Ferromagnetism mediated by the upper Hubbard band in selectively doped GaAs/AlGaAs structures
N. V. Agrinskaya, V. I. Kozub
Ioffe Institute, 194021 S. Petersburg, Russia
Abstract
We consider in detail the indirect exchange between Mn ions imbedded to
GaAs/AlGaAs quantum wells where the barriers are
doped by acceptor impurity supported by the carriers of the upper Hubbard
band supplied by barriers acceptors. A special attention is paid to an
interplay between strong delocalization of the carriers within the upper
Hubbard band (allowing exchange between
well separated ions) and relatively weak coupling of these carriers with Mn
ions. It is shown, that, despite of the latter factor, the values of Curie
temperatures can for such structures be as high as room temperatures.