AbstractWe investigate the possible electromagnetically induced collective excitation modes in a bilayer quasi‐two‐dimensional structure build from two adjacent parabolic quantum wells (PQW). We consider both charge and spin excitation modes within and beyond the random phase approximation method. To account for higher order effects we used exchange and correlation spin‐dependent local field correction factors. We analyzed intra‐ and inter‐subband excitations and provide analytic results for their excitation frequencies in the long wavelength limit. In particular, we analyze the spin polarization dependence of the lowest frequency spin density mode and show that its relevant frequency is in the hundred GHz region. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
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