Abstract
The authors develop a semi-classical theory of the intra-sub-band longitudinal electronic excitations in a quasi-(1+1)-dimensional semiconductor superlattice. By taking account of the frequency dependence of epsilon s( omega ), they find the coupled intra-sub-band plasmon-optical phonon bands. A quasi-(1+1)-dimensional semiconductor superlattice with a complex unit cell is also investigated; two possible plasmons are found. Finally, excitations in an isolated pair of one-dimensional quantum well wires are compared with those in the pair of two-dimensional electron gas layers.