The nature of Mn center and exchange interaction in Ga1−xMnxAs dilute magnetic semiconductor

The s,p–d exchange interaction in GaMnAs is discussed in view of different charge states of Mn impurities present in this material. The ferromagnetic to antiferromagnetic crossover of p–d exchange is discussed on the grounds of varying concentration of neutral and ionized Mn acceptor centers in bulk, Mn-doped GaAs and GaMnAs epilayers.