Using infrared spectroscopy, we found that changes in the in-plane charge dynamics attributable to static stripe order in ${\mathrm{La}}_{1.275}{\mathrm{Nd}}_{0.6}{\mathrm{Sr}}_{0.125}{\mathrm{CuO}}_4$ or superconductivity in ${\mathrm{La}}_{1.875}{\mathrm{Sr}}_{0.125}{\mathrm{CuO}}_4$ are confined to energies smaller than $100{\mathrm{cm}}^{-1\mathrm{}}$. An absorption peak in the low- $\omega$ conductivity of the Nd-doped compound is suggestive of localization effects due to the reduced dimensionality of static charge stripes. Neither superconductivity nor static stripe ordering has a noticeable effect on the depression of the scattering rate at $\omega <1000\mathrm{}{\mathrm{cm}}^{-1\mathrm{}}$ characteristic of the pseudogap state in other classes of moderately doped cuprates.

• Received 24 August 2001

DOI:https://doi.org/10.1103/PhysRevLett.88.147003