Anisotropic superconductivity at KTaO3(111) interfaces

Ethan G Arnault; Athby H Al-Tawhid; Salva Salmani-Rezaie; David A Muller; Divine P Kumah; Mohammad S Bahramy; Gleb Finkelstein; Kaveh Ahadi

doi:10.1126/sciadv.adf1414

Anisotropic superconductivity at KTaO₃(111) interfaces

Sci Adv. 2023 Feb 15;9(7):eadf1414. doi: 10.1126/sciadv.adf1414. Epub 2023 Feb 15.

Authors

Ethan G Arnault¹, Athby H Al-Tawhid², Salva Salmani-Rezaie^{3

4}, David A Muller^{3

4}, Divine P Kumah⁵, Mohammad S Bahramy⁶, Gleb Finkelstein¹, Kaveh Ahadi^{2

5}

Affiliations

¹ Department of Physics, Duke University, Durham, 27701 NC, USA.
² Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27265, USA.
³ School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853, USA.
⁴ Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, NY 14853, USA.
⁵ Department of Physics, North Carolina State University, Raleigh, NC 27695, USA.
⁶ Department of Physics and Astronomy, The University of Manchester, Oxford Road, Manchester M13 9PL, UK.

Abstract

A two-dimensional, anisotropic superconductivity was recently found at the KTaO₃(111) interfaces. The nature of the anisotropic superconducting transition remains a subject of debate. To investigate the origins of the observed behavior, we grew epitaxial KTaO₃(111)-based heterostructures. We show that the superconductivity is robust against the in-plane magnetic field and violates the Pauli limit. We also show that the Cooper pairs are more resilient when the bias is along [11[Formula: see text]] (I ∥ [11[Formula: see text]]) and the magnetic field is along [1[Formula: see text]0] (B ∥ [1[Formula: see text]0]). We discuss the anisotropic nature of superconductivity in the context of electronic structure, orbital character, and spin texture at the KTaO₃(111) interfaces. The results point to future opportunities to enhance superconducting transition temperatures and critical fields in crystalline, two-dimensional superconductors with strong spin-orbit coupling.