27 research outputs found
Ultrafast spin dynamics in II-VI diluted magnetic semiconductors with spin-orbit interaction
We study theoretically the ultrafast spin dynamics of II-VI diluted magnetic
semiconductors in the presence of spin-orbit interaction. Our goal is to
explore the interplay or competition between the exchange -coupling and the
spin-orbit interaction in both bulk and quantum well systems. For bulk
materials we concentrate on ZnMnSe and take into account the
Dresselhaus interaction, while for quantum wells we examine
HgMnCdTe systems with a strong Rashba coupling. Our
calculations were performed with a recently developed formalism which
incorporates electronic correlations beyond mean-field theory originated from
the exchange -coupling. For both bulk and quasi-two-dimensional systems we
find that, by varying the system parameters within realistic ranges, both
interactions can be chosen to play a dominant role or to compete on an equal
footing with each other. The most notable effect of the spin-orbit interaction
in both types of systems is the appearance of strong oscillations where the
exchange -coupling by itself only causes an exponential decay of the mean
electronic spin components. The mean-field approximation is also studied and it
is interpreted analytically why it shows a strong suppression of the
spin-orbit-induced dephasing of the spin component parallel to the Mn magnetic
field.Comment: 9 pages, 5 figure