LAUSR

Transition metal (TM) nitrides has been widely used in many scientific and technical areas because of their unique physical and mechanical properties. However, most of the well-known transition metal nitrides are nitrogen deficient. The reports on nitrogen-rich TM nitrides are rather scarce and sometimes even show discrepancy in their crystal structures. Herein, the microstructure, stability, electronic property, and hardness of nitrogen-rich molybdenum nitride MoN2 compound have been investigated systematically by using an unbiased structure search method crystal structure analysis by particle swarm optimization combined with first-principle calculations. Our study demonstrates a stable configuration orthorhombic Cmc21 (no. 36) for MoN2 crystal, which is even lower in energy than the experimental synthesized structure rhombohedral R3m-MoN2 at ambient pressure condition. The formation enthalpies with respect to the reactant Mo + N2, mechanical stabilities, and phonon dispersions further confirm the stabil...