title: Electronic correlation effects and the Coulomb gap at finite temperature.
abstract: We have investigated the effect of the long-range Coulomb interaction on the one-particle excitation spectrum of n-type germanium, using tunneling spectroscopy on mechanically controllable break junctions. At low temperatures, the tunnel conductance shows a minimum at zero bias voltage due to the Coulomb gap. Above 1 K, the gap is filled by thermal excitations. This behavior is reflected in the variable-range hopping resistivity measured on the same samples: up to a few degrees Kelvin the Efros-Shklovskii lnR infinity T(-1/2) law is obeyed, whereas at higher temperatures deviations from this law occur. The type of crossover differs from that considered previously in the literature.
authors: Institut für Experimentalphysik, Freie Universität Berlin, Germany.
authors: B
authors: B
authors: Sandow
authors: K
authors: K
authors: Gloos
authors: R
authors: R
authors: Rentzsch
authors: A N
authors: AN
authors: Ionov
authors: W
authors: W
authors: Schirmacher