ANALYTIC SCALING FUNCTIONS FOR PERCOLATIVE METAL-INSULATOR PHASE-TRANSITIONS FITTED TO ALXGE1-X DATA

The definition of the percolation scaling functions and an equation fo r the conductivity of a binary composite are combined to obtain two pe rcolation scaling functions F+(x(+)) and F-(x(-)). F+(x(+)) is the fun ction valid above the percolation threshold (phi(c)) and F-(x(-)) belo w. Using numerical simulation, it is then shown that these two functio ns display the principle properties required for them to be scaling fu nctions. Previously reported experimental data on AlxGe1-x, where phi( c) was determined from superconductivity measurements, is replotted in the scaling form and shown to agree with the ''best fit'' F+(x(+)) an d F-(x(-)). (C) 1998 Elsevier Science B.V. All rights reserved.