Pair-correlation function of random diode-insulation network

Pair-correlation function of the random diode-insulation network on a square lattice is obtained by the Monte Carlo simulation. Each bond is occupied by one of a positive diode, a negative diode and an insulation with probability p(+), p(-) and 1 - p(+) - p(-), respectively. We define positive diodes to be transmitting either upward or to the right and vice versa for negative diodes. This system exhibits continuous phase transitions signaling the appearance of an infinite self-affine cluster. We estimate the critical points and critical exponents by the time-dependent simulation and find the pair-correlation function at the critical point is characterized by the same exponent with fully directed percolation model.