RAMAN-SCATTERING FROM A 2-DIMENSIONAL ELECTRON-GAS IN A WEAKLY AND PERIODICALLY MODULATED MAGNETIC-FIELD

An analysis of light scattering from a two-dimensional electron gas (2 DEG) subject to a weak periodic magnetic modulation of strength B-m an d to a perpendicular uniform magnetic field B of arbitrary strength is presented. Raman spectra are calculated for (i) electron inter-Landau -level transitions, which result in a Raman shift similar to 2 omega(c ) and (ii) inter-landau-level collective electron excitations at a hyb ridized magnetoplasmon frequency and at a new low-frequency, intra-Lan dau-level plasmon mode induced by the modulation. The dependence of th e Raman cross sections on the strength of B and B-m, is assessed. The effect of a weak B-m, on the Raman spectrum is similar to that of a we ak electric modulation but the signals from the magnetically modulated 2DEG are much stronger. The combined effect of the electric and magne tic modulations is also considered. (C) 1998 Academic press Limited.