Exciton Fine Structure via Envelope-Hole Coupling in Cubic ZnSe

Abstract

For the first time there is experimental evidence for a distinct fine structure in the exciton spectrum of cubic semiconductors caused by envelope-hole coupling. As an example, we present measurements of the $2P$ exciton in cubic ZnSe by two-photon absorption. The highly resolved threefold energy splitting into $P_{\frac{1}{2}}$, $P_{\frac{3}{2}}$, and $P_{\frac{5}{2}}$ states is explained within a spherical model. We determine the spherical effective-mass parameter $\mu$ and give an upper limit for the cubic parameter $\delta$.