  In this chapter quantum many body theoretical methods have been used to study
properties of GaAs - and InAs - based, small semiconductor compound quantum
dots (QDs) containing manganese or vanadium atoms. Interest to such systems has
grown since experimental synthesis of nanoscale magnetic semiconductors, that
is, nanoscale semiconductor compounds with enhanced magnetic properties. This
enhancement is achieved by several methods, and in particular by doping common
semiconductor compounds with some atoms, such as Mn or V. Experimental studies
indicate that the electron spin density in the case of thin nanoscale magnetic
semiconductor films and QDs may be delocalized. As described in this chapter,
quantum many body theory-based, computational synthesis (i.e., virtual
synthesis) of tetrahedral symmetry GaAs and InAs small pyramidal QDs doped with
sabstitutional Mn or V atoms proves that such QDs are small magnetic molecules
that indeed, possess delocalized and polarized electron spin density. Such
delocalization provides a physical mechanism responsible for stabilization of
these nanoscale molecular magnets, and leads to the development of what can be
described as spin-polarized holes of the electron charge deficit. In some QDs,
numerical values of the electron spin density distribution are relatively
large, indicating that such semiconductor systems may be used as nanomaterials
for spintronic and magneto-optical sensor applications.
