MAGNETOOPTICAL STUDIES OF LATERALLY MODULATED NANOSTRUCTURES GROWN ONGAAS VICINAL SUBSTRATES

We report on cyclotron resonance measurements of laterally modulated t wo-dimensional electron systems grown on GaAs vicinal substrates. In a heterojunction modulated by a fractional AlAs layer, an anomalous cyc lotron-intersubband coupling is observed which is due to the lateral p otential modulation. In lateral-surface superlattices, deviations from a 2D behaviour in the position and in the linewidth of the cyclotron resonance are observed. It is proposed that this is the result of the lifting of Landau degeneracy by the superlattice potential, i.e., the formation of Landau bands. Possible contributions of many-body effects are discussed. In particular, additional absorption features are obse rved above the cyclotron resonance which we tentitatively ascribe to m agnetoplasmons at q=2 pi/a (a=lateral periodicity).