Carrier spin relaxation in diluted magnetic quantum wells: Effect of Mn spin correlations
Résumé
We demonstrate theoretically that the presence of holes, either resident or photocreated, in diluted magnetic quantum wells accelerates the spin relaxation of electrons via a mechanismwhich has been previously overlooked. This effect is due to the spin correlations, which establish between magnetic ions coupled via hole-mediated Ruderman-Kittel-Kasuya-Yoshida interactions in the paramagnetic phase. As a consequence, the electron spin relaxation becomes temperature and hole density dependent, in contrast to existing theories. Our theory qualitatively reproduces the increase of the electron spin relaxation rate with pump power observed in n-doped CdMnTe magnetic quantum wells [Ben Cheikh et al., Phys. Rev. B 88, 201306 (2013)]. It also predicts a decrease of the spin relaxation rate with temperature, as observed, although not in the same temperature range.