Effects of rare-earth ion size on the stability of the coherent Jahn-Teller distortions in undoped perovskite manganites

Document Type

Article

Publication Date

11-12-2012

Abstract

We present a theoretical study on the relation between the size of the rare earth ion, often known as chemical pressure, and the stability of the coherent Jahn-Teller distortions in undoped perovskite manganites. Using a Keating model expressed in terms of atomic scale symmetry modes for a simplified two-dimensional model, we show that there exists a coupling between the uniform shear distortion and the staggered buckling distortion within the Jahn-Teller energy term. It is found that this coupling provides a mechanism by which the coherent Jahn-Teller distortion is more stabilized by a smaller rare earth ion. We analyze the appearance of the uniform shear distortion below the Jahn-Teller ordering temperature, estimate the Jahn-Teller ordering temperature and its variation among LaMnO 3, PrMnO 3, and NdMnO 3, and obtain the relations between distortions. We find good agreement between theoretical results and experimental data. © 2012 American Physical Society.

Identifier

84870011227 (Scopus)

Publication Title

Physical Review B Condensed Matter and Materials Physics

External Full Text Location

https://doi.org/10.1103/PhysRevB.86.184106

e-ISSN

1550235X

ISSN

10980121

Issue

18

Volume

86

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