Superconducting and topological properties of CoX (X = As, Sb and Bi)*

Recent studies have revealed high transition temperature (T_c) topological superconductivity in FeSe-based superconductors in either monolayer or bulk form. Here we use first-principles approaches to demonstrate that the systems of CoX (X = As, Sb, and Bi) are not only isovalent to FeSe, but also adopt the same layered structure, thereby may serve as new promising platforms to realize high-T_c superconductivity. Our detailed band structure analyses further show that these systems are topologically nontrivial, and can be exploited for materialization of topological superconductivity. Moreover, all these layered CoX structures can be stabilized on SrTiO₃(001), which not only could enhance T_c, but also preserve the topological nature. These findings characterize CoX as appealing new systems to achieve high-T_c superconductivity and topological properties.