Local structure of superconducting (La,Sr)2CuO4 under strain: Microscopic mechanism of strain-induced Tc variation

High-quality polarized x-ray absorption spectroscopy data for (La,Sr)2CuO4 thin-film single crystals reveal strain-dependent local disorder (in the oxygen radial distribution) that correlates with the superconducting critical temperature. The temperature-dependent in-plane oxygen displacement shows that local lattice distortion strongly depends on strain, i.e., the biaxial tensile strain develops domains with the bond-stretching-type local distortion which is weakened by the compressive strain. We suggest that the two-dimensional strain modifies electronic inhomogeneity that influences the superconducting critical temperature through superfluid density, rather than band structure effects.