FAR-INFRARED RESPONSE OF QUANTUM DOTS - FILLING FACTOR DEPENDENCE AT HIGH MAGNETIC-FIELDS

In recent experiments by Bollweg et al. (Phys. Rev. Lett., 76 (1996) 2 774) a novel feature was observed in the far-infrared absorption spect ra of quantum dots: the resonance frequency of the low-lying omega(-) mode exhibits small oscillations in dependence on the magnetic field. By calculating the self-consistent far-infrared response of electrons in quantum dots, we can give an explanation for this behavior. For hig h magnetic fields, the occupation of electron states in the quantum do t can be related to a filling factor defined for the density in the ce nter of the dot. We trace back the oscillations in the omega(-) mode t o an oscillatory filling factor dependence of the radial extension of the electron density.