First-principles investigation on the high-pressure phase transitions and elastic constants of chromium nitrides

We performed first-principles calculations on the structural and electronic properties of chromium nitrides under high pressure. Based on crystal structure predictions, we identified several novel chromium nitrogen compounds and pressure-induced phase transitions in the Cr-N system from ambient pressure to 200 GPa. The dynamic stable compounds-CrN2, CrN6, and Cr2N3-are studied through both electronic and phononic calculations. This work provides a theoretical basis for the phase transition of Cr-N compounds under different pressures, points out the direction of future research on Cr-N systems, and may stimulate the synthesis of superhard and high energy density materials in the future.