Dispersion of the birefringence in zinc diphosphide crystals

Optical phonon behaviors in ZnGeP2 single crystals from temperature dependent far-infrared reflectance spectra

“…In ZnGeP 2 allowed vibrations are distributed into following symmetries: A 1 + 2A 2 + 3B 1 + 4B 2 + 7E, B 2 and E modes are allowed to be infrared active [11]. B 2 modes can be observed employing the radiation polarized parallel to the c-axis, the radiation polarized normal to the c-axis used to detect E modes.…”