Giant excitonic magneto-Stark effect in wide GaAs/AlGaAs quantum wells

We have studied the magneto-Stark effect of exciton states with large wave vectors, significantly exceeding the wave vector of light. This magneto-Stark effect can be called “giant” in comparison with a similar effect observed in bulk materials in comparable magnetic fields. In this work, we propose a microscopic model of the “giant” magneto-Stark effect. The model does not contain any free parameters. The numerical results obtained in the framework of this model quantitatively describe the experimental results published earlier in Ref. S. Y. Bodnar et al., (2017) for a heterostructure with a wide GaAs/AlGaAs quantum well in a magnetic field. •The previously experimentally discovered change in the dependence of the exciton energy on its wave vector in wide GaAs/AlGaAs quantum wells in a magnetic field is interpreted in terms of the giant magneto-Stark effect.•A theory of the effect that takes into account the mixing of states of light- and heavy-hole excitons is proposed. Numerical simulation describes the observed effect without using fitting parameters.•The diamagnetic shift of the excitonic energy prevents the ionization of the exciton by the effective electric field in the giant magneto-Stark effect.