Luminescence of coupled quantum wells: Effects of indirect excitons in high in-plane magnetic fields

Abstract

Luminescence measurements of a ${\mathrm{Ga}}_{1\ensuremath{-}x}{\mathrm{Al}}_{x}\mathrm{As}∕\mathrm{Ga}\mathrm{As}$ double quantum well in in-plane magnetic fields up to $22\phantom{\rule{0.3em}{0ex}}\mathrm{T}$ are reported. The properties of spatially direct and indirect excitons are studied. We show that the strong indirect exciton luminescence survives in samples with low nonradiative recombination up to high in-plane magnetic fields. This contrasts with previously published results, where its strong suppression, observed for magnetic fields as low as of $10\phantom{\rule{0.3em}{0ex}}\mathrm{T}$, was explained by the exciton center-of-mass momentum conservation. We attribute the discrepancy to a relatively low nonradiative recombination in the studied sample in comparison with the radiative recombination of localized indirect excitons.