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.