Calculation of exchange integrals and electronic structure for manganese ferrite

Article

关键词: GENERALIZED-GRADIENT-APPROXIMATION;    TRANSITION-METAL OXIDES;    DENSITY-FUNCTIONAL THERMOCHEMISTRY;    SELF-INTERACTION CORRECTION;    MOTT INSULATORS;    BAND-STRUCTURE;    HARTREE-FOCK;    NIO;    PHOTOEMISSION;    ENERGY;   

DOI  :  10.1103/PhysRevB.66.184420

来源: SCIE

【 摘 要 】

The electrical and magnetic properties of manganese ferrite (MnFe2O4) are calculated with the density-functional theory (DFT) method for both normal and inverse spinel structures. The exchange functional is chosen to be a mixture of Becke exchange and Fock exchange with variable weight (w). The exchange integrals J(AB) (the exchange integral between the nearest-neighbor A and B sites) and J(BB) (the exchange integral between nearest-neighbor B sites) are calculated by substituting the total energies of different magnetic ground states into the Heisenberg model. The calculated value of J(AB) is in agreement with the experimental values measured by neutron diffraction and NMR. Also, the parameters U (Coulomb repulsion energy), Delta (charge-transfer energy), and E-G (band gap) are extracted from the density of states (DOS) and plotted versus w. Our calculated band gap shows that MnFe2O4 is a complex insulator, in contrast to previous local spin-density approximation and generalized gradient approximation calculations, which showed it to be half metallic.

【 授权许可】

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