Photoluminescence of Charged Excitons in Fractional Quantum Hall Systems

Neutral and charged excitonic complexes formed in integral and fractional quantum Hall systems are discussed. They are bound states of a small number of charged quasiparticles (e.g., conduction electrons and valence holes, reversed-spin electrons and spin holes, Laughlin quasielectrons and quasiholes, composite fermions) that occur in an electron system under specific conditions (electron density, well width, electric and magnetic fields, etc.). The examples are interband neutral and charged excitons, "anyon excitons", spin waves, skyrmions, and "skyrmion excitons". Their possible decay processes include radiative recombination, experimentally observed in photoluminescence or far infrared emission, or spin transitions, important in the context of nuclear spin relaxation.