Metal-insulator transition in two-dimensional Ando model

The transport properties of the Ando model on square lattice are studied numerically for box distribution of the diagonal disorder. The statistical properties of the Lyapunov exponents and of the conductance are discussed. It is shown that the statistics of the Lyapunov exponents agrees with the random matrix theory not only in the metallic regime, but even at the critical point. That confirms the applicability of the random matrix theory to the description of trie metal-insulator transition. The limiting distribution of the conductance at tl~e critical point of the metal-insulator transition is presented and its form is discussed on trie base of the statistics of the Lyapunov exponents. Fluctuations of the conductance in the metallic and of the logarithm of the conductance m the insulating regimes indicate that trie theory of trie metal-insulator transition is one-parametric.