Multi-band theory of superconductivity at the LaAlO${}_3$/SrTiO${}_3$ interface

Abstract

We present a multi-band model for superconductivity at the metallic interface between insulating oxides LaAlO${}_3$ and SrTiO${}_3$ (001). Using a self-consistent Bogoliubov-de Gennes theory, formulated with the realistic bands at the interface, we investigate the spin-singlet and spin-triplet pairings in intra-band and inter-band channels. We find that the Rashba and atomic spin-orbit interactions at the interface induce singlet pairing in the inter-band channel and triplet pairing in both the intra-band and inter-band channels when the pairing amplitude in the singlet intra-band channel is finite. The gate-voltage variation of superconductivity is resolved in different pairing channels, compared with experimental results and found to match quite well. Interestingly, an enhancement of the superconducting transition temperature by external in-plane magnetic field is found revealing the existence of a hidden superconducting state above the observed one. As the interface is known to possess high level of inhomogeneity, we explore the role of non-magnetic disorder incorporating thermal phase fluctuations by using a Monte-Carlo method. We show that even after the transition to the non-superconducting phase, driven by temperature or magnetic field, the interface possesses localized Cooper pairs whose signature was observed in previous experiments.

10 pages, 8 figures

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Cited by in corpus (11)

• Cross-band versus intra-band pairing in superconductors: signatures and consequences of the interplay
• Evolution of topological superconductivity by orbital selective confinement in oxide nanowires
• Correlated Non-Gaussian phase fluctuations in LaAlO${}_3$/SrTiO${}_3$ heterointerface
• Interplay between singlet and triplet pairings in multi-band two-dimensional oxide superconductors
• Spin-orbital polarization of Majorana edge states in oxides nanowires
• Anomalous transport near the Lifshitz transition at the LaAlO${}_3$/SrTiO${}_3$ interface
• Effect of oxygen vacancy on structural, electronic and magnetic properties of La-based oxide interfaces
• Effect of spin-orbit interaction on the vortex dynamics in LaAlO${}_3$/SrTiO${}_3$ interfaces near the superconducting transition
• Influence of structural disorder and Coulomb interactions in the superconductor-insulator transition applied to boron doped diamond
• Layer-dependent electronic structures and magnetic ground states of polar-polar $\mathrm{LaV}{\mathrm{O}}_3/KTa{\mathrm{O}}_3$ (001) heterostructures
• Pressure induced evolution of anisotropic superconductivity and Fermi surface nesting in a ternary boride