BAND TAILS IN DILUTED MAGNETIC SEMICONDUCTORS

Tails in the density of electron states in diluted magnetic semiconduc tors are examined theoretically. The exchange interaction between a ch arge carrier and magnetic ions makes the energy dependence of the dens ity of states in the tails markedly different from those known for non magnetic solid solutions. The cases of uncorrelated and strongly corre lated disorder are analyzed. In both cases the density of states in th e tail turns out to be nonmonotonic. In the case of uncorrelated disor der the density of states has a gap, while it possesses a deep valley in the case of strongly correlated disorder. The thermal disorder in t he spin system of the ions makes the density of states temperature dep endent. Some possible experimental manifestations of these features of the tails in diluted magnetic semiconductors are discussed.