The density of states in the Coulomb gap
- 27 September 1985
- journal article
- research article
- Published by Taylor & Francis in Philosophical Magazine Part B
- Vol. 52 (3) , 511-520
- https://doi.org/10.1080/13642818508240620
Abstract
A new bound on the density of single-particle states N 1(E) in the Coulomb gap is derived. This is exponential in three-dimensional systems, A(E/E 0)−3/2 × exp{-(E/E 0)−1)}, and a power-law in two dimensions. The method, following the suggestion of Efros and Shklovskii (1975), is to consider the relaxation around a particle added to the ground state. The electric field of this extra charge induces electron-hole transitions in the surroundings, which lower the total energy of the excitation. The energy must not become negative, however; so the distribution of relaxation energies, which I have calculated using Chandraskehar's method, provides a bound on N 1(E). The calculation also shows how the Coulomb gap for ‘electronic polarons’ narrows rapidly as the region of relaxation included in the excitation increases.Keywords
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