Far-infrared spectroscopy of Zn 1−x Mn x GeAs 2 single crystals: Plasma damping influence on plasmon – Phonon interaction

The interest in thorough description of Zn1–xMnxGeAs2 arises from its suitability for application in the field of non-linear optics. The room temperature far-infrared reflectivity spectra of single crystals Zn1–xMnxGeAs2, where 0 ≤ x ≤ 0.078, were measured in the spectral range from 80 cm−1 to 500 cm−1. The spectra were analyzed by fitting procedure using a dielectric function which includes interaction between a plasmon and two different phonons. The detected phonons are in excellent agreement with the theoretical predictions. The MnAs cluster phonons are detected, as well.