Enhanced Critical Field of Superconductivity at an Oxide Interface

TL;DR

This study demonstrates that superconductivity at LaMnO3/KTaO3(111) interfaces exhibits exceptional resilience to magnetic fields, likely due to spin-orbit coupling effects, with critical fields reaching 25 T and sensitivity to carrier density.

Contribution

The paper provides new insights into the robustness of superconductivity at oxide interfaces, highlighting the role of spin-orbit coupling in enhancing critical magnetic fields.

Findings

Superconductivity persists up to 25 T magnetic field.

Superconducting properties are highly sensitive to carrier density.

Spin-orbit coupling induces anomalous quasiparticles with minimal magnetic moments.

Abstract

The nature of superconductivity and its interplay with strong spin-orbit coupling at the KTaO3(111) interfaces remains a subject of debate. To address this problem, we grew epitaxial LaMnO3/KTaO3(111) heterostructures. We show that superconductivity is robust against the in-plane magnetic field, with the critical field of superconductivity reaching 25 T in optimally doped heterostructures. The superconducting order parameter is highly sensitive to carrier density. We argue that spin-orbit coupling drives the formation of anomalous quasiparticles with vanishing magnetic moment, providing the condensate significant immunity against magnetic fields beyond the Pauli paramagnetic limit. These results offer design opportunities for superconductors with extreme resilience against magnetic field.