Coupled plasmon–LO-phonon modes inGaxIn1−xAs heterostructures

The coupled plasmon–longitudinal-optical (LO)-phonon modes are calculated, within the random-phase approximation, for a two-dimensional electron gas imbedded in a polar semiconductor exhibiting two LO-phonon modes. Numerical results are given for the collective excitation spectrum and the energy-loss function and applied to ${\mathrm{Ga}}_{\mathrm{x}}$ ${\mathrm{In}}_{1\mathrm{-}\mathrm{x}}$As heterostructures.