Magnon Corrections to the Effective Mass of an Electron in a Magnetic Semiconductor

Abstract

We have computed the renormalization of the conduction-electron energy in a degenerate ferromagnetic semiconductor at zero temperature due to the virtual emission and reabsorption of spin waves. We find that as a result of the difference between the up- and down-spin Fermi momenta, this renormalization is quite small. However, in the case where the conduction electrons are antiferromagnetically coupled to the ionic moments, it is possible by doping to achieve a situation in which the effective mass of the down-spin electrons is increased by about 30%, while the up-spin electrons remain unaffected.