First-principles study on the elastic and electronic properties of hexagonal ε-Fe3N

Using first-principles GGA+U calculations, we systematically studied the electronic structure, mechanical properties and Debye temperature (θD) of the hexagonal ε-Fe3N. The structural and elastic properties of ε-Fe3N were well described by considering the Fe 3d on-site Coulomb energy. The bulk modulus, shear modulus, Young’s modulus, and Poisson’s ratio determined by GGA+U method are 191.5 GPa, 79.3 GPa, 209.0 GPa and 0.32, respectively. They are in better agreement with the experimental values compared with GGA. ε-Fe3N exhibits virtually isotropic properties in compression and slightly anisotropic in shear. The modest in-plane elastic anisotropy in a–c plane of ε-Fe3N was also revealed. The Debye temperature of ε-Fe3N was calculated from the elastic moduli and sound velocities. It is indicated that the θD value obtained by GGA+U method is in better agreement with experimental data.

► First-principles GGA+U calculations are employed to study the ε-Fe3N.
► Elastic properties were well described by considering the Fe 3d on-site Coulomb energy.
► ε-Fe3N exhibits completely isotropic properties in compression and slightly anisotropic in shear.
► The modest in-plane elastic anisotropy in a–c plane of ε-Fe3N was revealed.