We study the influence of electron-electron interactions on the electronic properties of disordered materials. In particular, we consider the insulating side of a metal-insulator transition where screening breaks down and the electron-electron interaction remains long ranged. The investigations are based on the quantum Coulomb glass, a generalization of the classical Coulomb glass model of disordered insulators. The quantum Coulomb glass is studied by decoupling the Coulomb interaction by means of a Hartree-Fock approximation and exactly diagonalizing the remaining localization problem. We investigate the behavior of the Coulomb gap in the density of states when approaching the metal-insulator transition and study the influence of the interaction on the localization of the electrons. We find that the interaction leads to an enhancement of localization at the Fermi level.
F. Epperlein et al., "Quantum Coulomb Glass within a Hartree-Fock Approximation," Physical Review B - Condensed Matter and Materials Physics, vol. 56, no. 10, pp. 5890-5896, American Physical Society (APS), Sep 1997.
The definitive version is available at http://dx.doi.org/10.1103/PhysRevB.56.5890
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