Potential existence of anti-postperovskite iron nitride Fe4N

The equations of state for cubic anti-perovskite (APV) and hypothetic anti post-perovskite (APPV) forms of Fe4N obtained within DFT for the spin polarized and non-magnetic configurations, confirm the ferromagnetic ground state of APV-Fe4N and a non-magnetic one for APPV. The lower equilibrium volume for the latter favors pressure-enabled transition: APV→APPVAPV→APPV. Chemical bonding analysis accounting for Fe differentiation into three sublattices for APPV characterized by edge and corner sharing octahedra, leads to a reinforced Fe–N chemical bonding. This is argued to help triggering the pressure transformation. It is the first case of potential post-anti-perovskite nitride.

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