International Journal of Advanced Applied Physics Research  (Volume 2 Issue 1)
 Properties of the Coherence Length and Van Hove Singularity in High-Tc Superconductors International Journal of Advanced Applied Physics Research
Pages 19-30


A. Bechlaghem

DOI: http://dx.doi.org/10.15379/2408-977X.2015.02.01.3

Published: 15 June 2015
Abstract
 High- superconductors are characterized by a short coherence length. From the quasi-2D structure of these compounds, we calculate the density of states, the Fermi velocity   and the gap energy. From these parameters, we deduce a formula of the coherence length. We study the effect of the phonon-interaction, the effective mass of carriers and the Coulomb repulsion on the coherence length. We show that when the coupling constant   is in the range 0.060.30 and the effective mass is between 2m0 and 6m0 (m0 is the free electron mass), the values obtained of the coherence length and the gap energy are in a good agreement with experimental results.
Keywords
  Superconductivity, Density of states, Coherence length, Fermi velocity, Fermi energy, Gap energy, Van Hove singularity, Phonon-interaction, Effective mass, Coulomb repulsion.
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