Resonant Inelastic Light Scattering on GaAs-AlGaAs Quantum Dots

Abstract

We investigate theoretically and experimentally the resonant Raman scattering on modulation-doped, deep-etched GaAs-AlGaAs quantum dots. The observation of so called single-particle excitations (SPE) in electronic Raman scattering on GaAs-AlGaAs nanostructures has been a puzzle for a long time. Our experimental investigations show that these excitations occur under conditions of extreme resonance, when the frequency of the incoming laser photons are close to the fundamental bandgap of the structure. To get a deeper understanding of the character of the SPE, we present an intriguing comparison of Kohn-Sham calculations with results of an exact many-body treatment by numerical diagonalization. We demonstrate that even for six electrons per quantum dot, single-particle-like excitations can be expected. In particular, we concentrate on a microscopic picture and show how the excitations can be described by a superposition of Hartree-Fock states.