In R. Rosenbaum, A. Heines, A. Palevski, M. Karpovski, A. Gladkikh, M. Pilosof, A. J. Daneshvar, M. R. Graham, T. Wright, J. T. Nicholls, C. J. Adkins, M. Witcomb, V. Prosesky, W. Przybylowicz, R. Preterious, J. Phys.: Condens. Matter. 9, 5395–5411 (1997), the authors have observed a metal-insulator transition in films Si1-xNix at xc=0.24 and observed WL and EEI phenomena at low temperatures. Using results obtained on these films we have performed calculations using Boltzmann’ theory and weak localization theory near the MIT. Our new results show that Ioffe-Regel criterion is obeyed and the conduction is governed by weak localization and electron electron interactions phenomena, in agreement with the results obtained by Rosenbaum et al.

The magnetoconductivity of quasicrystals is often discussed in the frame of quantum corrections, namely weak (anti-) localisation and electron–electron interaction. A premise for both effects is a strong elastic scattering of conduction electrons. Amorphous and icosahedral phases are discussed as Hume–Rothery alloys with an electronically induced structural peak at the diameter of the Fermi sphere. Therefore, both should exhibit quantum corrections. The preparation of quasicrystalline films via the amorphous route offers the possibility to compare the magnetoconductivity on samples of identical composition but different structure. We report on magnetoconductivity measurements at temperatures between 0.2 and 22K and for magnetic fields up to 16T. With the exception of the electronic diffusion constant, amorphous as well as icosahedral Al–Pd–Re films can be described by nearly the same set of parameters if the samples are well on the metallic side of the metal–insulator transition.

The electrical conductivity and magnetoconductance (MC) have been measured in crystalline nickel-silicon films as a function of nickel content, x. An abrupt decrease in the conductivity is observed at the metal-insulator transition where Ni. The discontinuity is explained in terms of a percolation model. Above 4 K, the magnetoconductance (MC) is negative and arises from an electron-electron interaction contribution and a weak-localization contribution involving strong spin-orbit scattering. Below 4 K, the magnetoconductance rapidly becomes positive. These low-temperature MC data can be explained using a model of electrons scattering from superparamagnetic particles, first introduced by Gittleman et al.

The electronic conductivity has been measured in homogeneous, weakly insulating, amorphous nickel - silicon films located just below the metal - insulator transition (MIT). The conductivity follows a simple power-law dependence with over a large temperature interval. In contrast, a Mott variable-range hopping expression could not be fitted successfully through these zero-field conductivity data. The behaviour can be explained using the three-dimensional (3D) electron - electron interaction (EEI) theory. The negative magnetoconductance data observed in these weakly insulating films can be fitted nicely using only the 3D EEI theory. A crossover of the conductivity from the simply power-law dependence at high temperatures to an activated hopping-law dependence in the liquid helium temperature region is observed; this transition is attributed to changes in the energy dependence of the density of states near the Fermi level. The conductivity of these weakly insulating films can be fitted well over three decades of temperature using an empirical scaling expression suggested by Möbius et al.

Transport properties including conductivity and magnetoconductance have been measured for amorphous nickel - silicon films. This study focuses on metallic amorphous films, located just above the metal - insulator transition (MIT). Using various techniques, the MIT was identified. Electron - electron interactions dominated the conductivity, where . Strong spin - orbit scattering was important in the weak-localization contribution to the magnetoconductance data for the metallic films. The inelastic scattering time was extracted from the magnetoconductance data. The low-temperature magnetoconductance data versus Ni content x exhibited a negative maximum just above the critical concentration , suggesting another technique for identifying the MIT.