Critical Exponents for Metal-Insulator Transition in Two-Dimensional Systems

Three years ago, a new universality class, associated with the metal-insulator transition in quasi-two-dimensional compounds, was discovered. Imada has given explanation of the observed critical behaviour. Considerations in this work are besed on the assumption that the one-particle dispersion is quartic one instead of the standard quadratic behaviour. In this paper, it is shown that other possible natural non-standard dispersions lead to other possible critical behaviotir and critical exponents.