Superconductivity in two-dimensional systems with unconventional Rashba bands

Abstract

In two-dimensional systems with Rashba spin-orbit coupling, it is well known that superconductivity can exhibit mixed spin-singlet and spin-triplet parity, with the d vector of spin-triplet pairing aligning parallel to the g vector of Rashba spin-orbit coupling. In this work, we propose a model to describe a two-dimensional system with unconventional Rashba bands and investigate its superconducting properties. We demonstrate that the d vector of spin-triplet pairing can be either parallel or perpendicular to the g vector of Rashba spin-orbit coupling, depending on the nature of the pairing interaction. We also propose a junction setup to identify the predominant pairing in such two similar pairing channels. Additionally, our model predicts the emergence of a subleading spin-singlet chiral p-wave topological superconducting state. Significantly, we find that such unconventional Rashba bands and superconducting pairings can be realized on the surface of certain superconducting topological materials, such as trigonal layered PtBi2.

Source-reported materials — not catalogue approval

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