Optical orientation of excitons induced by an energy-level anticrossing and by cross-relaxation in type-I GaAs/AlAs superlattices
Baranov P. G. , Vetrov V. A. , Namozov B. R., Romanov N. G.
An optical orientation of excitons has been observed in type-I GaAs/AlAs superlattices in a narrow interval of magnetic fields during nonresonant excitation by unpolarized light. The magnetic field strength at which the optical orientation occurs depends sharply on the direction of the field with respect to the plane of the superlattice. The optical orientation is determined from the circular polarization of luminescence. It reaches a magnitude of 10%. It is attributed to an anticross-ing of exciton energy levels. Some additional optical-orientation peaks which are observed are caused by a cross-relaxation. © 1995 American Institute of Physics.