HOLES IN SEMIMAGNETIC SEMICONDUCTORS

In semimagnetic semiconductors (SMSCs), the strong exchange interaction between spins of an electron or a hole and magnetic ions leads to the formation of a magnetic polaron. Unlike an electron the spatial distribution of magnetic ion spins in the acceptors-bound magnetic polaron is nonuniform. The ground energy state splits into four non-equidistant sublevels. The energy, the free energy and the magnetization of the acceptor-bound polaron are studied as a function of temperature. In (Hg,Mn)Te, oscillations of the photoluminescence (PL) intensity as a function of magnetic field H were observed. The exchange integral was determined from the period of these oscillations. The exchange interaction enhances g-factor and as a result the acceptor ionization energy is a nonmonotonic function of H. This fact may be the reason of the anomalously strong dependence of the PL intensity connected with the conduction-band-acceptor transition. The exchange interaction provides the effective relaxation of the magnetization. Therefore the light induced magnetization should be anomalously small in cubic semiconductors. © 1989.