We have investigated the far-infrared response of quantum dots in modulation doped GaAs heterostructures. We observe modes at frequencies below the center-of-mass Kohn mode. Comparison with Hartree-random-phase-approximation calculations show that these modes arise from the flattened potential in our field-effect confined quantum dots. They reflect pronounced relative motion of the charge density with respect to the center of mass.
|Fræðitímarit||Physical Review B - Condensed Matter and Materials Physics|
|Útgáfustaða||Útgefið - 9 apr. 2001|