Glassy Behavior of Electrons Near Metal-Insulator Transitions

The emergence of glassy behavior of electrons is investigated for systems close to disorder-driven and interaction-driven metal-insulator transitions. Our results indicate that Anderson localization effects strongly stabilize such glassy behavior, while Mott localization tends to suppress it. We predict the emergence of an intermediate metallic glassy phase separating the insulator from the normal metal. This effect is expected to be most pronounced for sufficiently disordered systems, in agreement with recent experimental observations.

Figure 1

Phase diagram for the $z=3$ Bethe lattice, valid in the large disorder limit. The inset shows ${\chi }^{(2)}$ as a function of disorder $W$.

Figure 2

Global phase diagram for the disordered Hubbard model, as a function of the hopping element $t$ and the disordered strength $W$, both expressed in units of the on-site interaction $U$. The size of the metallic glass phase is determined by the strength of the intersite interaction $V$.