Novel collective excitation spectrum and lifetime of electrons in a tunneling semiconductor superlattice

Abstract

We present theoretical results for the effect of electron tunneling on the collective excitation spectrum and lifetime of electrons in a semiconductor superlattice. Using a tight-binding envelope function and taking account of the nearest-neighbor-layer overlap enables us to derive the dynamical dielectric tensor, the zero of which yields the peculiar dispersion relations. The quasiparticle lifetime of excited electrons is evaluated by using the plasmon-pole approximation and is shown to display novel behavior.