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arXiv · 1407.0339

Ferroelectric properties of charge-ordered alpha-(BEDT-TTF)2I3

P. Lunkenheimer·B. Hartmann·M. Lang·J. Müller·D. Schweitzer·S. Krohns·A. Loidl
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Abstract

A detailed investigation of the out-of-plane electrical properties of charge-ordered alpha-(BEDT-TTF)2I3 provides clear evidence for ferroelectricity. Similar to multiferroic alpha-(BEDT-TTF)2Cu[N(CN)2]Cl, the polar order in this material is ascribed to the occurrence of bond- and site-centered charge order. Dielectric response typical for relaxor ferroelectricity is found deep in the charge-ordered state. We suggest an explanation in terms of the existence of polar and nonpolar stacks of the organic molecules in this material, preventing long-range ferroelectricity. The results are discussed in relation to the formation or absence of electronic polar order in related charge-transfer salts.

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P. Lunkenheimer, B. Hartmann, M. Lang, J. Müller, D. Schweitzer, S. Krohns, A. Loidl. 2014-07-01. Ferroelectric properties of charge-ordered alpha-(BEDT-TTF)2I3. https://doi.org/10.1103/physrevb.91.245132

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