Effect of magnetoexciton correlations on the coherent emission of semiconductors

Journal Article · Thu Dec 17 04:00:00 EST 1998 · Physical Review B. Condensed Matter and Materials Physics

OSTI ID:773741

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

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1. LBNL Library

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.

• Research Organization: Lawrence Berkeley National Lab., CA (US)
• Sponsoring Organization: USDOE Director, Office of Science (US)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 773741
• Report Number(s): LBNL--42868
• Journal Information: Physical Review B. Condensed Matter and Materials Physics, Journal Name: Physical Review B. Condensed Matter and Materials Physics Journal Issue: 7 Vol. 60
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COHERENT RADIATION
EMISSION
EXCITONS
GALLIUM ARSENIDES
HARTREE-FOCK METHOD
MAGNETIC FIELDS
PARTICLE INTERACTIONS
SEMICONDUCTOR MATERIALS
SENSITIVITY