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Updated: Apr 12, 2026
Epitaxial Growth of Perovskite Strontium Titanate on Germanium via Atomic Layer Deposition
Published on: July 26, 2016
Crystal structure of SrGeO3 in the high-pressure perovskite-type phase
Akihiko Nakatsuka1, Hiroshi Arima2, Osamu Ohtaka3
1Graduate School of Science and Engineering, Yamaguchi University, Ube 755-8611, Japan.
Abstract:
Single crystals of the SrGeO3 (strontium germanium trioxide) high-pressure phase have been synthesized successfully at 6 GPa and 1223 K. The compound crystallizes with the ideal cubic perovskite-type structure (space group Pm-3m), which consists of a network of corner-linked regular GeO6 octa-hedra (point-group symmetry m-3m), with the larger Sr atoms located at the centers of cavities in the form of SrO12 cubocta-hedra (point-group symmetry m-3m) in the network. The degrees of covalencies included in the Sr-O and the Ge-O bonds calculated from bond valences are 20.4 and 48.9%, respectively. Thus, the Ge-O bond of the GeO6 octa-hedron in the SrGeO3 perovskite has a strong covalency, comparable to those of the Si-O bonds of the SiO4 tetra-hedra in silicates with about 50% covalency. The thermal vibrations of the O atoms in the title compound are remarkably suppressed in the directions of the Ge-O bonds. This anisotropy ranks among the largest observed in stoichiometric cubic perovskites.
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