Sv. Goupalov et Av. Kavokin, CRITICAL CONDITIONS FOR CHARGED AND NEUTRAL MAGNETIC BIPOLARON FORMATION IN 1D, 2D AND 3D SYSTEMS, Solid state communications, 97(2), 1996, pp. 77-82
Interaction of two magnetic polarons formed either by single carriers
or by excitons is considered in bulk crystals, quantum wells and quant
um wires. It is shown that the magnetic bipolaron can be formed if the
distance between two polarons is less than some critical value. This
critical radius is larger, the lower the temperature and the larger th
e single polaron radius. Carrier-carrier exchange interaction is shown
to be less important for the bipolaron formation than the exchange co
upling between carriers and magnetic ions. Charged magnetic bipolarons
are expected to be found mostly in semimagnetic quantum wires, while
the neutral ones can be observed in any system where the free exciton
magnetic polaron can be formed. The critical distance for the neutral
magnetic bipolaron formation is much longer than for the charged bipol
aron.