Temperature dependence of the c-axis resistivity of high-$T_c$ layered oxides

Electrical transport along the c axis of high-$T_c$ layered oxides is pictured as a coherent interplanar tunneling between neighboring layers blocked by repeated intraplanar incoherent scatterings. This gives the same temperature dependence for the c-axis resistivity as that for the in-plane resistivity. Additional temperature dependence can arise from the temperature-dependent renormalization of the tunneling matrix element by an ohmic coupling to adiabatic phonons because of the large effective electron mass along the c axis. Our calculation is consistent with recent experimental results on single crystals, and makes some definite predictions that can be put to test