First-principles insights into the high-pressure stability and electronic characteristics of molybdenum nitride

Molybdenum nitride, renowned for its exceptional physical and chemical properties, has garnered extensive attention and research interest. In this study, we employed first-principles calculations and the CALYPSO structure prediction method to conduct a comprehensive analysis of the crystal structures and electronic properties of molybdenum nitride (Mo_xN_1−x) under high pressure. We discovered two novel high-pressure phases: Imm2-MoN₃ and Cmmm-MoN₄, and confirmed their stability through the analysis of elastic constants and phonon dispersion curves. Notably, the MoN₄ phase, with its high Vickers hardness of 36.9 GPa, demonstrates potential as a hard material. The results of this study have broadened the range of known high-pressure phases of molybdenum nitride, providing the groundwork for future theoretical and experimental researches.