Exciton ionization induced by giant magneto-Stark effect

The suppression of the amplitude of spectral features related to exciton states with large wave vectors is observed in the reflectance spectra of heterostructures with wide quantum wells in a transverse magnetic field (Voigt geometry). This effect becomes stronger with increasing exciton wave vector. This phenomenon is caused by the weakening of the exciton-light coupling and the ionization of excitons by the effective electric field arising due to the magneto-Stark effect. An accurate microscopic theory that describes the exciton-light coupling of states with large wave vectors in a transverse magnetic field has been developed. The reflectance spectra calculated within this theory show good agreement with the experimental data.