Metal-insulator transition in the compensated sodium bronze,NaxTay

Abstract

We have measured the dc electrical conductivity o of cubic Na"Ta"WI~03 from 1.6 to 295 K for various values of x and y. A sample with x -y=0. 18 appears to fall directly at the metal-insulator transition and shows an unusual temperature dependence, g(T)~T, -from 1.6 K to room temperature. A model for o. (T) based on the scaling theory of localization, when used to interpret the data on this and other samples, gives a conductivity exponent v of 1.0. This model assumes that o. (T) is controlled by a thermal smearing of the occupancy of one-electron energy states near the Fermi level rather than by inelastic scattering. Comparison of the conductivity transition in Na"Ta~WI yQ3 with earlier data for the uncompensated material Na"WO3 indicates that the additional disorder introduced by Ta doping does not shift the critical value of electron concentration.

Interplay between the magnetic and transport properties in the III-V diluted magnetic semiconductorGa1−xMnxEsch1, Bockstal2, Boeck3 et al. 1997Phys. Rev. B390172772View full textAdd to dashboardCite

“…9͒ show a transport behavior characteristic for systems near the metalinsulator transition, where the resistivity is inversely proportional with temperature. Dubson and Holcomb 21 derived the temperature dependence of the conductivity near the MIT point from the energy dependence of the zero-temperature conductivity properties around the Fermi level. When applied to hole transport, this temperature dependence is given by…”

Spin-Dependent Transport in Heavily Mn-Doped GaAs

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Electronic structure of transition-metal chalcogenides and their intercalation compounds

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