First-principles modeling of magnetic excitations in Mn-12

Article

关键词: AUGMENTED-WAVE METHOD;    MAGNETOCRYSTALLINE ANISOTROPY;    EXCHANGE INTERACTIONS;    ELECTRONIC-STRUCTURE;    MOLECULES;    SPECTRA;    ALLOYS;   

DOI  :  10.1103/PhysRevB.89.214422

来源: SCIE

【 摘 要 】

We have developed a fully microscopic theory of magnetic properties of the prototype molecular magnet Mn-12. First, the intramolecular magnetic properties have been studied by means of first-principles density functional based methods, with local correlation effects being taken into account within the local density approximation plus U (LDA + U) approach. Using the magnetic force theorem, we have calculated the interatomic isotropic and anisotropic exchange interactions and full tensors of single-ion anisotropy for each Mn ion. Dzyaloshinskii-Moriya (DM) interaction parameters turned out to be unusually large, reflecting a low symmetry of magnetic pairs in molecules, in comparison with bulk crystals. Based on these results we predict a distortion of ferrimagnetic ordering due to DM interactions. Further, we use an exact diagonalization approach allowing one to work with as large a Hilbert space dimension as 108 without any particular symmetry (the case of the constructed magnetic model). Based on the computational results for the excitation spectrum, we propose a distinct interpretation of the experimental inelastic neutron scattering spectra.

【 授权许可】

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