Novel effects produced on a two dimensional electron gas by introducing InAs dots in the plane of the quantum well

We show that the presence of InAs dots embedded in a host GaAs quantum well containing a two-dimensional electron gas dramatically modifies the cyclotron resonance (CR). Far-infrared CR measurements show two modes with different dispersions with applied magnetic field B. The lower-frequency mode, with a sub-linear dependence on B, is identified as a CR at low B, developing into a skipping orbit around the dot perimeters at higher B. This has not been previously observed for a system with randomly distributed scatterers. The higher-frequency mode is identified as a magnetoplasmon localised by the confining effect of the arrays of repulsive potentials due to the dots in the well.