Photoluminescence of p-Doped Quantum Wells with Strong Spin Splitting

H. Boukaria, P. Kossackia,b,c, M. Bertolinia, D. Ferranda, J. Ciberta,d, S. Tatarenkoa, J.A. Gajb, B. Deveaudc and V. Ciulinc aNanophysique et Semiconducteurs group, CEA-CNRS-Université J. Fourier Grenoble, Laboratoire de Spectrométrie Physique, B.P. 87, 38402 St Martin d'Hères cedex, France bInstitute of Experimental Physics, Warsaw University, Hoża 69, 00-681 Warszawa, Poland cInstitute of Quantum Electronics and Photonics, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland dLaboratoire de Spectrométrie Physique, B.P. 87, 38402 St Martin d'Hères cedex, France

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Received: 10 06 2004

Photoluminescence of p-type modulation doped (Cd,Mn)Te quantum wells is studied with carrier density up to 5×1011 cm-2 at various spin splittings. This splitting can be made larger than the characteristic energies of the system thanks to the giant Zeeman effect. At small spin splitting and regardless of the carrier density, the photoluminescence exhibits a single line, which corresponds to the charged exciton in the singlet state. Above a certain spin splitting, the charged exciton is destabilized in favor of the exciton at vanishing hole density, and in favor of a double line at higher carrier density. It is found here that the charged exciton destabilization energy hardly depends on the carrier density. The double line is found to be band-to-band like, with the same initial state - where the holes have the same spin orientation - and final states that differ by some excitation of the 2D hole gas. In addition, the spin splitting needed to fully polarize the hole gas is twice smaller than expected from the single particle image and gives a unique insight into many-body effects in the hole gas.

DOI: 10.12693/APhysPolA.106.299 PACS numbers: 71.35.-y, 71.55.Gs, 73.21.Fg, 75.30.Hx, 75.50.Pp