EXCESS 1 F NOISE IN SYSTEMS WITH AN EXPONENTIALLY WIDE SPECTRUM OF RESISTANCES AND DUAL UNIVERSALITY OF THE PERCOLATION-LIKE NOISE EXPONENT/

The excess 1/f noise in a random lattice with bond resistances r simil ar to exp(-lambda x), where x is a random variable and lambda much gre ater than 1, is studied theoretically. It is shown that if the correla tion function {delta r(2)}similar to r(theta+2), then the relative spe ctral density of the noise in the system is expressed as C-e similar t o lambda(m) exp(-lambda(1-p(c)), where p(c) is the percolation thresho ld and m = vd (v is the critical exponent of the correlation length an d d is the dimensionality of the problem). It is hypothesized that the exponent m possesses a dual universality: It is independent of 1) the geometry of the lattice and 2) the theta-mechanism responsible for th e generation of the local noise. Numerical modeling in a three-dimensi onal lattice gives m = 2.3 for theta = 1 and theta = 0, in agreement w ith the hypothesis. (C) 1996 American Institute of Physics.