Prediction of CoSb as a new layered superconductor

FeSe-based superconductors have been actively studied in the field of high temperature superconductivity due to their relatively simple structures and exotic superconducting phenomena. Bulk FeSe possesses a superconducting transition temperature (T_c) of ~8 K, while substantially enhanced T_c of ~65 K has been reported in one-unit-cell FeSe films on the SrTiO₃(001) substrate. To date, the underlying superconducting and enhancement mechanisms are still under active debate. Here we employ first-principles calculations to predict a new layered superconductor of CoSb, which is isovalent to, and shares the same planar crystal structure with the single-layer FeSe. The electronic structures of the two systems are also very similar. In contrast, the magnetic properties of CoSb are distinctly different from that of FeSe, thereby offering new opportunities for exploiting high-T_c superconductivity and the underlying pairing mechanisms.