Electromagnetic response of static and fluctuating stripes in cuprate superconductors

Using infrared spectroscopy, we found that changes in the in-plane charge dynamics attributable to static stripe order in La1.275Nd0.6Sr0.125CuO4 or superconductivity in La1.875Sr0.125CuO4 are confined to energies smaller than 100 cm(-1). 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 cm(-1) characteristic of the pseudogap state in other classes of moderately doped cuprates.