Extension of the Quasicubic Model to Ternary Chalcopyrite Crystals

A simple theoretical model is proposed to explain the recently observed valence-band structure of CdSn${\mathrm{P}}_2$ and similar chalcopyrite crystals. The valence bands of a chalcopyrite crystal are regarded as equivalent to those of a strained version of its binary analog. This model predicts the signs and magnitudes of the valence-band splittings observed in CdSn${\mathrm{P}}_2$ and ZnSi${\mathrm{As}}_2$. We show further that the quasicubic model explains quantitatively the unusual polarization dependences previously reported.