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Tunneling Spectroscopy near the Metal–Insulator Transition
Author(s) -
Sandow B.,
Gloos K.,
Naidyuk Yu.,
Naidyuk Yu.,
Rentzsch R.,
Ionov A. N.
Publication year - 1998
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/(sici)1521-3951(199801)205:1<281::aid-pssb281>3.0.co;2-#
Subject(s) - quantum tunnelling , spectroscopy , materials science , scanning tunneling spectroscopy , transition metal , optoelectronics , condensed matter physics , nanotechnology , chemical physics , chemistry , physics , quantum mechanics , biochemistry , catalysis
Barely insulating disordered solids have the electronic states localized. Analyzing the density of states (DOS) by taking into account Coulomb correlations results in a particularity both on the metallic and on the insulating side of the disorder‐driven metal–insulator transition (MIT): Coulomb interactions deplete the DOS near the Fermi energy E F . Efros and Shklovskii [1] pointed out that for solids on the insulating side of the MIT at T = 0, long‐range Coulomb interactions lead to the formation of a Coulomb gap. The DOS decreases then with a power law when the energy approaches E F . To investigate the density of states at E F of n‐type germanium we tried tunneling spectroscopy using mechanically‐controllable break junctions [2] down to 100 mK. The tunneling conductance was found to depend strongly on energy and temperature. We analyze these experiments together with the bulk electrical resistivity.