c-axis optical response in the static stripe ordered phase of the cuprates

The c-axis far-infrared reflectivity spectra in the superconducting state were investigated for La1.85-yNdySr0.15CuO4. The Josephson plasma edge rapidly shifts towards lower frequency with increasing y, and almost disappears when y exceeds a critical value (y(c) approximate to 0.12) above which the low-temperature-tetragonal (LTT) deformation switches on, stabilizing the spin/charge ordered stripe phase. In the vicinity of y(c), a normal state reentrant behavior was observed with lowering temperature below T-c. This clearly demonstrates that the static stripe order pinned by the LTT distortion suppresses the interlayer phase coherence.