6533b825fe1ef96bd12820af
RESEARCH PRODUCT
Electronic correlation effects and the Coulomb gap at finite temperature.
B. SandowAlexander N. IonovK. GloosK. GloosR. RentzschWalter Schirmachersubject
PhysicsCoulomb's constantStrongly Correlated Electrons (cond-mat.str-el)Electronic correlationCondensed matter physicsFOS: Physical sciencesGeneral Physics and AstronomyConductanceCondensed Matter::Mesoscopic Systems and Quantum Hall Effect530Condensed Matter - Strongly Correlated ElectronsElectrical resistivity and conductivityCoulombAtomic physicsSpectroscopyExcitationQuantum tunnellingdescription
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. The tunnel conductance was measured as a function of energy and temperature. At low temperatures, the spectra reveal a minimum at zero bias voltage due to the Coulomb gap. In the temperature range above 1 K the Coulomb gap is filled by thermal excitations. This behavior is reflected in the temperature dependence of the variable-range hopping resitivity measured on the same samples: Up to a few degrees Kelvin the Efros-Shkovskii ln$R \propto T^{-1/2}$ law is obeyed, whereas at higher temperatures deviations from this law are observed, indicating a cross-over to Mott's ln$R \propto T^{-1/4}$ law. The mechanism of this cross-over is different from that considered previously in the literature.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2000-06-29 | Physical review letters |