A search for extra lattice distortions associated with the superconductivity and the charge inhomogeneities in the high-Tc La1.85Sr0.15CuO4 system Original Research Article

Precise measurements of the temperature-dependent lattice parameters in a single crystal of La1.85Sr0.15CuO4 are made by X-ray bond method and analyzed comparing the normal thermal expansion term, proportional to T4. A spontaneous lattice contraction of about 2.3×10−5 Å was found in the ab-plane, while along the c-axis a small expansion of about 1.5×10−5 Å was observed below the superconducting transition temperature of the system, showing some correlation between the structure and the high-Tc superconductivity. A careful search has been made for existence of any extra lattice distortion above the Tc, that might be associated with the stripe inhomogeneities in the title system, however, within the experimental sensitivity we could not find such distortions.