Effect of magnetoexciton correlations on the coherent emission of semiconductors

Journal Article · Sun Aug 01 04:00:00 EDT 1999 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.60.4731· OSTI ID:362693

Kner, P; Bar-Ad, S; Marquezini, M V; Chemla, D S ^[1]; Loevenich, R; Schaefer, W ^[2]

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1. Department of Physics, University of California at Berkeley, Berkeley, California 94720 (United States)
2. 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, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 7 Vol. 60; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CARRIER DENSITY
CORRELATIONS
EXCITONS
FREQUENCY MIXING
GALLIUM ARSENIDES
MAGNETO-OPTICAL EFFECTS
TIME RESOLUTION