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.