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. 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.

arXiv comment3 pages, 3 figures

References in corpus (1)

• Coulomb Gap in a Doped Semiconductor near the Metal-Insulator Transition: Tunneling Experiment and Scaling Ansatz

Cited by in corpus (12)

• The glass transition and the Coulomb gap in electron glasses
• The Memory Effect in Electron Glasses
• The energy gap of intermediate-valent SmB6 studied by point-contact spectroscopy
• Magnetization-Switched Metal-Insulator Transition in a (Ga,Mn)As Tunnel Device
• The metal-insulator transition in disordered solids: How theoretical prejudices influence its characterization. A critical review of analyses of experimental data
• Effect of Increasing Disorder on the Critical Behavior of a Coulomb System
• Nonlinear Hall effect on a disordered lattice
• 2D-Dirac surface states and bulk gap probed via quantum capacitance in a 3D topological insulator
• Numerical observation of a glassy phase in the three-dimensional Coulomb glass
• Tunneling between two semiconductors with localized electrons: Can it reveal the Coulomb gap?
• Specific heat of the Coulomb glass
• Break-Junction Tunneling Spectroscopy for Doped Semiconductors in the Hopping Regime