Berlin 2018 – wissenschaftliches Programm
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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 12: Multiferroics and magnetoelectrics II (joint session MA/KFM)
KFM 12.6: Vortrag
Mittwoch, 14. März 2018, 11:00–11:15, EB 202
A theoretical study on the electronic and magnetic excitation spectra of BiFeO3 by dynamical mean-field theory — •Souvik Paul1,2, Diana Iusan1, Patrik Thunström1, Yaroslav Kvashnin1, Johan Hellsvik1,3, Manuel Pereiro1, Anna Delin1,3, Biplab Sanyal1, and Olle Eriksson1 — 1Department of Physics and Astronomy, Uppsala University, Sweden — 2Institute of Theoretical Physics and Astrophysics, Christian-Albrechts-Universität zu Kiel, Germany — 3Department of Materials and Nano Physics, KTH Royal Institute of Technology, Sweden
Using local density approximation plus dynamical mean-field theory (LDA+DMFT), we have computed the electronic and magnetic excitation spectra of one of the popular multiferroic BiFeO3. Our calculated eletronic spectra match very well with the experimental (hard X-ray photoelectron spectroscopy and resonant photoelectron spectroscopy for the Fe 3d states) spectra as compared to the commonly used LDA+U method, which fails drastically to produce the general features of the experimental spectra. This indicates the importance of correctly including the dynamical correlation among the Fe 3d orbitals to reproduce the experimental spectroscopic data. The LDA+DMFT derived density of states (DOS) exhibit significant amount of Fe 3d states at the position of Bi lone-pairs, implying that the latter are not alone in the spectral scenario. This fact might modify our interpretation about the origin of ferroelectric polarization in this material. Our magnetic excitation spectra computed from the LDA+DMFT results conform well with the inelastic neutron scattering data.