The metal-insulator transition (MIT) induced by a magnetic field. in barely metallic and compensated n-type InP has been re-examined. Using new analysis methods, we have determined the magnetic field for which the conductivity change from a metallic behaviour to avariable-range hoppingregime. On themetallicsideoftheMl~, the electricalmnduciivity is found to obey a = a. + mT' down to 60 mK: the zero-temperature conductivity can be described by a scaling law with an exponent U = 1 and there is no evidence for a minimum metallic conductivity.As the MIT is approached, we observe a clear crossover from a T''' to T"' temperature dependenceofthemnductivity, which is related toacompetition between two lengthscales: the correlation length and the interaction length.

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We present magnetoresistance measurements on a metallic n-type InP sample on both sides of the metal-insulator transition (MIT). On the metallic side of the MIT, we have observed negative magnetoresistance behaviour, and the experimental data are interpreted in terms of the weak localization and the effect of electron-electron interactions. On the insulator side of the MIT, we have observed positive magnetoresistance associated with variable range hopping conduction. In both cases, experimental data are compared with available theoretical models.

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