Effects of a miniband structure on coherent LO phonon-plasmon coupled modes in an (InAs)(1)/(GaAS)(30) strained-layer superlattice

摘要

We have investigated coherent LO phonon-plasmon coupled (LOPC) modes in an (InAs)(1)/(GaAs)(30) strained-layer superlattice (SL) with a miniband structure. By generating carriers in the miniband, the GaAs-like LOPC modes are observed. In spectrally resolved pump-probe measurements, it is found that the intensity of the lower branch (L-) of the LOPC mode is enhanced around the transition energies at the miniband critical points, the mini-Brillouin-zone center and edge. In addition. the decay time of the L- mode in the SL hardly depends on the detection energy. These properties of the LOPC mode will be discussed from the viewpoint of the effect of the miniband structure. (C) 2002 Elsevier Science B.V. All rights reserved. [References: 6]