Many-body effects in the electromodulation spectra of modulation-doped quantum wells: Theory and experiment

We have performed a theoretical (first-principles) and experimental (contactless electroreflectance) investigation of the temperature dependence (17<T<351 K) of the electric-field-modulated interband transitions in a pseudomorphic ${\mathrm{Ga}}_{0.81}$${\mathrm{Al}}_{0.19}$As/${\mathrm{In}}_{0.20}$${\mathrm{Ga}}_{0.80}$As/GaAs modulation-doped quantum well that contains a two-dimensional electron gas. We find that many-body effects are a factor at all temperatures although they are most pronounced for T<=152 K. Because of the derivativelike nature of our approach, both theoretical and experimental, the weak Fermi-edge transition is still visible up to at least 152 K, as a complement to the results of previous theoretical and experimental investigations.