Energy and recombination spectra of free and impurity-bound positive trions in high magnetic fields

Abstract

Recombination spectra of free and acceptor-bound positive trions in a quasi-two-dimensional hole gas are investigated by the combination of polarization-resolved photoluminescence and transport in high magnetic fields B and the realistic numerics. The whole family of free positive trions (the pair of bright and dark triplets in addition to the well-known singlet) is observed for the first time. Crossing of the singlet and triplet Coulomb energies is found at B ≈ 12 T . Slight decrease of all trion emission energies is observed at B = 14.2 T , coincident with the formation of a ν = 1 3 Laughlin hole liquid. For the acceptor-bound trions, weak inter-Landau-level shake-up transitions are identified and explained by the breaking of translational invariance.