Controlling the Superconducting Transition by Rotation of an Inversion Symmetry-Breaking Axis

TL;DR

This paper demonstrates that rotating the inversion symmetry-breaking axis in a Rashba spin-orbit coupled hybrid structure can effectively control the superconducting transition temperature, offering a novel tuning mechanism.

Contribution

It introduces a new method to tune $T_c$ by axis rotation, involving the conversion of singlet pairs into odd-frequency correlations in a hybrid superconductor.

Findings

Superconducting $T_c$ can be tuned by rotating the inversion symmetry-breaking axis.

Conversion of singlet pairs into odd-frequency pairs occurs, affecting superconductivity.

The method provides a different approach compared to magnetic hybrid systems.

Abstract

We consider a hybrid structure where a material with Rashba-like spin-orbit coupling is proximity coupled to a conventional superconductor. We find that the superconducting critical temperature $T_c$ can be tuned by rotating the vector $\boldsymbol{n}$ characterizing the axis of broken inversion symmetry. This is explained by a leakage of $s$-wave singlet Cooper pairs out of the superconducting region, and by conversion of $s$-wave singlets into other types of correlations, among these $s$-wave odd-frequency pairs robust to impurity scattering. These results demonstrate a conceptually different way of tuning $T_c$ compared to the previously studied variation of $T_c$ in magnetic hybrids.