Nitrogen-doping driven topological transition, Lifshitz transition, and superconducting dome in orthorhombic α−Mo2C

Abstract

Experimental studies have reported that nitrogen (N)-doped orthorhombic α−Mo2C exhibits a significant enhancement in its superconducting transition temperature (Tc). To elucidate the underlying mechanisms, we conducted a systematic first-principles investigation of N-doped α−Mo2C, focusing on its structural stability, electronic structure, phonon dynamics, and superconductivity. The results show that the superconductivity originates from the electron-phonon coupling (EPC) between Mo−4d orbital electrons and low-frequency vibrational modes of Mo atoms. As the N content increases, the Tc exhibits a dome-shaped variation, well-consistent with experimental observations. Notably, varying the N-doping concentration drives a Lifshitz transition and a trivial-nontrivial-trivial topological evolution, as confirmed by Wannier-based Z2 invariants. These findings provide important insights into the superconductivity and topology in N-doped α−Mo2C, and offer valuable guidance for the design of high-performance superconducting and topological quantum materials.

Source-reported materials — not catalogue approval

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