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Ferroelectricity and isotope effects in hydrogen-bonded KDP crystals

S. Koval·J. Kohanoff·R. L. Migoni·E. Tosatti
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Abstract

Based on an accurate first principles description of the energetics in H-bonded KDP, we conduct a first study of nuclear quantum effects and of the changes brought about by deuteration. Cluster tunneling involving also heavy ions is allowed, the main effect of deuteration being a depletion of the proton probability density at the O-H-O bridge center, which in turn weakens its proton-mediated covalent bonding. The ensuing lattice expansion couples selfconsistently with the proton off-centering, thus explaining both the giant isotope effect, and its close connection with geometrical effects.

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S. Koval, J. Kohanoff, R. L. Migoni, E. Tosatti. 2002-06-03. Ferroelectricity and isotope effects in hydrogen-bonded KDP crystals. https://doi.org/10.1103/physrevlett.89.187602

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