Spin-Orbit Splitting in CdS: Se Single Crystals

Abstract

Calculated values of the spin-orbit splittings from previously measured valence-band splittings in single crystals of CdS and CdSe at liquid-helium temperatures are 0.065 and 0.418 eV, $\stackrel{\mathrm{̇}}{\mathrm{r}}$espectively. In this investigation, spin-orbit splittings have been determined for solid solutions of CdS: Se single crystals from transmission measurements on thin platelets at 4.2°K. The single-crystal platelets of approximately 1 μ thickness were grown from the vapor phase. Measurements which have been made on seven intermediate compositions indicate that the spin-orbit splittings vary in an approximately linear manner with composition. The average deviation from linearity is approximately 10% greater than the experimental uncertainties. It is believed that slight deviations from linearity may be due to (1) the deviation of CdS from the ideal $\frac{c}{a}$ ratio in the wurtzite structure and (2) the greater contribution of ionic binding in CdS.