Magnetically Enhanced Exciton-Exciton Correlations in Semiconductors

We present investigations of fs time resolved coherent wave mixing under high magnetic field. Our experiments reveal a new regime at high magnetic field and low excitation density dominated by the Coulomb interaction. This regime is inconsistent with the semiconductor Bloch equations. A model which includes exciton-exciton correlation successfully describes many features of this regime. {copyright} {ital 1997} {ital The American Physical Society}