Phonon-mediated superconductivity in : A first-principles study
Phys. Rev. B 113, 045116 – Published 9 January, 2026
DOI: https://doi.org/10.1103/sm9n-8qr1
Abstract
The recently discovered cobalt oxychalcogenide superconductor has attracted great attention due to its interesting properties, such as superconductivity, quasi-two-dimensionality, low carrier concentration, and very high upper critical field [J. Cheng et al., J. Am. Chem. Soc. 146, 5908 (2024)]. Nevertheless, the underlying superconducting mechanism of remains unclear and needs further theoretical clarification. In this work, we have systematically investigated the electronic structures, lattice dynamics, and superconducting properties of by performing first-principles calculations. Our computational results suggest that the superconductivity in originates from the strong electron-phonon coupling rather than the electronic correlation of Co electrons. The calculated superconducting transition temperature of 5.7 K agrees quite well with the experimental value, indicating that the superconducting pairing in belongs to the conventional Bardeen-Cooper-Schrieffer (BCS) type. Additionally, we find that the spin-orbital coupling (SOC) effect can induce unique spin textures for the bands around the Fermi level, which may explain the experimentally observed high upper critical field and its anisotropy along the in-plane and out-of-plane directions. Inspired by the results of , we also predict the bilayer heterostructure as a two-dimensional (2D) superconductor with the superconducting of 5.1 K. Our identification on the nature of superconductivity in and prediction on the superconductor call for future experimental verifications.
