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Dynamics of Polar Surfaces on Ceria Nanoparticles Observed In Situ with Single‐Atom Resolution
Author(s) -
Möbus Günter,
Saghi Zineb,
Sayle Dean C.,
Bhatta Umananda M.,
Stringfellow Andrew,
Sayle Thi X.T.
Publication year - 2011
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201002135
Subject(s) - materials science , atom (system on chip) , polar , dipole , molecular dynamics , molecular physics , resolution (logic) , chemical physics , cerium , nanoparticle , atomic physics , nanotechnology , physics , chemistry , computational chemistry , astronomy , artificial intelligence , computer science , metallurgy , embedded system , quantum mechanics
Atomic hopping processes on ceria nanoparticle surfaces are observed by in situ phase contrast high‐resolution electron microscopy with an aberration‐corrected imaging lens. It is shown that single‐atom resolution is possible, and single‐atom dynamics for cerium are observable. Discrete changes in contrast and discrete positional changes of contrast maxima can be safely interpreted as visual fingerprints of atomic displacements. Both single‐atom movements and spontaneous sequential relocations of entire atomic rows are observed. Exclusive occurence of the effect on {100} type facets indicates polar dipole field mediated atomic rearrangements, while {111} facets are found to be stable. Molecular modelling confirms that the relocations follow genuine pathways involving partially occupied oxygen‐terminated surfaces, by means of temperature induced fluctuations. A series of images tracks the detailed atomic motions over a time of 120 s and quantifies the ratio of reversible atom hopping versus atom ablation.