title: Effective temperature in relaxation of Coulomb glasses.
abstract: We study relaxation in two-dimensional Coulomb glasses up to macroscopic times. We use a kinetic Monte Carlo algorithm especially designed to escape efficiently from deep valleys around metastable states. We find that, during the relaxation process, the site occupancy follows a Fermi-Dirac distribution with an effective temperature much higher than the real temperature T. Long electron-hole excitations are characterized by T(eff), while short ones are thermalized at T. We argue that the density of states at the Fermi level is proportional to T(eff) and is a good thermometer to measure it. T(eff) decreases extremely slowly, roughly as the inverse of the logarithm of time, and it should affect hopping conductance in many experimental circumstances.
authors.affiliation: Departamento de Física-CIOyN, Universidad de Murcia, Murcia, Spain.
authors.forename: A M
authors.initials: AM
authors.lastname: Somoza
authors.forename: M
authors.initials: M
authors.lastname: Ortuño
authors.forename: M
authors.initials: M
authors.lastname: Caravaca
authors.forename: M
authors.initials: M
authors.lastname: Pollak