Effect of magnetoexciton correlations on the coherent emission of semiconductors
- Department of Physics, University of California at Berkeley, Berkeley, California 94720 (United States)
- John von Neumann-Institute for Computing (NIC), Forschungszentrum Juelich, 52425 Juelich (Germany)
Mean-field, Hartree-Fock theory has been successful in explaining many nonlinear optical experiments in semiconductors. But recently experiments have shown important cases where the mean-field theory (the semiconductor Bloch equations) fails. One such case is bulk GaAs in a strong magnetic field. Here the exciton-exciton interaction can be tuned by varying the magnetic field, providing an excellent method for studying the transition from a regime where mean-field theory is valid to a regime where exciton-exciton correlations must be taken into account. We perform ultrafast time-resolved four-wave mixing on bulk GaAs in a magnetic field, and compare our experimental results with theoretical calculations which go beyond Hartree-Fock theory. We find excellent qualitative agreement. Furthermore, because of the strong correlations that are present, GaAs in a magnetic field presents an excellent opportunity to study the exciton-exciton correlations themselves. We investigate the coherence of the exciton-exciton correlations as the temperature and free-carrier density are varied, and find a surprising sensitivity of the exciton-exciton correlation coherence to these parameters. {copyright} {ital 1999} {ital The American Physical Society}
- OSTI ID:
- 362693
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 60, Issue 7; Other Information: PBD: Aug 1999
- Country of Publication:
- United States
- Language:
- English
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