Effect of reduction in the density of states on fluctuation conductivity in Bi 2Sr 2CaCu 2O 8+ x single crystals

Abstract

The in-plane ( ρ ab ) and out-of-plane ( ρ c ) resistivities of BSCCO single crystals have been measured by six terminals technique. The ρ ab and ρ c are well described by the fluctuation theory developed by Dorin et al. The main effect of these fluctuations is to cause a reduction in the quasi-particle density of states (DOS), leading to a negative contribution in the fluctuation conductivity Lawrence–Doniach (LD) and Maki–Thompson (MT) contributions. We have analyzed paraconductivity by adding this DOS contribution to LD and MT contributions. The analysis shows that approaches based on the conventional LD model alone cannot explain the paraconductivity along ab-plane and c-axis, even when the MT contribution is included.