METAL-INSULATOR-TRANSITION IN THE PERSISTENT PHOTOCONDUCTOR CD1-XMNXTE-IN

Persistent photoconductivity has been used to probe the metal-insulato r transition in the diluted magnetic semiconductor Cd1-xMnnTe : In. We have measured the d.c. conductivity of Cd0.92Mn0.08Te : In with tunab le photogenerated carrier concentration, from the insulating phase up to similar to 1.2n(c) in the same sample. In the insulating phase, Efr os-Shklovskii variable range hopping conduction is observed. In the me tallic phase the temperature dependence of the conductivity is adequat ely described by quantum corrections to the zero-temperature conductiv ity due to the effects of electron-electron interaction and weak local ization. In the critical region the scaling theory of electron localiz ation has been applied. We observe a critical carrier concentration si milar to 2.3 x 10(17) cm(-3), and a critical conductivity exponent clo se to one.