Abstract
The collective charge-density excitations, the intra- and intersubband plasmons, and their manifestation in far-infrared transmission spectroscopy are studied for coupled quantum wells. We calculate self-consistently the ground state in the Hartree approximation and the density response in the random-phase approximation. We investigate the plasmons in symmetric coupled quantum wells in dependence on the coupling between the two wells and study the effects of deviation from the spatial symmetry. It is shown that the intersubband coupling forms a hybrid-type mode spectrum. The strong hybridization of the collective intrasubband motion with the lowest-frequency intersubband transition presses one branch in the single-particle intrasubband continuum and the higher-frequency intersubband modes form doublets. The optical transmission spectra of these samples with a grating coupler above the electron system show a strong exchange of oscillator strength between the modes. © 1996 The American Physical Society.
- Received 11 April 1996
DOI:https://doi.org/10.1103/PhysRevB.54.11436
©1996 American Physical Society