BAND TAILS IN DILUTED MAGNETIC SEMICONDUCTORS

Tails in the density of electron states in diluted magnetic semiconductors are examined theoretically. The exchange interaction between a charge carrier and magnetic ions makes the energy dependence of the density of states in the tails markedly different from those known for nonmagnetic solid solutions. The cases of uncorrelated and strongly correlated disorder are analyzed. In both cases the density of states in the tail turns out to be nonmonotonic. In the case of uncorrelated disorder the density of states has a gap, while it possesses a deep valley in the case of strongly correlated disorder. The thermal disorder in the spin system of the ions makes the density of states temperature dependent. Some possible experimental manifestations of these features of the tails in diluted magnetic semiconductors are discussed.