Spin-flip-induced hole burning in GaAs quantum wells: Determination of the exciton Zeeman splitting

Abstract
A new method of four-wave-mixing spectroscopy in GaAs quantum wells reveals spectral hole burning due to spin relaxation of magnetoexcitons. The measurements resolve the Zeeman doublet of the lowest-energy heavy-hole exciton where the doublet splitting is much less than the exciton inhomogeneous width. The Zeeman splitting depends nonlinearly on the magnetic field and is small compared with that of bulk GaAs. The results reflect effects of the complex band structure of quantum wells. Information on exciton spin relaxation is also provided by the hole-burning measurements.