2000/06/29 by B. Sandow, K. Gloos, R. Rentzsch +3 · 45 citations
Engineering · Materials Science · Physics and Astronomy · #Condensed matter physics #Correlation #Coulomb #Electron #Electronic and Structural Properties of Oxides #Electronic correlation #Physics #Quantum mechanics #Semiconductor materials and devices #ZnO doping and properties #cond-mat.str-el
paper · pdf · doi:10.1103/physrevlett.86.1845
published in Physical Review Letters 86(9), 1845-1848 (American Physical Society) · 3 pages, 3 figures
arxiv created 2000/06/29 · openalex publication_date 2001/02/26 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
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.