Spin-dependent photoluminescence at v = 1 filling factor

We perform high-resolution, polarized photoluminescence (PL) experiments on a high-mobility GaAs/AlGaAs single quantum well near v = 1. Upon entering the v = 1 quantum-Hall region the PL shows a remarkable polarization dependence. For RCP polarization the PL exhibits the usual reduction of the peak intensity, and a cusp in the spectral energy of the peak. For LCP polarization we observe unanticipated novel behavior: a major change in the PL line shape, and the development of two new peaks, one above and one below the main emission peak. This large asymmetry between RCP and LCP polarizations can be modeled by considering the initial spin-configuration prior to the recombination of the e-h pair. Among the models consistent with our observations are a "shake-up" process in which finite-momentum spin waves are generated in the electron system upon recombination in the LCP polarization.