Optical absorption studies of pyrite-type RuS₂ RuSe₂ and RuTe₂ single crystals

Far-Inflated optical characterization of pyrite - type RuS₂ RuSe₂ and RuTe₂ have been studied by absorption measurements. We measured these three types of pyrite single crystals in spectra ranging from 100 - 700 cm^-1 at temperature among 80 - 300 K. Those vibration modes of these crystals are clearly shown temperature dependent behavior in far-infrared range. The main peaks ofphonon modes of RuSz are near around 244 · 341 · 366 · 401 and 416 cm^-1 at 80 K that is shown in its reflectance spectra. There are three main phonon peaks clearly showed 207 · 257 and 297 cm^-1 for RuSe₂ single crystal. However RuTe₂ crystal has only clearly shown a main phonon peak near around 247 cm^-1 at 80 K in the reflectance spectra for its highly metallic behavior. This metallic behavior of RuTe₂ is also shown in photo reflectance measurements. All of these phonon modes have 2 - 4 cm^-1 shift in among 80 - 300 K. The phonon modes, carrier concentration, mobility, effective mass as well as their dielectric behavior of these pyrite-type crystals will go further study.