Article

# Thermodynamic signature of a two-dimensional metal-insulator transition

Department of Physics and Astronomy, University of California at Los Angeles, Los Angeles, California 90095, USA.

Physical Review Letters (Impact Factor: 7.73). 06/2000; 84(20):4689-92. DOI: 10.1103/PhysRevLett.84.4689 Source: PubMed

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**ABSTRACT:**We extend the Morel-Anderson model, originally developed to account for the superconductive transition temperature, Tc, of the elements, so that it accounts for the complete phase line for Tc of disordered systems over the full range of metallic behavior, from the pure metal to the extinction of the metallic state at the metal-insulator transition. The cornerstone of this model is the calculation of the BCS interaction potential, V, and the single-particle density of states, N, using the Landau theory for interacting fermions evaluated with a screened Coulomb interaction potential. Thus, an interpolation is established between Fermi liquid behavior and the critical regime where disorder and Coulomb interactions define the metal-insulator transition. Experimental values for Tc, N, and V were compared with these predictions and the agreement was excellent. Furthermore, since the model is expressed entirely in terms of parameters that may be calculated or measured, it has predictive powers that may prove useful in the search for high-Tc materials.Physical Review B 09/2003; · 3.66 Impact Factor - [Show abstract] [Hide abstract]

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**ABSTRACT:**Interacting two-component Fermi gases loaded in a one-dimensional (1D) lattice and subjected to a harmonic trapping potential exhibit interesting compound phases in which fluid regions coexist with local Mott-insulator and/or band-insulator regions. Motivated by experiments on cold atoms inside disordered optical lattices, we present a theoretical study of the effects of a correlated random potential on these ground-state phases. We employ a lattice version of density-functional theory within the local-density approximation to determine the density distribution of fermions in these phases. The exchange-correlation potential is obtained from the Lieb-Wu exact solution of Fermi-Hubbard model. On-site disorder (with and without Gaussian correlations) and harmonic trap are treated as external potentials. We find that disorder has two main effects: (i) it destroys the local insulating regions if it is sufficiently strong compared with the on-site atom-atom repulsion, and (ii) it induces an anomaly in the inverse compressibility at low density from quenching of percolation. For sufficiently large disorder correlation length the enhancement in the inverse compressibility diminishes.International Journal of Modern Physics B 01/2012; 22(25n26). · 0.46 Impact Factor

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