Quantum size and correlation effects in the double excitation spectrum of a quantum dot

This work deals with the double excitation of electronic states of semicond uctor quantum dots as induced by photoabsorption. The prime focus is put on the manifestation of quantum size and correlation effects in the two-parti cle excited spectrum. The photon field is treated within the dipole approxi mation whereas the Green function method is employed to describe the excite d two-particle spectrum. Our numerical simulations demonstrate that the dim ensionality of the dot as well as the amount of inter-electronic correlatio n have a marked effect on the dot's excitation spectrum. The underlying phy sics of these effects can be understood from the functional structure of th e inter-electronic interaction in a many-electron system as well as from th e characteristic change of the electronic states when varying the size of t he dot from the strong localization regime to an extended structure. (C) 20 01 Elsevier Science B.V. All rights reserved.