Abstract
We report the in-plane (ρab) and out-of-plane (ρc) resistivities in the 4–800 K range on single crystals of Tl2Ba2CaCu2O8 high-Tc cuprate with Tc = 111 K (ρc/ρab ≈ 1000). ρab(T) exhibits "usual" linear behavior and ρc(T) follows generally metallic-like, positive slope in the 150–400 K temperature range. There is a clear crossover to semiconductor-like behavior close to Tc. However, for the first time in a chainless high-Tc cuprate we observe a crossover above 500 K due to hopping conduction. Under high pressures ( < 15 kbar) the magnitude of ρc strongly decreases, yet the ρc(T) slope does not change. This suggests that the out-of-plane charge transport is governed by the interplane tunneling rate.