METAL-INSULATOR TRANSITIONS IN THE DISORDERED HUBBARD-MODEL

Quantum Monte-Carlo methods are used to study the disordered Hubbard m odel in infinite dimensions. The averaged local moment and thermodynam ic compressibility are calculated at half filling to determine the met al-insulator transitions in the paramagnetic phase. Two transitions of different physical origin are found: one driven by disorder, the othe r one by interactions. Taking into account the additional paramagnet-a ntiferromagnet transition this simple model of interacting electrons i n a random potential is found to have a rich phase diagram.