Percolation approach to the metal-insulator transition in two dimensions

A simple non-interacting-electron model, combining local quantum tunneling via quantum point contacts and global classical percolation, is introduced in order to describe the observed "metal-insulator transition" in two dimen sions.(1) It is shown that many features of the experiments, such as the ex ponential dependence of the resistance on temperature on the metallic side, the linear dependence of the exponent on density, the e(2)/h scale of the critical resistance, the quenching of the metallic phase by a parallel magn etic field and the non-monotonic dependence of the critical density on a pe rpendicular magnetic field, can be naturally explained by the model.