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In-plane optical anisotropy due to conduction band electron wavefunctions

J. Łusakowski·M. Sakowicz·K. J. Friedland·R. Hey·K. Ploog
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Abstract

Photoluminescence measurements were carried out on Be $δ$-doped GaAs/Al$_{0.33}$Ga$_{0.67}$As heterostructure at 1.6 K in magnetic fields ($B$) up to 5 T. Luminescence originating from recombination of a two-dimensional electron gas (2DEG) and photo excited holes localized on Be acceptors was analyzed. The degree of circular polarization ($γ_C$) of the luminescence from fully occupied Landau levels was determined as a function of $B$ and the 2DEG concentration, $n_s$. At $B$ constant, $γ_C$ decreased with the increase of $n_s$. Two mechanisms of the $γ_C(n_s)$ dependence are discussed: a) the Stark effect on a photo excited hole bound to Be acceptor and b) the in-plane anisotropy of the intensity of optical transitions. A quantitative analysis shows that the influence of the Stark effect on $γ_C$ is negligible in the present experiment. We propose that the $γ_C(n_s)$ dependence results from the $C_{2v}$ symmetry of conduction band electron wavefunctions and we give qualitative arguments supporting this interpretation.

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J. Łusakowski, M. Sakowicz, K. J. Friedland, R. Hey, K. Ploog. 2007-03-05. In-plane optical anisotropy due to conduction band electron wavefunctions. https://arxiv.org/abs/cond-mat/0703088

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