Thermal and Nuclear Quantum Effects at the Antiferroelectric to Paraelectric Phase Transition in KOH and KOD Crystals
| Autor: | Michele Ceotto, Philippe Depondt, Fabio Finocchi, Erika Fallacara, Simon Huppert |
|---|---|
| Přispěvatelé: | Institut des Nanosciences de Paris (INSP), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Oxydes en basses dimensions (INSP-E9), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS) |
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Phase transition
Materials science Condensed matter physics 02 engineering and technology Dielectric 021001 nanoscience & nanotechnology 01 natural sciences Article Surfaces Coatings and Films Electronic Optical and Magnetic Materials Condensed Matter::Materials Science General Energy 0103 physical sciences Thermal Antiferroelectricity Physical and Theoretical Chemistry [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat] 010306 general physics 0210 nano-technology ComputingMilieux_MISCELLANEOUS |
| Zdroj: | Journal of Physical Chemistry C Journal of Physical Chemistry C, American Chemical Society, 2021, 125 (40), pp.22328-22334. ⟨10.1021/acs.jpcc.1c06953⟩ The Journal of Physical Chemistry. C, Nanomaterials and Interfaces |
| ISSN: | 1932-7447 1932-7455 |
| Popis: | Crystalline KOH undergoes an antiferroelectric (AFE) proton ordering phase transition at low temperatures, which results in a monoclinic bilayer structure held together by a network of weak hydrogen bonds (HBs). The Curie temperature shifts up when the compound is deuterated, an effect that classical MD is not able to catch. For deeper insights into the transition mechanism, we carry out ab initio MD simulations of KOH and KOD crystals by including quantum effects on the nuclei through Feynman path integrals. The geometric isotope effect and the evolution of the lattice parameters with temperature agree with the experimental data, while the purely classical description is not appropriate. Our results show that deuteration strengthens the HBs in the low-T AFE ordered phase. The transition is characterized by the flipping of OH/OD groups along a bending mode. Above the transition, the system is driven into a dynamical disordered paraelectric phase. |
| Databáze: | OpenAIRE |
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