Inhomogeneous multi-carrier superconductivity at LaXO3/SrTiO3 (X=Al or Ti) oxide interfaces

Abstract

Several experiments reveal the inhomogeneous character of the superconducting state that occurs when the carrier density of the two-dimensional electron gas formed at the LaXO3/SrTiO3 (X=Al or Ti) interface is tuned above a threshold value by means of gating. Re-analyzing previous measurements, that highlight the presence of two kinds of carriers, with low and high mobility, we shall provide a description of multi-carrier magneto-transport in an inhomogeneous two-dimensional electron gas, gaining insight into the properties of the physics of the systems under investigation. We shall then show that the measured resistance, superfluid density, and tunneling spectra result from the percolative connection of superconducting "puddles" with randomly distributed critical temperatures, embedded in a weakly localizing metallic matrix. We shall also show that this scenario is consistent with the characteristics of the superconductor-to-metal transition driven by a magnetic field. A multi-carrier description of the superconducting state, within a weak-coupling BCS-like model, will be finally discussed.

arXiv comment12 pages 10 figures

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Cited by in corpus (10)

• Emergent phenomena in multicomponent superconductivity: an introduction to the focus issue
• Phase separation from electron confinement at oxide interfaces
• Non-linear $IV$ characteristics in two-dimensional superconductors: Berezinskii-Kosterlitz-Thouless physics vs inhomogeneity
• Percolative nature of the dc paraconductivity in the cuprate superconductors
• Gate-tunable hallmarks of unconventional superconductivity in non-centrosymmetric nanowires
• Pseudo-gap in tunneling spectra as a signature of inhomogeneous superconductivity in oxide interfaces
• Evidence for Superconducting Phase Coherence in the Metallic/Insulating Regime of the LaAlO3-SrTiO3 Interface Electron System
• Flux-flow instability across Berezinskii Kosterlitz Thouless phase transition in KTaO${}_3$ (111) based superconductor
• Density inhomogeneities and Rashba spin-orbit coupling interplay in oxide interfaces
• Superfluid response of two-dimensional filamentary superconductors