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Phys. Rev. B 72, 045340 (2005) [7 pages]

Role of Coulomb interactions in dark-bright magnetoexciton mixing in strained quantum wells

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Y. D. Jho1,3, F. V. Kyrychenko1, J. Kono2, X. Wei3, S. A. Crooker4, G. D. Sanders1, D. H. Reitze1, C. J. Stanton1, and G. S. Solomon5
1Department of Physics, University of Florida, Gainesville, Florida 32611, USA
2Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005, USA
3National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA
4National High Magnetic Field Laboratory, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
5Solid-State Laboratories, Stanford University, Stanford, California 94305, USA

Received 13 October 2004; revised 24 March 2005; published 19 July 2005

Coupled magnetoexciton states between allowed (“bright”) and forbidden (“dark”) transitions are found in absorption spectra of strained In0.2Ga0.8As∕GaAs quantum wells with increasing magnetic field up to 30 T. We find large (∼9 meV) energy splittings in the mixed states. The observed anticrossing behavior is independent of polarization, and sensitive only to the parity of the quantum confined states. Detailed experimental and theoretical investigations indicate that valence band complexity does not play a role. We find that the excitonic Coulomb interaction is a necessary condition for the anticrossing to occur, while the magnitude of the energy splitting correlates with strain. In addition, we determine the spin composition of the mixed states.

© 2005 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevB.72.045340
DOI:
10.1103/PhysRevB.72.045340
PACS:
78.20.Ls, 78.67.−n, 75.20.−g
 
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