Density Functional Theory Study Of Transition Metals Doped In N Under High Pressure

InN has excellent electrical properties such as small electron mass,high electron mobility,and high saturated electron drift rate,which has a wide application prospect in the field of microelectronic devices.Doping and pressure are effective means to control material properties.Based on density functional theory,GGA+U method was used in CASTEP to analyze the structural phase transition and related performance changes of perfect InN and Ti In₂₃N₂₄,Fe In₂₃N₂₄,Ni In₂₃N₂₄,and（Cr,In）N doped system under high pressure,which had important guiding significance for the experiment.The research showed that the perfect InN with wurtzite or zinc-blende structure would transform to rocksalt structure under the hydrostatic pressure of 0 GPa-20 GPa.Just like the perfect InN,transition metals doped InN also undergo the phase transformation from B_M4 and B_M3 structure to B_M1 structure.Besides,the dopant of Fe increased the phase transition pressure when the dopant of Ti,Cr,and Ni decreased the phase transition pressure.The electronic structures of perfect InN and MIn₂₃N₂₄（M=Ti,Cr,Fe,Ni）were calculated by the method of GGA+U.In these structures,perfect InN,Cr In₂₃N₂₄with B_M3 structure and Ti In₂₃N₂₄ with B_M4 were semiconductor.Before the phase transformation,the increasing pressure led to a decrease of interatomic distance,so the band gap of the perfect InN increased with the increasing pressure.However,when the pressure increased,the band gap of Cr₁In₂₃N₂₄ system increased firstly and then decreases,it was because of a combination of the compressed atomic spacing and the presence of free electrons.Furthermore,the band gap of Ti In₂₃N₂₄ also increased gradually under hydrostatic pressure of 0 GPa-20 GPa.Perfect InN was nonmagnetic,but after the dopant of transition metals,spin polarization phenomenon occurred in（Cr,In）N、Fe In₂₃N₂₄、Ni In₂₃N₂₄ systems.The magnetism of the doped systems mainly came from transition metals,and with the pressure increasing,the magnetic moment of transition metals tended to decrease,the Curie temperature of Cr₂In₂₂N₂₄ decreased slowly,but it was still much higher than room temperature,and had stable ferromagnetism.The dielectric function,absorption,reflection,and energy loss function of perfect InN and doped system under high pressure were calculated by the sane method.The results showed that the optical spectra of perfect InN and doped system were blue shift with the pressure increasing,and the energy loss was reduced in the low energy region.There are 48 figures,12 tables and 107 references in the paper.