Dresden 2009 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
MM: Fachverband Metall- und Materialphysik
MM 35: Poster Session II
MM 35.3: Poster
Mittwoch, 25. März 2009, 16:30–18:30, P4
Raman study of FeSi under high pressures up to 35 GPa — •Ivan Jursic1, Dirk Menzel1, Joachim Schoenes1, and Klaus Doll2 — 1Technische Universität Braunschweig, Institut für Physik der Kondensierten Materie, 38106 Braunschweig, Germany — 2Max-Planck-Institut für Festkörperforschung, 70569 Stuttgart, Germany
Single crystals of FeSi were grown by tri-arc Czochralski technique. These crystals were investigated by Raman spectroscopy in a diamond anvil cell at pressures up to 35 GPa. The experiment was performed at room temperature.
FeSi crystallizes in the B20 structure, i.e. space group P213. Factor group analysis predicts 9 Raman active phonon modes for this structure. Measurements outside of the DAC allowed the assignment of the vibrations and showed electron-phonon coupling [1]. Only the strong modes could be observed inside the DAC, i.e. two E-mode vibrations at 180 cm−1 and 313 cm−1 as well as two T-mode vibrations at 195 cm−1 and 310 cm−1.
With increasing pressure the frequencies of the vibrations shift to higher values. The observed shift was compared to density functional theory calculations made within a single particle model. The experiment and theory agree reasonable well. There is a small kink observed in the experiment around 15 GPa which can’t be attributed to a structural phase transition and is discussed as electron-phonon coupling.
[1] A.-M. Racu et. al. Phys. Rev. B 76, 115103(2007)