An Investigation of c-axis Charge Transport in Double Layer Cuprate

In this book we have studied the out-of-plane, c-axis resistivity, ρc(T), of Ca doped Y(Ca)Ba2Cu3O7-δ high-Tc superconductors (cuprates). Our aim was to model the c-axis resistivity by considering the full impact of the pseudogap (PG) in the electronic density of states (EDOS) in cuprates and to understand the role of the k (wave vector) on hopping integral along the c-direction. We have used the formalism developed by T. Xiang et al. (Phys. Rev. B 73, 134510 (2006)) to fit the experimental resistivity data for high quality single crystals of Y(Ca)Ba2Cu3O7-δ over a wide range of hole content in the CuO2 plane, p. We have found systematic behavior of maximum pseudogap energy scale, Δ, with doping. It is also found that the coefficient, αc, determining the extent of linearity of ρc(T) is also strongly p-dependent. The analysis also reveals that the formalism developed by T. Xiang et al., fails to produce reliable estimates of Δ and αc for the overdoped compounds. The extrapolated values of Δ(p) tends to vanish at p ~ 0.2. We have discussed the various features of the analysis in detail in this monograph.