Possible Mechanism of Semiconductive Temperature Dependence ofc-Axis Resistivity in the Normal State of High-TcSuperconductors: Renormalization Effect of Fermi Surface by Antiferromagnetic Spin Fluctuations

We propose a mechanism of the semiconductive temperature dependence of the c -axis resistivity (ρ c ) in the normal state of high- T c superconductors. We show that antiferromagnetic spin fluctuations in the CuO 2 -layer affect the temperature dependence of the Fermi surface shape and that they decrease (increase) the conductive carrier density (band mass) in the c -direction. Thus, when this effect dominates the temperature dependence of ρ c , ρ c increases at low temperatures. On the other hand, in the in-plane direction, the AF spin fluctuations do not affect the carrier density while they decrease the so-called k -mass at low temperatures. As a consequence, taking into account the damping rate which is caused by the electron-electron interaction, we obtain the in-plane resistivity (ρ ab ) which decreases with decreasing temperature. Thus, the present mechanism can explain the semiconductive temperature dependence of ρ c satisfying the metallic behavior of ρ ab .