LOW-TEMPERATURE CONDUCTIVITY OF (ZN1-XMNX)3AS2 SOLID-SOLUTIONS

The electrical conductivity of (Zn1-xMnx)3AS2 solid solutions with 0 less-than-or-equal-to x less-than-or-equal-to 0.13 has been measured in the temperature interval of 4.3 < T < 200 K. It is shown that the conductivity is of activational nature. The data are analysed with a model based on the disorder of Mn atoms over the vacancy-type sites of the metallic sublattice. At low temperatures the conductivity is determined by hopping of holes over the states in the lower Hubbard band whereas at high temperatures the holes are activated to states higher than the mobility edge of the upper Hubbard band. The observed complex dependence of the conductivity and the high-temperature activation energy on x are explained in terms of an increasing contribution of multiple spin-flip scattering of holes during their transitions between acceptor centres when x is increased.