Role of the inner copper oxide plane in interlayer Josephson effects in multilayered cuprate superconductors

We find systematic signatures suggesting a different superconducting nature for a triple-layered cuprate Bi2Sr2Ca2Cu3O10+δ with respect to a double layer through the properties of intrinsic Josephson junctions (IJJs). Our measurements on the current-voltage characteristics reveal that the c-axis maximum Josephson current density is sensitive to the superfluid density in outer planes while the critical temperature and the superconducting gap remain unaffected. Switching dynamics of stacked IJJs exhibit that the fluctuation in the gauge-invariant phase difference of an IJJ implies that the inner plane completely shields the capacitive coupling between adjacent IJJs, which is essential for mono- and bilayered cuprates.