Superconductivity at epitaxial LaTiO3-KTaO3 interfaces
• Flux-flow instability across Berezinskii Kosterlitz Thouless phase transition in KTaO${}_3$ (111) based superconductor
• Anisotropic Rashba coupling to polar modes in KTaO3
• Superconducting quantum oscillations and anomalous negative magnetoresistance in a honeycomb nanopatterned oxide interface superconductor
• Dense and single-phase KTaO${}_3$ ceramics obtained by spark plasma sintering
• Coexistence of high electron-mobility, unpaired spins, and superconductivity at high carrier density SrTiO${}_3$-based interfaces
• Universally enhanced superconductivity and coexisting ferroelectricity at oxide interfaces
• Strong phase coherence and vortex matter in a fractal system with proximity-induced superconductivity
• KTaO3(001) Preparation Methods in Vacuum: Effects on Surface Stoichiometry, Crystallography, and in-gap States
• Spin-dependent anisotropic electron-phonon coupling in KTaO${}_3$
• Spontaneous nonreciprocal transport in a gate-tunable ferromagnetic Rashba 2-dimensional electron gas
• Majorana edge modes in isolated wires
• Achieving superconductivity in infinite-layer nickelate thin films by aluminum sputtering deposition
• Orientation-dependent superconductivity and electronic structure of the rare-earth metal/KTaO3 interfaces
• Geometric Control of Pairing: Universal Scaling of Superconductivity at KTaO3 Interfaces
• Controlling Spin-Mixing Conductance in KTaO${}_3$ 2DEGs by Varying Argon-Ion Irradiation Time
• Superfluid response of two-dimensional filamentary superconductors