c-Axis charge dynamics in T* cuprate superconductor

We report on c-axis charge dynamics in T* cuprate superconductors which have two kinds of block layers, rocksalt and fluorite. Multilayer effect has already been obvious by optical measurements that two longitudinal Josephson plasma modes and a transverse optical one appear below Tc in SmLa1−xSrxCuO4−δ (SLSCO) by forming Josephson superlattice as S/I1/S/I2/S along c-axis. The phenomenon can be explained as also charging effect on CuO2 plane and is seen also in bilayer cuprates such as YBCO and BISCCO. Here we discuss the universality on penetration depth λc against dc c-axis conductivity σc. In general, λc is determined by a longitudinal Josephson plasma mode ωp as λc = 1/2πωp in case of single junction. It is well-known that the penetration depth determined by the Josephson plasma is almost scaled with σc in high-Tc cuprates. We show that the universality is valid for even T* cuprates which has two different Josephson junctions and discuss an intimate correlation among λc, anisotropy and charging effect.