FAR-INFRARED SPECTROSCOPY OF HG1-XMNXS ALLOYS

The far-infrared reflectivity spectra of Hg1-xMnxS (x = 0.02, 0.05, 0. 10, 0.20, 0.25, and 0.33) alloys were measured in the 30 to 500 cm(-1) spectral range at different temperatures and analyzed using a numeric al fitting procedure based on the plasmon-phonon interaction model. Th e three active modes at about 125, 189, and 305 cm(-1) are clearly obs erved. These modes were assigned as two-phonon resonant mode, zone cen ter phonon mode, and disorder-activated mode, respectively. It was sho wn that phonons in Hg1-xMnxS alloys (for Mn concentrations x less than or equal to 0.33) exhibit one-mode behavior.