Evidence of Singlet-Triplet Crossing in Photoluminescence of Positively Charged Excitons in GaAs Quantum Wells

L. Bryja, A. Wójs, J. Jadczak, J. Misiewicz Institute of Physics, Wrocław University of Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland P. Płochocka, M. Potemski Grenoble High Magnetic Field Laboratory, CNRS, 25 av. Martyrs, F-38042 Grenoble, France D. Reuter and A. Wieck Lehrstuhl fur Festkörperphysik, Ruhr Universität, Universitätstrasse 150, 44780 Bochum, Germany

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Received: 7 06 2008;

Positively charged excitons in a two-dimensional hole gas in symmetric and asymmetric GaAs/Ga1-x Alx As quantum wells are studied in polarization-resolved photoluminescence experiments in high magnetic fields B (up to 23 T) and low temperatures (down to 300 mK). The experiments are accompanied by numerical calculations of a real structure. The whole family of trions (the singlet and a pair of triplets) are observed. The Coulomb energies crossing of singlet and triplet is found: hidden in symmetric and visible in asymmetric structures.

DOI: 10.12693/APhysPolA.114.1073 PACS numbers: 73.20.Mf, 71.35.Ji, 71.35.Pq, 78.20.Ls