After half a century of debate, superconductivity in doped SrTiO_3 has come to the fore again with the discovery of interfacial superconductivity in the LaAlO_3/SrTiO_3 heterostructures. While these interfaces share the interesting properties of bulk SrTiO_3 , quantum confinement generates a complex band structure involving bands with different orbital symmetries whose occupancy is tunable by electrostating doping. Multigap superconductivity has been predicted to emerge in LaAlO_3/SrTiO_3 at large doping, with a Bose-Einstein condensation character at the Lifshtiz transition. In this article, we report on the measurement of the upper critical magnetic field Hc2 of superconducting (110)-oriented LaAlO3 /SrTiO3 heterostructures and evidence a two-gap superconducting regime at high doping. Our results are quantitatively explained by a theoretical model based on the formation of an unconventional s±-wave superconducting state with a repulsive coupling between the two condensates.
Two-gap s± -wave superconductivity at an oxide interface / Singh, G.; Venditti, G.; Saiz, G.; Herranz, G.; Sánchez, F.; Jouan, A.; Feuillet-Palma, C.; Lesueur, J.; Grilli, M.; Caprara, S.; Bergeal, N.. - In: PHYSICAL REVIEW. B. - ISSN 2469-9950. - 105:6(2022). [10.1103/PhysRevB.105.064512]
Two-gap s± -wave superconductivity at an oxide interface
Venditti, G.Co-primo
;Grilli, M.;Caprara, S.
Penultimo
;
2022
Abstract
After half a century of debate, superconductivity in doped SrTiO_3 has come to the fore again with the discovery of interfacial superconductivity in the LaAlO_3/SrTiO_3 heterostructures. While these interfaces share the interesting properties of bulk SrTiO_3 , quantum confinement generates a complex band structure involving bands with different orbital symmetries whose occupancy is tunable by electrostating doping. Multigap superconductivity has been predicted to emerge in LaAlO_3/SrTiO_3 at large doping, with a Bose-Einstein condensation character at the Lifshtiz transition. In this article, we report on the measurement of the upper critical magnetic field Hc2 of superconducting (110)-oriented LaAlO3 /SrTiO3 heterostructures and evidence a two-gap superconducting regime at high doping. Our results are quantitatively explained by a theoretical model based on the formation of an unconventional s±-wave superconducting state with a repulsive coupling between the two condensates.File | Dimensione | Formato | |
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