Hubbard physics in the symmetric half-filled periodic anderson-hubbard model

Abstract

Two very different methods — exact diagonalization on finite chains and a variational method — are used to study the possibility of a metal-insulator transition in the symmetric half-filled periodic Anderson-Hubbard model. With this aim we calculate the density of doubly occupied d sites (gn _d ) as a function of various parameters. In the absence of on-site Coulomb interaction (U _f ) between f electrons, the two methods yield similar results. The double occupancy of d levels remains always finite just as in the one-dimensional Hubbard model. Exact diagonalization on finite chains gives the same result for finite U _f , while the Gutzwiller method leads to a Brinkman-Rice transition at a critical value (U ^c _d ), which depends on U _f and V.