Percolation Approach to the Metal-Insulator Transition in Super-Critical Fluid Metals

The percolation theory is extended to a thermal equilibrium state of an interacting particle system. By a computer simulation method, percolation process in a square lattice gas model is studied in super-critical regions. Critical percolation density is found to be an increasing function of temperature. The critical index of percolation probability is almost independent of temperature and 0.145±0.027. The result obtained in the lattice gas model is applied to the metal-insulator transition in super-critical fluid metals and an effect of the atomic configuration to the transition is studied. A phase diagram of the transition is obtained. The percolation aspect of the conductivity near the critical point is discussed.