Anomalous Expansion of the Copper-Apical Oxygen Distance in Superconducting La$_{2}$CuO$_{4}$ - La$_{1.55}$Sr$_{0.45}$CuO$_{4}$ Bilayers

Hua Zhou; Yizhak Yacoby; Ron Pindak; Vladimir Butko; Gennady Logvenov; Ivan Bozovic

doi:10.1073/pnas.0914702107

paper

Anomalous Expansion of the Copper-Apical Oxygen Distance in Superconducting La $_{2}$ CuO $_{4}$ - La $_{1.55}$ Sr $_{0.45}$ CuO $_{4}$ Bilayers

arXiv:0903.2097 · doi:10.1073/pnas.0914702107

Abstract

We have introduced an improved X-ray phase-retrieval method with unprecedented speed of convergence and precision, and used it to determine with sub-Ångstrom resolution the complete atomic structure of an ultrathin superconducting bilayer film, composed of La $_{1.55}$ Sr $_{0.45}$ CuO $_{4}$ and La $_{2}$ CuO $_{4}$ neither of which is superconducting by itself. The results show that phase-retrieval diffraction techniques enable accurate measurement of structural modifications in near-surface layers, which may be critically important for elucidation of surface-sensitive experiments. Specifically we find that close to the sample surface the unit cell size remains constant while the copper-apical oxygen distance shows a dramatic increase, by as much as 0.45 Å. The apical oxygen displacement is known to have a profound effect on the superconducting transition temperature.

4 pages, 4 figures, LaTex; typos corrected, the status of Ref. 31 updated

Anomalous Expansion of the Copper-Apical Oxygen Distance in Superconducting La $_{2}$ CuO $_{4}$ - La $_{1.55}$ Sr $_{0.45}$ CuO $_{4}$ Bilayers

Abstract

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Anomalous Expansion of the Copper-Apical Oxygen Distance in Superconducting La2​CuO4​ - La1.55​Sr0.45​CuO4​ Bilayers

Abstract

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Cited by in corpus (10)

Anomalous Expansion of the Copper-Apical Oxygen Distance in Superconducting La $_{2}$ CuO $_{4}$ - La $_{1.55}$ Sr $_{0.45}$ CuO $_{4}$ Bilayers