Superconductivity in a Magnetic Rashba Semimetal EuAuBi

TL;DR

This paper reports the discovery of superconductivity in EuAuBi, a layered magnetic Rashba semimetal, revealing complex magnetic and surface effects, with implications for spin-orbit coupled superconducting states.

Contribution

It presents the first observation of superconductivity in EuAuBi and links it to Rashba spin-orbit coupling and magnetic ordering, supported by first-principles calculations.

Findings

Superconductivity appears at 2.2 K in EuAuBi.

The upper critical field Hc2 is highly anisotropic, up to 9.8 T.

Surface conditions influence the superconducting transition.

Abstract

We report the observation of superconductivity with multiple magnetic ordering and Rashba-type spin-orbit coupling in a layered polar semimetal EuAuBi. Magnetic transition is observed at 4 K, followed by a superconducting transition at 2.2 K, which is sensitive to the crystal surface conditions. The upper critical field Hc2 of 9.8 T for the out-of-plane field is three times higher than that for the in-plane field, which can be associated with the two-dimensional structure or the surface state. On the basis of first-principles calculations, it is found that the characteristic Hc2 possibly reflects the anisotropic modification of the Fermi surface by the effective combination of Rashba-type spin splitting and Zeeman spin splitting enhanced by Eu moments.