OH)CoSb as A New Superlatticed Superconductor*

We study theoretically the superlattice material of (Li_0.8Co_0.2OH)CoSb as a new candidate superconductor, in which the superconducting layer CoSb has the same crystal structure as FeSe, but with stronger spin-orbit coupling (SOC). Through density functional theory calculations, we find that substitution of Li by Co in the spacing layer not only minimizes the lattice mismatch between the spacing and superconducting layers in the ab plane, but also helps to stabilize the overall structure of the system. Moreover, we have investigated the detailed nature of charge transfer and found that Co in the spacing layer can significantly enhance the interlayer charge transfer, which is essential for achieving superconductivity. The predicted system is not only likely to add a new member into the superconducting family, but may also offer new opportunities for realizing topological superconductivity because of the stronger SOC.