Determination of the Local Lattice Distortions in the Cu${\mathrm{O}}_2$ Plane of L${\mathrm{a}}_{1.85}$S${\mathrm{r}}_{0.15}$Cu${\mathrm{O}}_4$

The measurement of the Cu-O distances by a local and fast probe, polarized Cu K-edge extended x-ray absorption fine structure (EXAFS) in L${\mathrm{a}}_{1.85}$S${\mathrm{r}}_{0.15}$Cu${\mathrm{O}}_4$ crystal shows two different conformations of the Cu${\mathrm{O}}_6$ octahedra below 100 K assigned to two types of stripes with different lattice. This experiment supports a model of “two components” spatially separated in a superlattice of quantum stripes for the anomalous properties of cuprate superconductors.