Collective excitation spectra of one-dimensional electron systems

Abstract

We calculate, within the random-phase approximation, the elementary excitation spectrum of quasi-one-dimensional electron systems as occurring, for example, in semiconductor microstructures. Using multisubband models, we derive and discuss the dispersion relations for both intrasubband and intersubband excitations and consider the mode-coupling effect between them. We show that the depolarization shift correction for the intersubband excitation could be very large, increasing the intersubband collective mode energy substantially above the single-particle intersubband separation, and, thus explaining a puzzling recent far-infrared spectroscopic experimental observation.