Tunable critical field in Rashba superconductor thin-films

TL;DR

This paper investigates how Rashba spin-orbit coupling influences the critical magnetic field in thin-film superconductors, revealing controllable parameters for enhancing superconductivity beyond traditional limits.

Contribution

It provides a quantitative analysis of the magnetic phase diagram in finite-size Rashba superconductors, highlighting the effects of size, shape, and external parameters on the critical field.

Findings

Critical field can be increased beyond Pauli limit due to Rashba coupling.

Sample geometry and field direction significantly influence the critical field.

Finite size and shape anisotropy affect the superconducting phase diagram.

Abstract

The upper critical field in type II superconductors is limited by the Pauli paramagnetic limit. In superconductors with strong Rashba spin-orbit coupling this limit can be overcome by forming a helical state. Here we quantitatively study the magnetic field-temperature phase diagram of finite-size superconductors with Rashba spin-orbit coupling. We discuss the effect of finite size and shape anisotropy. We demonstrate that the critical field is controllable by intrinsic parameters such as spin-orbit coupling strength and tunable parameters such as sample geometry and applied field direction. Our study opens new avenues for the design of superconducting spin-valves.