Magnetoluminescence and magnetoreflectance of theAexciton of CdS and CdSe

Magnetoluminescence and magnetoreflectance have been measured on the $A$ exciton of CdS and CdSe in magnetic fields up to 12 T. In the case of CdS, we get the following results: For $\overrightarrow{\mathrm{H}}\parallel \overrightarrow{\mathrm{c}}$ the luminescence line at 2.553 eV, attributed to the ${\Gamma }_6$ triplet state splits into two components giving a $g$ factor $|g_{h\parallel }+g_{e\parallel }|=3.02\mathrm{}\pm 0.10$. From the directly measured difference between ${\sigma }^{-}$ and ${\sigma }^{+}$ polarized light the $g$ factor of the ${\Gamma }_5$ singlet state is determined as $g_{h\parallel }-g_{e\parallel }=-0.56\mathrm{}\pm 0.05$, and thus we derive the electron and hole $g$ values $g_{e\parallel }=+1.79\mathrm{}\pm 0.10$ and $g_{h\parallel }=+1.23\mathrm{}\pm 0.10$. In luminescence with $\overrightarrow{\mathrm{E}}\perp \overrightarrow{\mathrm{c}}$ polarization and $\overrightarrow{\mathrm{H}}\parallel \overrightarrow{\mathrm{c}}$ a narrow line emerges with increasing magnetic field at energies below the ${\Gamma }_5$ luminescence peak. The additional line is attributed to the low-energy component of the ${\Gamma }_6$ triplet state. The most prominent feature of the magnetoreflectance spectra is the appearance of an additional reflectance structure below the main reflectance minimum for $\overrightarrow{\mathrm{E}}\perp \overrightarrow{\mathrm{c}}$ and $\overrightarrow{\mathrm{H}}\perp \overrightarrow{\mathrm{c}}$. This structure is attributed to the triplet state becoming observable due to magnetic-field-induced mixing between the ${\Gamma }_5$ and ${\Gamma }_6$ states of the $A$ exciton. From the diamagnetic shift of the ${\Gamma }_6$ state for $\overrightarrow{\mathrm{H}}\parallel \overrightarrow{\mathrm{c}}$ we derive ${\mu }_x=0.16\mathrm{}$, while