Magnon instability in bulk magnetic semiconductors in two laser fields under quantizing magnetic fields

Abstract

The magnon scattering by electrons in a bulk magnetic semiconductor in two laser fields in the additional presence of a quantizing (strong) magnetic field is considered. An unitary transformation is employed to eliminate the laser fields dependence of the kinetic energy term. In this case the problem of an electron in three external fields will be reduced to the simple problem of an electron in presence only of the magnetic field. A kinetic equation for the magnon population is derived from which the damping rate is calculated. We found that spin waves may be amplified over a relatively narrow range of magnon wavenumbers in the direction perpendicular to the magnetic-field direction. Furthermore, the join action of the three external fields results in a very large amplification rate, in contrast to zero magnetic field case.