Luminescence of indirect excitons in high in-plane magnetic fields

Abstract

We report on low-temperature magneto-luminescence measurements of biased Ga 1 - x Al x As / GaAs double quantum well structures. The luminescence of spatially indirect excitons (IX) is studied up to the magnetic field of 22 T. In contradiction to theoretical predictions and their several experimental confirmations, the IX line survives in PL spectra of our double quantum well structure up to high in-plane magnetic fields. We explain this difference by the IX localization which enables the relaxation of the IX in-plane momentum, whose conservation is responsible for the damping of the IX luminescence intensity observed by other groups. This localization is supported by a relatively weak non-radiative recombination in comparison to the radiative one observed in our double quantum well structure. The IX luminescence was studied under various excitation intensities to obtain deeper insight into the IX localization mechanism. This paper confirms and broadens our previously published results obtained from a double quantum well structure of other width.