Regensburg 2010 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 19: CE: Metal-Insulator Transition 2
TT 19.6: Vortrag
Mittwoch, 24. März 2010, 10:45–11:00, H18
First principles study of the electronic structure and phonon properties on double-layer manganites — •Omar De la Peña-Seaman, Rolf Heid, and Klaus-Peter Bohnen — Karlsruher Institut für Technologie (KIT), Institut für Festkörperphysik, Germany
We have studied the electronic and lattice dynamical properties of the tetragonal double-layer manganite system La2−2xSr1+2xMn2O7 (x=0.4) within the framework of density functional perturbation theory, using a mixed-basis pseudopotential method and the virtual crystal approximation for modeling the alloy. The system has been investigated for non-magnetic and ferromagnetic phases. The performance of LDA and GGA exchange-correlation functionals on the properties under study was analyzed. We have used the experimental lattice constants, optimizing the internal structural parameters for each magnetic phase (non-magnetic and ferromagnetic). The electronic band structure as well as individual contributions to the density of states are discussed. The calculated phonon dispersion in [ξ00] and [ξξ0] high-symmetry directions for different magnetic phases are compared between them and with experimental data available in the literature. In addition, an analysis of the most representative phonon modes is performed, and the electron-phonon couplings discussed in detail.