Critical conductivity at the magnetic-field-induced metal-insulator transition in n-GaAs and n-InSb

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Abstract
The authors present results on the magnetic-field-induced metal-insulator transition in the direct-gap III-V semiconductors GaAs and InSb. The experiments were carried out at temperatures (T) as low as 40 mK and in magnetic fields of up to 9T. They find that at the metal-insulator transition, the conductivity, sigma , can be expressed in the form sigma = zeta T13/, where zeta is a constant depending on the density of states, giving good quantitative agreement with recent theories of the interaction-driven metal-insulator transition due to Finkel'shtein (1983), extended by Altshuler and Aronov (1983) and by Castellani and coworkers (1984).