Dielectric susceptibility of the Coulomb-glass

We derive a microscopic expression for the dielectric susceptibility X of a Coulomb glass, which corresponds to the definition used in classical electrodynamics, the derivative of the polarization with respect to the electric field. The fluctuation–dissipation theorem tells us that is a function of the thermal fluctuations of the dipole moment of the system. We calculate X numerically for three–dimensional Coulomb glasses as a function of temperature and frequency.We acknowledge financial support from the DGES project number PB96-1118, SMWK, and DFG (SFB 393). A great part of this work was performed during A. D.-S.’s visit at the IFW Dresden; A. D.-S. thanks the IFW for its hospitality

Configuration space in electron glasses

We study numerically the configuration space at low energy of electron glasses. We consider systems with Coulomb interactions, short–range interactions and no interactions. First, we calculate the integrated density of configurations as a function of energy. At a given energy, this density is smaller for Coulomb glasses than for short-range systems, which in turn is smaller than for non– interacting systems. We analyze how the site occupancy varies with the number of configurations. Through this study we estimate the number of particles involved in a typical low–energy transition between configurations. This number increases with system size for long range interactions, while it is basically constant for a short-range interaction. Finally we calculate the density of metastable configurations, i.e. valleys, classified according to their degree of stability.We thank Prof. M. Pollak for useful discussions. We would like to acknowledge financial support from the Spanish DGES, project numbers PB96-1118 and PB96- 1120, and lak and Mfrom the Fundación Séneca, Región de Murcia. A.P.G acknowledges CajaMurcia for a grant

Interacciones de Coulomb en sistemas desornados con fuerte localización / Rafael Chicón Romero ; director Miguel Ortuño Ortín.

Tesis-Universidad de Murcia.Consulte la tesis en: BCA. GENERAL. ARCHIVO UNIVERSITARIO. T.M.-4.CRAI CIENCIAS. DEPOSITO. TD 113