Charge transport and metal-insulator transition in correlated and disordered systems

The metal-insulator transition induced by sufficiently strong short range repulsive electron-electron interaction U is called Mott-Hubbard transition. In this work we study the effect of disorder on the critical value of the repulsion U-c. The Hubbard model with random site energies to describe the correlated and disordered system has been used. The Kotliar-Ruckenstein slave-boson technique to treat correlations and coherent potential approximation (CPA) to deal with disorder have been applied. We have found that the low temperature conductivity is an increasing or decreasing function of U depending on the carrier concentration. The critical value U-c for metal-insulator transition is decreasing function of the disorder strength.