Temperature dependence of atomic modulation in the incommensurate composite crystal structure of (Sr2Cu2O3)0.70CuO2, ‘Sr14Cu24O41’

Temperature dependence of atomic modulation in the incommensurate composite crystal structure of (Sr2Cu2O3)0.70CuO2, ‘Sr14Cu24O41’ with two-legged Cu2O3 ladder and edge-shared CuO2 chain has been investigated by single-crystal X-ray diffraction method using centrosymmetric (3 + 1)-dimensional superspace group. The displacive modulations of all constituent atoms at 150 K have been compared with those obtained at room temperature. The hole distribution between the Cu2O3 ladder plane and the one-dimensional CuO2 chain has been considered on the basis of the changes of lattice constants of incommensurate basic structure, the role of the atomic modulation and the interatomic distances between Cu atom in the Cu2O3 and O atom in the CuO2. It is indicated that the small amount of holes doped in the Cu2O3 ladder have been back-transferred to the CuO2 chain and that almost all of the holes in (Sr2Cu2O3)0.70CuO2 are localized in the CuO2 at low temperature.