Plasmon and Magnetoplasmon excitation in two-dimensional electron space-charge layers on GaAs.
01 January 1986
The excitation of two-dimensional (2D) plasmons in Al(x)Ga (1-x)As-GaAs heterostructures has been investigated with far- infrared transmission spectroscopy. Grating couplers of high efficiency and samples of high mobility (mu ~~ 1.8x10(5)cm (2)/Vs) make it possible to study the 2D plasmon dispersion up to plasmon wave vectors q >~ 2x10(5)cm(-1). Thus we can test the theoretically predicted second order q-corrections to the dispersion due to nonlocal effects, finite thickness of the space-charge layer and correlations. In perpendicular magnetic fields a strong nonlocal interaction of the 2D magnetoplasmon resonance with harmonics of the cyclotron resonance n (.) omega (c) (n = 2,3,...) is observed. Excellent agreement is found with predictions of a classical nonlocal theory.