1. Epitaxial Stabilization of SrCu3O4 with Infinite Cu3/2O2 Layers
- Author
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Hiroshi Takatsu, Naoya Yamashina, Morito Namba, Kazuhiko Kuroki, Takahito Terashima, Masayuki Ochi, and Hiroshi Kageyama
- Subjects
Superconductivity ,Condensed Matter - Materials Science ,Valence (chemistry) ,Condensed matter physics ,010405 organic chemistry ,Chemistry ,Materials Science (cond-mat.mtrl-sci) ,FOS: Physical sciences ,010402 general chemistry ,Epitaxy ,01 natural sciences ,0104 chemical sciences ,Inorganic Chemistry ,Octahedron ,X-ray photoelectron spectroscopy ,Electrical resistivity and conductivity ,Metastability ,Physical and Theoretical Chemistry ,Molecular beam epitaxy - Abstract
We report the epitaxial thin film synthesis of SrCu$_3$O$_4$ with infinitely stacked Cu$_3$O$_4$ layers composed of edge-sharing CuO$_4$ square-planes, using molecular beam epitaxy. Experimental and theoretical characterizations showed that this material is a metastable phase that can exist by applying tensile biaxial strain from the (001)-SrTiO$_3$ substrate. SrCu$_3$O$_4$ shows an insulating electrical resistivity in accordance with the Cu$^{2+}$ valence state revealed X-ray photoelectron spectroscopy. First-principles calculations also indicated that the unoccupied $d_{3z^2-r^2}$ band becomes substantially stabilized owing to the absence of apical anions, in contrast to $A_2$Cu$_3$O$_4$Cl$_2$ ($A = $Sr, Ba) with an $A_2$Cl$_2$ block layer and therefore a trans-CuO$_4$Cl$_2$ octahedron. These results suggest that SrCu$_3$O$_4$ is a suitable parent material for electron-doped superconductivity based on the Cu$_3$O$_4$ plane., 1 column, 22 pages, 6 figures, Supporting Information
- Published
- 2020