The Anomalous Optical Conductivity of Metallic La2−xSrxCuO4

Abstract

The in-plane optical conductivity of three metallic La2−x Sr x CuO4 single crystals with 0.10 ≤ x ≤ 0.15 has been studied between 30 and 295 K. Strong peaks in the far-infrared are observed, which cannot be explained by Drude-like models. Their similarity with peaks reported in Cu–O “ladders” with one-dimensional charge-ordering, their extremely low frequency, and their behavior with temperature allows us to conclude that those anomalous features are excitations of charge stripes in the Cu–O planes.