Study of the B1-B2 transition in colloidal clusters

Davide Bochicchio 1, 2 Arnaud Videcoq 1 R. Ferrando 2, *
* Auteur correspondant
1 SPCTS-AXE1 - Axe 1 : procédés céramiques
SPCTS - Science des Procédés Céramiques et de Traitements de Surface
Abstract : The possible mechanisms for the B1 (NaCl-type) to B2 (CsCl-type) transition in crystalline colloidal clusters of equally sized particles are studied by means of two computational techniques: metadynamics and nudged elastic band calculations. The system is modelled by a screened Coulomb potential. Different interaction ranges are considered. The transition from a perfect NaCl cubic cluster to a full CsCl cluster is forced by metadynamics, revealing a transition path with intermediate metastable configurations in which planes are shifted one by one. The presence of metastable configurations in the transition path, corresponding to a certain number of NaCl planes turned into CsCl, has clear analogies with the known Hyde and O'Keeffe mechanism for ionic crystals, with some important differences due to finite-size effects. These comprise the fact that the transition starts by shifting a surface plane by means of a row-by-row mechanism that has no analog in bulk crystals. The energy barriers between the local minima in the transition path are calculated, showing that the barriers strongly depend on the screening length, in such a way that the B1 metastable phase can have very long lifetimes when the interaction is sufficiently long-ranged
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https://hal-unilim.archives-ouvertes.fr/hal-01116001
Contributeur : Fabrice Rossignol <>
Soumis le : jeudi 12 février 2015 - 12:09:58
Dernière modification le : mercredi 14 février 2018 - 16:02:06

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Davide Bochicchio, Arnaud Videcoq, R. Ferrando. Study of the B1-B2 transition in colloidal clusters. Journal of the Chemical Society, Faraday Transactions 2: Molecular and Chemical Physics, The Royal Society of Chemistry, 2014, 140 (2), pp.1-7. ⟨10.1063/1.4861049⟩. ⟨hal-01116001⟩

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