Electronic structure of a two-dimensional Ising superconductor

Ising superconductivity is a mechanism where the critical in-plane magnetic field (Hc∥) of a two-dimensional (2D) superconductor is significantly enhanced by spin-orbit coupling (SOC). This unique phenomenon offers considerable potential for the development of superconducting devices that can operate in magnetic environments, making it highly relevant for quantum technologies.
Recent transport studies suggest that 2D gallium (Ga) film is a strong candidate for exhibiting Ising superconductivity, with Hc∥ values notably exceeding the Pauli limit. Density Functional Theory (DFT) calculations have indicated that the superconductivity arises from electron-phonon interactions, dominated by the SOC-split hole pocket at the K point. Despite previous ARPES studies having identified a small hole pocket at the K point, the fine structure of the bands near this region remains unresolved.
Therefore, we propose a comprehensive study on the electronic structure of high-quality 2D gallium (Ga) films using the high-resolution ARPES at BL20-LOREA of ALBA. This study aims to resolve the fine electronic structures near the K point, where we expect to observe a pair of SOC-split bands - an essential feature for the formation of Ising superconductivity. The outcome of this study will not only provide compelling evidence that Ga films are Ising superconductors, but also guide the future design of quantum electronic and magnetic devices based on 2D superconducting materials.