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TT: Fachverband Tiefe Temperaturen
TT 28: Transport - Poster Session
TT 28.51: Poster
Donnerstag, 29. März 2007, 14:00–17:45, Poster A
Break junction tunnel spectroscopy in the hopping regime — •Barbara Sandow1, Dirk Brossell1, Olaf Bleibaum2, and Walter Schirmacher3 — 1Institut für Experimentalphysik, Freie Universität Berlin — 2Institut für Theoretische Physik, Otto-von-Gericke Universität Magdeburg — 3Physic Department E13, Technische Universität München
Break junction tunnel spectroscopy is a tradtional method for investigating the electronic structure of solids. In weakly doped semiconductors in the hopping regime the spectra cannot be interpreted by means of Bardeen's [1] theory, because it is based on a metallic conduction mechanism. We have formulated a new ansatz [2] for the tunnel current in the hopping regime. Using our new theory we are able to interpret data which exhibit the Coulomb gap in a satisfactory way. The dependence of the gap width on temperature and carrier concentration is discussed in terms of current theories of the Coulomb gap.
1 J. Bardeen, Phys. Rev. Lett. 6, 75 (1961) 2 O. Bleibaum, B. Sandow, W. Schirmacher, Phys. Rev. B 70, 045308-1 (2004)