Issue 20, 2019

Negative thermal expansion in high pressure layered perovskite Ca2GeO4

Abstract

We report the high pressure synthesis of a layered perovskite Ca2GeO4 which is found to have the Ruddlesden–Popper structure with I41/acd symmetry. Consonant with our recent predictions [Ablitt et al., npj Comput. Mater., 2017, 3, 44], the phase displays pronounced uniaxial negative thermal expansion over a large temperature range. Negative thermal expansion that persists over a large temperature range is very unusual in the perovskite structure, and its occurrence in this instance can be understood to arise due to both soft lattice vibrations associated with a phase competition and the unusually compliant nature of this structure, which effectively couples thermal expansion in the layer plane to lattice contractions perpendicular to the layering direction via a “corkscrew” mechanism.

Graphical abstract: Negative thermal expansion in high pressure layered perovskite Ca2GeO4

  • This article is part of the themed collection: Perovskites

Supplementary files

Article information

Article type
Communication
Submitted
03 Dec. 2018
Accepted
23 Janv. 2019
First published
20 Febr. 2019
This article is Open Access
Creative Commons BY license

Chem. Commun., 2019,55, 2984-2987

Negative thermal expansion in high pressure layered perovskite Ca2GeO4

W. Chen, C. Ablitt, N. C. Bristowe, A. A. Mostofi, T. Saito, Y. Shimakawa and M. S. Senn, Chem. Commun., 2019, 55, 2984 DOI: 10.1039/C8CC09614G

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