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arXiv · 1204.3003

Reentrant valence transition in EuO at high pressures: beyond the bond-valence model

N. M. Souza-Neto·J. Zhao·E. E. Alp·G. Shen·S. V. Sinogeikin·G. Lapertot·D. Haskel
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Abstract

The pressure-dependent relation between Eu valence and lattice structure in model compound EuO is studied with synchrotron-based x-ray spectroscopic and diffraction techniques. Contrary to expectation, a 7% volume collapse at $\approx$ 45 GPa is accompanied by a reentrant Eu valence transition into a $\emph{lower}$ valence state. In addition to highlighting the need for probing both structure and electronic states directly when valence information is sought in mixed-valent systems, the results also show that widely used bond-valence methods fail to quantitatively describe the complex electronic valence behavior of EuO under pressure.

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N. M. Souza-Neto, J. Zhao, E. E. Alp, G. Shen, S. V. Sinogeikin, G. Lapertot, D. Haskel. 2012-04-13. Reentrant valence transition in EuO at high pressures: beyond the bond-valence model. https://doi.org/10.1103/physrevlett.109.026403

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