Dispersion of Phonon Surface Polaritons in ZnGeP(2): Anisotropy and Temperature Impacts

Zinc germanium diphosphide (ZnGeP(2)) is an attractive and promising functional material for different devices of the nano- and optoelectronics. In this paper, dispersion of phonon surface polaritons (PSPs) in ZnGeP(2) has been studied in the 200–500-cm(−1) spectral range at 4 and 300 K. Dispersion of “real” and “virtual” PSPs were calculated for C-axis being normal and parallel to the surface. Anisotropy in ZnGeP(2) leads to the different numbers of PSP dispersion branches for different orientations of the sample. The temperature-dependent phonon contributions in the dielectric permittivity shift dispersion of the surface polaritons in ZnGeP(2) to the higher wavenumbers at 4 K. We have shown that experimental dispersion of PSP is in agreement with theory.