1. Atomic-Scale Quantitative Analysis of Lattice Distortions at Interfaces of Two-Dimensionally Sr-Doped La2CuO4 Superlattices
- Author
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Giuliano Gregori, Ute Salzberger, Federico Baiutti, Joachim Maier, Georg Cristiani, Gennady Logvenov, Yi Wang, and Peter A. van Aken
- Subjects
Materials science ,Superlattice ,02 engineering and technology ,01 natural sciences ,Atomic units ,Condensed Matter::Materials Science ,Condensed Matter::Superconductivity ,0103 physical sciences ,Scanning transmission electron microscopy ,transmission electron microscopy ,General Materials Science ,oxide interface ,010306 general physics ,CuO6 octahedron distortion ,Superconductivity ,electron energy loss spectroscopy ,Condensed matter physics ,Electron energy loss spectroscopy ,superconductivity ,Doping ,021001 nanoscience & nanotechnology ,Octahedron ,Transmission electron microscopy ,Condensed Matter::Strongly Correlated Electrons ,0210 nano-technology ,Research Article - Abstract
Using spherical aberration corrected high-resolution and analytical scanning transmission electron microscopy, we have quantitatively studied the lattice distortion and the redistribution of charges in two-dimensionally strontium (Sr)-doped La2CuO4 superlattices, in which single LaO planes are periodically replaced by SrO planes. As shown previously, such structures show Tc up to 35 K as a consequence of local charge accumulation on both sides of the nominal SrO planes position. This is caused by two distinct mechanisms of doping: heterogeneous doping at the downward side of the interface (space-charge effect) and "classical" homogeneous doping at the upward side. The comparative chemical and atomic-structural analyses reveal an interrelation between local CuO6 octahedron distortions, hole spatial distribution, and chemical composition. In particular we observe an anomalous expansion of the apical oxygen-oxygen distance in the heterogeneously doped (space-charge) region, and a substantial shrinkage of the apical oxygen-oxygen distance in the homogeneously doped region. Such findings are interpreted in terms of different Jahn-Teller effects occurring at the two interface sides (downward and upward).
- Published
- 2016