Many-body optical-edge singularity in absorption spectra of GaAs/AlxGa1−xAs modulation-doped quantum wells

Abstract

The optical-absorption spectra of GaAs/${\mathrm{Al}}_{\mathrm{x}}$ ${\mathrm{Ga}}_{1\mathrm{-}\mathrm{x}}$As modulation-doped quantum wells are calculated by extending the many-body theory of two-dimensional electron gases into quasi-two-dimensional situations. The calculated Fermi-edge singularity depends strongly on the quantum-well parameters such as finite well thickness and potential-barrier heights. These more realistic considerations bring the theory into a much better agreement with recent experiments.