Exploring high transition temperature topological superconductivity in (Li1−xCoxOH)CoSb superlattices

Abstract

Among the FeSe-based superconductors, (Li1−xFexOH)FeSe has been discovered as an air-stable superlattice structure harboring both high transition temperature (high-Tc) superconductivity and intriguing topological superconducting properties. Here, we use first-principles approaches to identify a chemically isovalent and structurally identical counterpart of (Li1−xFexOH)FeSe, namely, (Li1−xCoxOH)CoSb, which not only is an attractive candidate to harbor high-Tc superconductivity, but also exhibits two distinct features surrounding topology and magnetism. The rationale of this predictive design is based on the recent identification of CoSb as a layered high-Tc superconductor stabilized on SrTiO3. We first show that the superlattice structures of (Li1−xCoxOH)CoSb (x=0 or 0.25) are dynamically and thermodynamically stable. Next, we demonstrate that (Li1−xCoxOH)CoSb possesses superior superconducting properties to (Li1−xFexOH)FeSe, offering an appealing platform for realizing high-Tc superconductivity beyond the Cu- and Fe-based superconducting systems. More strikingly, we find that (LiOH)CoSb is already topologically nontrivial even without extrinsic doping in the spacer layers, thereby offering a cleaner and more ideal candidate system for realizing topological superconductivity. Furthermore, (Li1−xCoxOH)CoSb exhibits weaker elemental magnetic moments than (Li1−xFexOH)FeSe, which may provide a different angle for elucidating the microscopic mechanisms of superconductivity in these and related systems.

Source-reported materials — not catalogue approval

Similar papers