Mass Reversal Effect in the Split Indirect Exciton of Ge

Abstract

Experimental and theoretical evidence is reported of hybridization effects leading to strong nonparabolicity in the $E-K$ dispersion curves of the Ge anisotropy-split excitons. The measured density of states indicates substantial deviation from ideal-gas behavior even at a few kelvins. A splitting of 1.01 ± 0.03 meV is measured.