Coexistence of Superconductivity and Topology in Bulk‐Phase Transition Metal Nitrides XMoN 4 (X = Transition Metal Elements) at Ambient Pressure

ABSTRACT Topological superconductors (TSCs) provide an ideal platform for investigating fundamental quantum phenomena, including non‐Abelian anyons and quantum entanglement, positioning them as a key area of focus in contemporary condensed matter physics research. Besides the widely explored transition metal sulfides (TMSs), transition metal nitrides (TMNs) may exhibit exceptional superconducting properties and non‐trivial topological quantum numbers. Here, we report a first‐principles study of the XMoN 4 (X = transition metal elements) family and predict their superconducting and topological properties at ambient pressure. Through the first‐principles calculations, we identify 7 stable superconductors, and NbMoN 4 exhibits the highest value of 47 K. The nesting of the Fermi surfaces and the flat bands caused by the d‐orbitals of metal atoms result in a high density of states, enhancing the pairing of electrons and phonons, thus leading to high T c . We further study the topological properties and find that the stabilized compound HgMoN 4, whose T c is 35 K at ambient pressure, also exhibits surface states and a Z 2 index of (1, 001). Our work predicts a stable superconductor with topological properties under ambient pressure from a constructed family of TMNs, expanding the study of combining the topological properties and superconductivity in bulk‐phase materials.