Effect of the high magnetic field on the localization length in n-type Cooper Indium diselenide

Variable range hopping conduction of the Mott type, where the magnetoresistance follows the relation ρ ( B ) = ρ o exp [ T o ( B ) / T ] 1 / 4 , is observed in n-type CuInSe2 below 20 K at different magnetic field values up to 35 T. The field dependence of the localization temperature T o and localization length ξ can be explained with the existing theoretical models but only up to 10 T. In the high field regime, above 10 T, the magnetoresistance shows a tendency to saturate. However, excellent agreement with the theory of the variation of the hopping parameters T o and ξ with B is found up to 35 T from the analysis of the interpolated magnetoresistance data obtained from the linearly extrapolated plot of Ln ρ ( B ) / ρ ( 0 ) against B 1 / 3 . This suggests that the departure of T o and ξ from the expected variation with B above 10 T is due to the effect of saturation of the magnetoresistance whose origin is not yet clear. To cite this article: L. Essaleh et al., C. R. Physique 8 (2007).