We report three photoluminescent lines in the 1.504-1.507 eV range in
GaAs, associated with excitons bound to defect pairs. The lines are al
l split by crystal field interaction introduced by uniaxial stress. Th
e highest energy line is strongly polarized in the [110] direction. Th
e polarization selection rules are relaxed by an applied magnetic fiel
d clearly demonstrating the crystal field splitting. (C) 1997 Publishe
d by Elsevier Science Ltd.