Mesoscopic fluctuations of conductance in two-dimensional percolation gold films near the percolation threshold

The conductivity of two-dimensional inhomogeneous Au films near the percolation threshold is investigated in the temperature interval 0.5–55 K. The percolation threshold was approached by irradiation of initially continuous films (of thickness ∼ 10 nm) by Ar ions. It is found that near the percolation threshold (on the insulating side of the metal–insulator transition), the film exhibits one-dimensional hopping conduction. The fluctuations of hopping conductivity were also observed. It is shown that the conductivity of a two-dimensional percolation film in the vicinity of the percolation threshold can be determined by a single conducting chain. The presence of narrow insulating bridges in this chain determines the one-dimensional behavior of hopping conduction of the entire system as well as the observed resistance fluctuations. These fluctuations can be treated as a peculiar manifestation of incoherent mesoscopic effects.