Photoemission study of the electronic structure of a (GaAs)2/(AlAs)2superlattice

We report results from an angle-resolved photoemission study of the electronic structure of the short-period superlattice (GaAs${)}_2$/(AlAs${)}_2$. These results support the first-principles linear-muffin-tin-orbital-method calculation of Gopalan et al. In particular, a 0.5-eV band gap caused by the reduced periodicity in the [001] growth direction is clearly seen at a binding energy (relative to the valence-band maximum) of 5.3 eV.