Phys. Rev. Lett. 71, 2634–2637 (1993)Possible solution of the conductivity exponent puzzle for the metal-insulator transition in heavily doped uncompensated semiconductorsReceived 1 June 1993; published in the issue dated 18 October 1993 The electrical conductivity σ (extrapolated to T=0) of uncompensated Si:P indicates a crossover as a function of P concentration N at Ncr slightly above the metal-insulator transition at Nc. For N>Ncr the exponent of σ∼(N-Nc)μ is μ≊0.64, while μ≊1.3 for Nc<N<Ncr. At Ncr dσ/dT changes sign from negative for N>Ncr to positive for N<Ncr. $sigma— in a magnetic field also yields μ≊1. The apparent discrepancy between uncompensated and compensated semiconductors is traced back to a difference in the (nonuniversal) width of the critical region. © 1993 The American Physical Society URL:
http://link.aps.org/doi/10.1103/PhysRevLett.71.2634
DOI:
10.1103/PhysRevLett.71.2634
PACS:
71.30.+h, 72.80.Cw
See AlsoComment: T. F. Rosenbaum, G. A. Thomas, and M. A. Paalanen, Critical behavior of Si:P at the metal-insulator transition, Phys. Rev. Lett. 72, 2121 (1994). Comment: H. Stupp, M. Hornung, M. Lakner, O. Madel, and H. v. Löhneysen, Stupp et al. Reply, Phys. Rev. Lett. 73, 3601 (1994). Comment: T. G. Castner, Critical Behavior of the Conductivity of Si:P near the Metal-Insulator Transition, Phys. Rev. Lett. 73, 3600 (1994). Reply: H. Stupp, M. Hornung, M. Lakner, O. Madel, and H. v. Löhneysen, Stupp et al. reply, Phys. Rev. Lett. 72, 2122 (1994). |
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