Pressure modulates the phase stability and physical properties of zinc nitride iodine

Abstract

To explore new stable phases in metal nitride halides, the structural, electronic and optical properties, and chemical bonding characteristics of Zn₂NI under pressure were studied on the basis of crystal structure predicting evolution and density function calculations. Three new high-pressure phases of Zn₂NI were revealed: Pna2₁ and Pnma-II phases with NZn₄ tetrahedrons, and P6₃/mmc phase with NZn₆ polyhedrons above 6, 23, and 94 GPa, respectively. The calculated electronic structures of all the phases of Zn₂NI under pressure indicated that they are all semiconductors except P6₃/mmc phase. Therefore, pressure can simulated Zn₂NI a transition from a semiconductor to a metal. The optical properties (e.g., absorption coefficient, dielectric function) of these high-pressure phases were also discussed.