Critical conductivity for semiconductor-metal alloys

Classical ionized impurity scattering is employed to calculate the conductivity at and near the critical point. The result sigma(x = x(c), T) = A root T is nearly universal, A is weakly dependent on the form of the density-of-states above the mobility edge, and can explain the root T term observed for amorphous semiconductor-metal alloys. The result is compared with the Altshuler-Aronov correction delta sigma(D) = m(n)root T resulting from electron-electron interactions, sigma(x > x(c), T) can also explain the linear scaling behavior sigma(x, T) - A root T = sigma(0)(x/x(c) - 1). (C) 2000 Elsevier Science B.V. All rights reserved.