A First-Principles Study of Two High-Pressure Modifications of Fe₃N

Most of the iron nitride compounds of the type Fe_xN are unstable at ambient pressure and temperature. However, Fe-rich nitrides can be synthesized in a high pressure confined environment. Using a large volume press and X-ray diffraction in combination with scanning electron microscopy techniques, two new high pressure phases of Fe₃N were observed with symmetries P6₃22 and P312 [1]. In this work, we perform a first-principles study based on density functional theory (DFT) within the general gradient approximation (GGA) and the local density approximation (LDA), and report on the structural, electronic, and phase stability properties as a function of pressure of these two iron nitride modifications. The exploration and understanding of high-energy density nitride materials is important as many of them exhibit remarkable technological applications due to their hardness, superconductivity or mechanical traits.

[1] Serghiou et al., High Press. Res. 35, 28-36, (2015)
* MNV is also at the Helmholtz Zentrum-Potsdam, Deutsches GeoForschungsZentrum (GFZ)