Entropically stabilized local dipole formation in lead chalcogenides

Emil S. Božin, Christos D. Malliakas, Petros Souvatzis, Thomas Proffen, Nicola A. Spaldin, Mercouri G. Kanatzidis, Simon J.L. Billinge

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199 Citations (Scopus)

Abstract

We report the observation of local structural dipoles that emerge from an undistorted ground state on warming, in contrast to conventional structural phase transitions in which distortions emerge on cooling. Using experimental and theoretical probes of the local structure, we demonstrate this behavior in binary lead chalcogenides, which were believed to adopt the ideal, undistorted rock-salt structure at all temperatures. The behavior is consistent with a simple thermodynamic model in which the emerging dipoles are stabilized in the disordered state at high temperature due to the extra configurational entropy despite the fact that the undistorted structure has lower internal energy. Our findings shed light on the anomalous electronic and thermoelectric properties of the lead chalcogenides. Similar searches may show that the phenomenon is more widespread.

Original languageEnglish
Pages (from-to)1660-1663
Number of pages4
JournalScience
Volume330
Issue number6011
DOIs
Publication statusPublished - Dec 17 2010

ASJC Scopus subject areas

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    Božin, E. S., Malliakas, C. D., Souvatzis, P., Proffen, T., Spaldin, N. A., Kanatzidis, M. G., & Billinge, S. J. L. (2010). Entropically stabilized local dipole formation in lead chalcogenides. Science, 330(6011), 1660-1663. https://doi.org/10.1126/science.1192759