Normal-state c-axis transport in Bi2Sr2CaCu2O8+delta: Interlayer tunneling and thermally activated dissipation

We systematically investigate the effect of doping on the temperature dependence of the c-axis resistivity in Bi2Sr2CaCu2O8+delta. We present simultaneous measurements of the resistivity tensor components rho(c) and rho(ab) at different doping from the underdoped to the overdoped regime. The c-axis resistivity behaviors as a function of temperature are interpreted, in the normal state (T>T*), through a single phenomenological model based on the existence of two energy barriers with different heights and widths. Two complementary processes are considered for each barrier: incoherent tunneling and thermal activation. The resistive measurements at different doping are well fitted with a small number of free parameters with well defined physical meanings. The analysis of the behaviors of the fitting parameters as a function of doping gives support and consistency to the two-barrier model.