Novel finite-q plasmons in p-type GaAs/AlxGa1−xAs quantum wells

We present a calculation of collective plasmon excitations in p-type GaAs/AlGaAs quantum wells, which is based on the random phase approximation and takes, within the 4×4 k·p model, band-structure effects exactly into account. We predict that the strong dependence of the subband wave functions on the in-plane wave vector, which does not exist in n-type quantum wells, leads to the existence of a novel, additional inter-subband plasmon at finite wave vectors and to a strong coupling of the intra- and the inter-subband plasmons, even in symmetric wells.