2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/209280We show that the study of conductivity nonlinearity gives a possibility to determine the condition when the diffusion conductivity changes to the hopping one with increasing disorder. It is experimentally shown that the conductivity of single quantum well GaAs/InGaAs/GaAs heterostructures behaves like diffusive one down to value of order $10^{-2}e^2/h$.4 pages, 2 figuresDisordered Systems and Neural Networkstext