Many-body effects on intersubband transitions in semiconductor quantum-well structures

Many-body effects on intersubband excitations in modulation-doped semiconductor quantum-well structures are calculated by solving numerically the Bethe-Salpeter equation for the corresponding polarization function. Depolarization and excitonic effects cause large changes in the transition energies. In particular, the excitonic binding tends to cancel the corrections due to exchange self-energies. Very good agreement between theoretical results and light scattering experiments is shown. The same formulation also applies to the interpretation of infrared optical absorption spectra.