Influence of the electron-electron interaction on the cyclotron excitation in microstructured quasi-twodimensional electron systems in GaAs
Project management at the University of Würzburg:
In the last years novel information on the influence of the electron-electron-interaction on the cyclotron resonance of quasi-twodimensional electron systems in GaAs could be gained. In samples with relative small electron densities (about 1010 cm-2) it was possible for the first time to observe a splitting of the cyclotron resonance line shape that can be expected from the conduction band nonparabolicity and the electron spin. The experiments could be explained in the framework of a theoretical concept that bases on the coupling of the electrical dipole transitions between the Landau-levels by many-body effects. Due to a stronger coupling at higher electron densities the splitting scenario cannot be observed and a quantitative analyses is difficult. As one can deduce from the experiments at small densities, the coupling strength depends also on the system size. The coupling strength approaches its maximum value already if the system contains 100 electrons. Via techniques of lateral microstructuring it is possible to realize electron systems, so called quantum dots, that contain less than 100 electrons, i.e., through the spatial limitation it is in principle possible to influence the coupling strength of the cyclotron transitions. Within this project we pursue cyclotron resonance experiments of microstructured electron systems in AlGaAs-GaAs heterostructures. From the experiments we expect novel information on the influence of many-body effects on the cyclotron excitation in particular in the regime of high electron densities.
Projekt period: from 05.1996 to 05.1999
VW-Stiftung ,Granting date: 24.05.1996