Concentration of charge carriers and anomalous gap parameter in the normal state of high-Tc superconductors

Fermi-Dirac statistics has been utilized by introducing the average ionization energy (E-I) as an additional anomalous energy gap in order to derive the two-dimensional concentration of charge carriers and the phenomenological resistivity model for the superconducting polycrystalline materials. The best fitted values of E-I and the charge carriers' concentration ranges in the vicinity of 4 to 9 meV, and 10(16) m(-2), respectively, for the superconducting single crystal samples and polycrystalline compounds synthesized with various compositions via solid-state reactions. The phenomenological resistivity model is further redefined here based on the gapless nature of charge-carriers' dynamics within the Cu-O-2 planes that corresponds to anomalous Fermi liquid behavior, which is in accordance with the nested Fermi liquid theory. (C) 2002 Elsevier Science B.V. All rights reserved.