Temperature-Induced Smearing of the Coulomb Gap: Experiment and Computer Simulation

Abstract

We present the first verification of the theoretically predicted effect of temperature-induced smearing of the Coulomb gap. Measurements of the variable-range-hopping conductivity (VRH) in samples of ion-implanted $\mathrm{Si}:\mathrm{As}$ and computer simulation are used to study the density of states (DOS) near the Fermi level (FL) in the impurity band. The VRH is determined by the DOS integrated over some energy range that depends on temperature $T$ and on the magnetic field $B$. Using the interplay between $T$ and $B$ we find that the DOS in the vicinity of the FL increases with increasing $T$.