Coupling between superconductivity and structural deformation in La2-xSrxCuO4 (x~0.13).

Capacitance-dilatometer measurements of the anisotropic thermal expansion on a superconducting single crystal of La 2-x Sr x CuO 4 (x∼0.13) show large anomalies at the structural transition from the high-temperature tetragonal to the low-temperature orthorhombic phase followed by smaller anomalies of the opposite sign at the superconducting phase transition. Neutron-diffraction experiments on the same crystal indicate that at T c the tilt of the CuO 6 octahedra related to the structural phase transition is frozen in