Magneto-optical absorption in a two-dimensional electron grid

Abstract

We have fabricated a two-dimensional (2D) electron grid in the high mobility GaAs/Al0.35Ga0.65As heterostructure and observed, in the magneto-optical absorption, new resonances and an anomalous dispersion, similar to that recently reported by Kern et al.1 in antidots in a high density InGaAs/AlInAs heterostructure. We have studied their dependencies on the 2D electron density and demonstrate their plasma origin. The anomaly in magnetic field dependence is explained by the mixing of cyclotron resonance and edge magnetoplasma modes in this 2D electron microstructure.