Shot-noise suppression at two-dimensional hopping

We have used Monte Carlo simulation to calculate the shot-noise intensity S-1(omega) at (two-dimensional) hopping using two models: a slanted lattice of localized sites with equal energies and a set of localized sites with random positions and energies. For wide samples we have found a similar dependence of the Fano factor F equivalent to S-1(0)/2eI on the sample length L: F proportional to L-alpha where alpha = 0.85+/-0.02 and alpha = 0.85+/-0.07 in uniform and random models, respectively. Moreover, at least for the uniform model, all the data for F as the function of sample length L and width W may be presented via a single function of the ratio W/L-beta, with beta = 2 alpha -1 approximate to 0.7. This relation has been interpreted using a simple scaling theory.