Transient level crossing of free and bound excitonic magnetic polarons in Cd1-xMnxTe

摘要

We report an experimental evidence of the existence of free excitonic magnetic polaron (FEMP) states from the study of the dynamics of free and bound excitons in Cd1-xMnxTe (x = 0.03) by time-resolved photoluminescence measurements. We found, for the first time, that FEMP are more stable than the polarons formed from hound excitons, The polaron binding energy for the free excitons is evaluated to be 4 meV, which is considerably larger than that of 1 meV found for the magnetic polarons of the bound excitons; these values were determined from the suppression of the excitonic energy relaxation in high magnetic fields. As a consequence, the peak energies of the optical emissions of free excitons and donor-hound excitons cross in the time-resolved photoluminescence spectra. (C) 2001 Elsevier Science B.V. All rights reserved. [References: 20]