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Coulomb Gap in n‐ZnSe and Its Critical Behaviour in the Region of the Metal–Dielectric Transition
Author(s) -
Kasiyan V. A.,
Nedeoglo D. D.,
Simashkevich A. V.,
Timchenko I. N.
Publication year - 1990
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/pssb.2221580129
Subject(s) - condensed matter physics , coulomb , dielectric , impurity , materials science , scaling , electrical resistivity and conductivity , physics , quantum mechanics , geometry , mathematics , electron , optoelectronics
In the temperature interval from 1.65 to 300 K the conductivity of n‐ZnSe crystals on the dielectric side of the metal‐dielectric transition (MD) induced by a change of the compensation from 0.39 to 0.98 or of the concentration of the donor impurity from 2 × 10 16 cm −3 to 2 × 10 18 cm −3 is studied. It is established that at sufficently low temperatures on the dielectric side of the MD transition Q ∼ exp ( T o T ) 1/2 which is indicative of the presence of a parabolic Coulomb gap at the Fermi level. The main parameters of the Coulomb gap: width, depth, density of states are determined and their concentration dependences also investigated. It is shown that the compensation blurs the MD transition and shifts it to the region of large critical concentrations. The critical behaviour of the Coulomb gap parameters within the scope of the scaling theory and the dynamics of its collapse at the transition are described.