Ab initio lattice dynamics of MnO

0332783 - ÚFM 2010 RIV GB eng J - Journal Article
Legut, Dominik - Wdowik, U.
Ab initio lattice dynamics of MnO.
Journal of Physics-Condensed Matter. Roč. 21, č. 27 (2009), Art. N. 275402. ISSN 0953-8984. E-ISSN 1361-648X
Institutional research plan: CEZ:AV0Z20410507
Keywords : lattice dynamics * MnO * ab initio
Subject RIV: BM - Solid Matter Physics ; Magnetism
Impact factor: 1.964, year: 2009

Vibrational dynamics of the MnO lattice has been studied using density functional theory combined with the direct method. Ab initio calculated Hellmann–Feynman forces were used to obtain density of states and the dispersion relations of phonons in the MnO crystal. Corrections for the local Coulomb interactions were applied. The Hubbard energies were varied from 1 to 7.9 eV. Increased Hubbard terms give a significant increase in the on-site force constants of cations, while the force constants on anions are affected indirectly. The density of phonon states and the dispersion curves are shifted to higher frequencies with the increasing Hubbard energies. The on-site Coulomb interactions influence mainly the optical phonon vibrations. The higher Hubbard terms lower the mean-squared vibrations of both cations and anions. The lattice contribution to the heat capacity experiences mall changes upon variation of Coulomb repulsion. Results of the calculations are compared to the existing experimental data.
Permanent Link: http://hdl.handle.net/11104/0177925