First-principles study of magnetism in spinel MnO2

Article

关键词: DENSITY-FUNCTIONAL THEORY;    TOTAL-ENERGY CALCULATIONS;    WAVE BASIS-SET;    FINITE-TEMPERATURE;    PHASE-TRANSITION;    DYNAMICS;    LAMBDA-MNO2;    LIMN2O4;    SYSTEMS;    K2NIF4;   

DOI  :  10.1103/PhysRevB.67.134404

来源: SCIE

【 摘 要 】

First-principles electronic structure methods have been used to calculate the ground state, transition temperature, and thermodynamic properties of magnetic excitations in spinel MnO2. The magnetic interactions are mapped onto a Heisenberg model whose exchange interactions are fitted to results of first-principles calculations of different spin configurations. The thermodynamics are calculated using Monte Carlo methods. The Heisenberg model gives an extremely accurate representation of the true first-principles magnetic energies. We find a critical temperature and Weiss constant significantly larger than experimental results and believe the error to come from the local spin density approximation. We predict a new magnetic ground state different from that proposed previously, but consistent with experimental data.

【 授权许可】

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