Third International Conference on Optics of Excitons in Confined

Le Journal de Physique IV 03 (1993) C5-183-C5-186
DOI: 10.1051/jp4:1993534

Anisotropic exciton states in GaAs/AlAs superlattices in zero and non-zero magnetic field

C. GOURDON¹, D.Yu. RODICHEV², P. LAVALLARD³, G. BACQUET⁴ and R. PLANEL<sup>5

1</sup>  Groupe de Physique des Solides, URA 17 du CNRS, Universités Paris 6 et 7, 2 place Jussieu, 75251 Paris / cedex 05, France
²  Physics Department, Moscow State University, Lenin Hills, 117234 Moscow, Russia
³  Groupe de Physique des Solides, URA 17 du CNRS, Universités Paris 6 et 7, 2 place Jussieu, 75251 Paris cedex 05, France
⁴  Laboratoire de Physique des Solides, URA 74 du CNRS, INSA, avenue de Rangueil, 31077 Toulouse cedex, France
⁵  L2M-UP CNRS 20, 196 avenue H. Ravera, 92220 Bagneux, France

Abstract
In short period pseudodirect GaAs/AlAs superlattices, the two radiative heavy exciton states exhibit a very small anisotropic splitting due to their coupling with light exciton states. They are dipole-active along the [110] and [1(-1)0] directions in the layer plane. The splitting energy (a few µeV) is obtained from the period of the quantum beats between the two sublevels observed during the time decay of photoluminescence under excitation with light linearly polarized along [101] or circularly polarized. We report here on the variation of the quantum beats in a magnetic field. In a longitudinal field (parallel to the wave vector of light), we measure the splitting between the radiative states and obtain the hole longitudinal g-factor. In a transverse field, we observe two periods for the quantum beats. One corresponds to the splitting between the radiative states and the other to the splitting between the radiative states and the non-radiative ones which become optically allowed in a transverse field. We also discuss the influence of the coupling to light excitons in a transverse field on the hole transverse g-factor.

© EDP Sciences 1993