Measurement and simulation of anisotropy in the infrared and Raman spectra of beta-FeSi2 single crystals.

Guizzetti G., Marabelli F., Patrini M., Pellegrino P., Pivac B., Miglio L., Meregalli V., Lange H., Henrion W., Tomm V.

Univ Pavia Ist Nazl Fis Mat Via Bassi 6 I-27100 Pavia Italy
Univ Pavia Dipartimento Fis A Volta I-27100 Pavia Italy
Rudjer Boskovic Inst Hr-10000 Zagreb Croatia
Univ Milan Ist Nazl Fis Mat I-20133 Milan Italy
Univ Milan Dipartimento Fis I-20133 Milan Italy
Mpi Fkf D-70506 Stuttgart 80 Germany
Hahn Meitner Inst Berlin Gmbh Abt Photovolta D-12489 Berlin Germany
Hahn Meitner Inst Berlin Gmbh Abt Solare Energet D-12489 Berlin Germany

In this paper we show that the orthorhombic phase of FeSi2 (stable at room temperature) displays a sizable anisotropy in the infrared spectra, with minor effects in the Raman data too. This fact is not trivial at all, since the crystal structure corresponds to a moderate distortion of the fluorite symmetry. Our analysis is carried out on small single crystals grown by flux transport, through polarization-resolved far-infrared reflectivity and Raman measurements. Their interpretation has been obtained by means of the simulated spectra with tight-binding molecular dynamics.

Physical Review B, 55 14290-14297, 1997.

Max-Planck Institut für Festkörperforschung;
Postfach 80 06 65   D-70506 Stuttgart