Premium
Does a magnetic field suppress the Coulomb gap?
Author(s) -
Sandow B.,
Gloos K.,
Rentzsch R.,
Ionov A.N.,
Schirmacher W.
Publication year - 1999
Publication title -
annalen der physik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.009
H-Index - 68
eISSN - 1521-3889
pISSN - 0003-3804
DOI - 10.1002/(sici)1521-3889(199911)8:7/9<711::aid-andp711>3.0.co;2-a
Subject(s) - condensed matter physics , quantum tunnelling , conductance , physics , coulomb , density of states , magnetic field , fermi level , electron , band gap , fermi energy , quantum mechanics
We used electron‐tunnelling spectroscopy to investigate the Coulomb correlation in n ‐ type Germanium. The dopant concentration was smaller than the critical concentration for the metal‐insulator (Anderson) transition. The tunnelling conductance, which probes the electronic density of states, was found to depend strongly on both voltage and temperature. At low temperatures it shows a conductance minimum at the Fermi energy as expected for the Coulomb correlation gap. Applying a magnetic field up to B = 4 T at T = 0.1 K reduces the magnitude of the tunneling conductance, but does not significantly change the shape of the spectra. At higher fields, the conductance minimum disappears, suggesting a suppression of the Coulomb gap. This could be due to the field‐induced confinement of the electron wave functions, that strongly reduces the overlap between the localized electron states.