Percolation of aligned dimers on a square lattice

Percolation and jamming phenomena were investigated for anisotropic sequential deposition of dimers (particles occupying two adjacent adsorption sites) on a square lattice. The influence of dimer alignment on the electrical conductivity was examined. The percolation threshold for deposition of dimers was lower than for deposition of monomers. Nevertheless, the problem belongs to the universality class of random percolation. The lowest percolation threshold (p(c) = 0.562) was observed for isotropic orientation of the dimers. It was higher (p(c) = 0.586) in the case of dimers aligned strictly along one direction. The state of dimer orientation influenced the concentration dependence of the electrical conductivity. The proposed model seems to be useful for description of the percolating properties of anisotropic conductors.