We present a theory for disordered interacting electrons that can describe both the Mott and Anderson transitions in the respective limits of zero disorder and zero interaction. We use it to investigate the $T=0\mathrm{}$ Mott-Anderson transition at a fixed electron density, as the disorder strength is increased. Surprisingly, we find two critical values of disorder $W_{\mathrm{nfl}}$ and $W_c$. For $W>\mathrm{}{W}_{\mathrm{nfl}}$, the system enters a “Griffiths” phase, displaying metallic non-Fermi liquid behavior. At even stronger disorder, ${W=W}_c>W_{\mathrm{nfl}}$ the system undergoes a metal-insulator transition, characterized by the linear vanishing of both the typical density of states and the typical quasiparticle weight.

• Received 4 November 1996

DOI:https://doi.org/10.1103/PhysRevLett.78.3943