Exciton magnetic polarons in semimagnetic quantum wells and superlattices

Abstract
We review the experimental and theoretical investigations of static and dynamical properties of magnetic polarons in CdTe/(Cd,Mn)Te quantum wells and superlattices. Magnetic polarons are formed from excitons primarily localized on the fluctuations of quantum well width (or fluctuations of superlattice periods). The polaron energy has been measured as a function of structure parameters, temperature and external magnetic fields applied parallel and perpendicular to the growth axis. Dynamics of the magnetic polaron formation has been studied by use of picosecond time-resolved luminescence. A theory of magnetic polarons in quantum wells developed in the adiabatic approximation gives good qualitative description of the experimental results. A strong effect of the spin-glass phase modification at interfaces on the magnetic polaron energies in quantum wells and superlattices has been found.