c-axis resistance peak above the critical temperature in layered superconductors

The possibility fully describing the behavior of transverse resistivity rho(c) in cuprate superconductors exclusively in terms of some recently proposed normal-state models is discussed. It is shown that these models do not give a completely satisfactory description of the apparent singularity in rho(c) at the critical temperature in Bi2Sr2CaCu2O8+x, and that they fail to describe data concerning a lower-T-c cuprate superconductor as Bi2Sr2CuO6+x (T-c congruent to 15 K). It is argued that these difficulties cannot be overcome considering the normal-state contribution to rho(c) only. The role of the density of states fluctuations in the behavior of rho(c) just about the transition temperature is recalled. It is shown that, laking into account this contribution, it is possible to dramatically simplify the description of the the normal-state transverse resistivity, This can give important hints for the understanding of the transverse electrical transport properties of these materials.