Band Structure of CdIn 2 S 4 by Heine-Abarenkov Model Potential Method

Energy bands in the spinel-type semiconductor CdIn 2 S 4 are calculated by using the Heine-Abarenkov model potential method. About 500 plane waves are used to obtain convergent results for this crystal which has 64 valence electrons in the unit cell. Semiconductor-like band structure is obtained with 0.75 eV direct gap at \(\varGamma\). It is found that two types of indirect transition \(\varLambda_{3}{\rightarrow}\varGamma_{1},\varSigma_{4}{\rightarrow}\varGamma_{1}\) can occur just below this energy. Atomic characters of the bands at \(\varGamma\) near the gap are examined by calculating the average charge densities inside the atomic spheres from the obtained pseudo-wave-functions. It is seen that the p-levels of all the constituent atoms contribute to the valence bands near the gap.