Linked Life Data

12540895

Source:http://linkedlifedata.com/resource/pubmed/id/12540895

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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6921
pubmed:dateCreated
2003-1-23
pubmed:abstractText
Quasicrystals have long-range order with symmetries that are incompatible with periodicity, and are often described with reference to a higher-dimensional analogue of a periodic lattice. Within the context of this 'hyperspace' crystallography, lattice dynamics of quasicrystals can be described by a combination of lattice vibrations and atomic fluctuations--phonons and phasons. However, it is difficult to see localized fluctuations in a real-space quasicrystal structure, and so the nature of phason-related fluctuations and their contribution to thermodynamic stability are still not fully understood. Here we use atomic-resolution annular dark-field scanning transmission electron microscopy to map directly the change in thermal diffuse scattering intensity distribution in the quasicrystal, through in situ high-temperature observation of decagonal Al72Ni20Co8. We find that, at 1,100 K, a local anomaly of atomic vibrations becomes significant at specific atomic sites in the structure. The distribution of these localized vibrations is not random but well-correlated, with a quasiperiodic length scale of 2 nm. We are able to explain this feature by an anomalous temperature (Debye-Waller) factor for the Al atoms that sit at the phason-related sites defined within the framework of hyperspace crystallography. The present results therefore provide a direct observation of local thermal vibration anomalies in a solid.
pubmed:language
eng
pubmed:journal
pubmed:status
PubMed-not-MEDLINE
pubmed:month
Jan
pubmed:issn
0028-0836
pubmed:author
pubmed:issnType
Print
pubmed:day
23
pubmed:volume
421
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
347-50
pubmed:dateRevised
2003-11-4
pubmed:year
2003
pubmed:articleTitle
Direct observation of a local thermal vibration anomaly in a quasicrystal.
pubmed:affiliation
Condensed Matter Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA. abe.eiji@nims.go.jp
pubmed:publicationType
Journal Article