Uniaxial-stress determination of the symmetry of excitons associated with the miniband dispersion in (Ga,In)As-GaAs superlattices

This paper describes both experimental and theoretical demonstrations of an unexpected symmetry of the carrier envelope functions associated with resonant states in superlattices. The experiments reveal a mixing between the first light-hole (confined state) and the second heavy-hole (unconfined state) produced by application of a uniaxial stress in crossed configuration with the growth axis of a (Ga,In)As-GaAs superlattice. The theoretical aspects of the physics are addressed via both envelope function and tight-binding calculations.