Tunable superconductivity and its origin at KTaO3 interfaces

Journal Article · 19 February 2023 · Nature Communications

DOI: https://doi.org/10.1038/s41467-023-36309-2 · OSTI ID:1957856

Liu, Changjiang ; Zhou, Xianjing ; Hong, Deshun; Fisher, Brandon; Zheng, Hong; Pearson, John; Jiang, Jidong Samuel ; Jin, Dafei ; Norman, Michael R. ; Bhattacharya, Anand

Abstract What causes Cooper pairs to form in unconventional superconductors is often elusive because experimental signatures that connect to a specific pairing mechanism are rare. Here, we observe distinct dependences of the superconducting transition temperature T _c on carrier density n _2D for electron gases formed at KTaO ₃ (111), (001) and (110) interfaces. For the (111) interface, a remarkable linear dependence of T _c on n _2D is observed over a range of nearly one order of magnitude. Further, our study of the dependence of superconductivity on gate electric fields reveals the role of the interface in mediating superconductivity. We find that the extreme sensitivity of superconductivity to crystallographic orientation can be explained by pairing via inter-orbital interactions induced by an inversion-breaking transverse optical phonon and quantum confinement. This mechanism is also consistent with the dependence of T _c on n _2D . Our study may shed light on the pairing mechanism in other superconducting quantum paraelectrics.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE; USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division (MSE)
• Grant/Contract Number: AC02-06CH11357
• OSTI ID: 1957856
• Journal Information: Nature Communications, Journal Name: Nature Communications Journal Issue: 1 Vol. 14; ISSN 2041-1723
• Publisher: Nature Publishing GroupCopyright Statement
• Country of Publication: United Kingdom
• Language: English