R. Lovenich et al., THEORY OF COHERENTLY DRIVEN BIEXCITONS IN STRONG MAGNETIC-FIELDS, Physica status solidi. a, Applied research, 164(1), 1997, pp. 347-351
A new regime at low excitation densities which is not in accordance wi
th the semiconductor Bloch equations lias been revealed in recent expe
riments on fs time-resolved coherent wave mixing under high magnetic f
ield. We present a rigorous theory of strongly correlated magneto-exci
tons which is based on the coherent truncation scheme. Due to the rest
riction of excitonic degrees of freedom by the magnetic field Coulomb
correlation effects are strongly enhanced. Om numerical results for Ga
As explain most of the experimental findings. Especially we can show t
hat the slow rising time of the time-integrated four-wave mixing signa
ls results from the non-Markovian coupling of the polarization to biex
citonic continuum states.