Short-length-scale conductivity enhancement in a superlattice

Abstract

We have used far-infrared absorption to probe the optical conductivity of metallic GaAs:Si sheets imbedded in GaAs by molecular-beam epitaxy. An enhancement of the conductivity is observed at short length scales which we attribute to localization and Coulomb-interaction effects. However, the spectra do not appear to be quantitatively described by existing theories for long length scales.