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

The conductivity of two-dimensional inhomogeneous Au films near the percolation threshold was studied in the temperature range 0.5-55 K. To achieve the percolation structure, the initial homogeneous films with thicknesses about 10 nm were irradiated with Ar ions. It was found that near the percolation threshold the film shows the evidence for one-dimensional hopping conduction (on the insulating side of metal-insulator transition). The fluctuations of hopping conduction were also observed. It is shown that the behavior of conductivity in two-dimensional film in the vicinity of the percolation threshold can be defined by a single linking chain. The presence of narrow insulating bridges in such chain is responsible for both the one-dimensional behavior of hopping conduction in the whole system and the observed fluctuations of conductivity. These fluctuations can be considered as an unusual manifestation of the effects of incoherent mesoscopics.