Dynamical stripe structure in La$_{2-x}$Sr$_x$CuO$_4$ observed by Raman scattering
The dynamical stripe structure relating to the "1/8 problem" was investigated in La$_{2-x}$Sr$_x$CuO$_4$ utilizing the high frequency response of Raman scattering. The split of the two-magnon peak due to the formation of the stripe structure was observed at whole Sr concentration region from $x=0.035$ to 0.25 at low temperatures. Especially clear split was observed at low carrier concentration region $x=0.035 - 0.06$ and at $x \sim 1/8$. The onset temperatures of these stripe structures are as high as 300-350 K, which are much higher than the temperatures measured by slow response probes.