Green function theory of magnon sideband shapes in antiferromagnetic crystals

Abstract

Green function methods are used to include the effects of exciton-magnon interaction in a calculation of the shapes of magnon sidebands on narrow exciton lines in antiferromagnets. The general theory is applied to RbMnF3, for which crystal numerical results are presented. It is found that good agreement with experimental results for the 6A1 to 4T1 exciton transition can be obtained if the exchange constant between a neighbouring 6A1-4T1 pair of manganese ions is about one-half of the exchange constant for a 6A1-6A1 pair.