Far-infrared optical constants of a selection of zincblende structure crystals at 300 K

The far-infrared amplitude and phase reflection spectra of six group III–V single crystal compounds (GaP, GaAs, GaSb, InP, InAs, and InSb) and two group II–VI single crystal compounds (CdTe and ZnSe) with the zincblende structure have been determined at room temperature in the region of their reststrahlen bands by reflection dispersive Fourier transform spectroscopy. The measured amplitude and phase reflection spectra and values of the optical constants calculated from them are presented. As an illustration of weak mode anharmonicity in these crystals, the imaginary part of the anharmonic self-energy of the infrared-active transverse optic mode of ZnSe at the centre of the Brillouin zone is calculated from its measured dielectric functions. Prominent features in the self-energy function in the region of the reststrahlen band are assigned as phonon combination bands with the aid of critical point phonon frequencies derived from an 11-parameter rigid-ion model.