Structural, elastic and electronic properties of Cr2N: A first-principles study

The superior hardness of hexagonal Cr2N makes it potential applications as hard film. In this paper, first principles calculations are firstly made to investigate the structural, elastic and electronic properties of Cr2N. The site preferences of N in Cr2N crystal are evaluated by the formation energies of various configurations. The theoretical elastic properties of Cr2N are obtained and show close relation with the N occupation. The N occupations of 1a and 2d sites enable Cr2N the enhanced stability and increased elastic modulus and shear modulus. The N occupation at 2c sites shows a softening effect indicated by decreased shear modulus. The analysis on the density of states clarifies the variations of the stability and elastic properties of Cr2N.