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.