Two-gap s± -wave superconductivity at an oxide interface
Journal article, 2022
After half a century of debate, superconductivity in doped SrTiO3 has come to the fore again with the discovery of interfacial superconductivity in the LaAlO3 /SrTiO3 heterostructures. While these interfaces share the interesting properties of bulk SrTiO3, 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 LaAlO3 /SrTiO3 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.
Author
Gyanendra Singh
Institute of Material Science of Barcelona (ICMAB)
Université Paris PSL
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics
G. Venditti
Sapienza University of Rome
Istituto Dei Sistemi Complessi, Rome
G. Saiz
Université Paris PSL
G. Herranz
Institute of Material Science of Barcelona (ICMAB)
F. Sánchez
Institute of Material Science of Barcelona (ICMAB)
A. Jouan
Université Paris PSL
C. Feuillet-Palma
Université Paris PSL
J. Lesueur
Université Paris PSL
M. Grilli
Sapienza University of Rome
Istituto Dei Sistemi Complessi, Rome
S. Caprara
Istituto Dei Sistemi Complessi, Rome
Sapienza University of Rome
N. Bergeal
Université Paris PSL
Physical Review B
24699950 (ISSN) 24699969 (eISSN)
Vol. 105 6 064512Subject Categories
Other Physics Topics
Theoretical Chemistry
Condensed Matter Physics
DOI
10.1103/PhysRevB.105.064512