EXCITON LUMINESCENCE IN THE QUANTUM HALL AND ELECTRON-SOLID REGIMES

Optical studies in the regime of the quantum Hall effect (QHE) reveal complex behavior related to the strongly interacting 2D electron syste m. In the following we review our recent investigations of exciton lum inescence in high-mobility GaAs electron systems. Several novel phenom ena are observed, including additional exciton peaks at high magnetic fields, intensity variations and energy shifts coincident with the qua ntum Hall effect, strongly suppressed recombination at nu = 1 and nu = 1/3, and peak splitting in the electron solid regime. The experiments were made using picosecond time-resolved PL measurements, dilution re frigerator temperatures (T > 0.05 K), and high magnetic fields (B less -than-or-equal-to 20 T).