| Tilt and acoustic instabilities in ABX4, A2BX4 and ABX3 perovskite structure types: their role in the incommensurate phases of the organic-inorganic perovskites. | |
| | |
MedLine Citation:
|
PMID: 16306669 Owner: NLM Status: PubMed-not-MEDLINE |
Abstract/OtherAbstract:
|
An examination of the tilt modes and other low-frequency modes is made for an isolated, untilted perovskite layer, which maps very simply to the ABX4 perovskites. A sheet of pure tilts exists at the Brillouin Zone boundary at {xi, (1/2), zeta}. An instability is also found at all wavevectors which can be described as continuously varying from pure tilts to pure layer displacements as a function of the wavevector. Analysis is extended by considering the stacking of layers in the I-centered A2BX4-layer perovskites. The effect of freezing in the commensurate tilt required to generate the Cmca tilt system, pertinent to the modulated phases of propylammonium salts, is examined. The zero-frequency modes are restricted to two planes in the Brillouin Zone. All of the observed wavevectors associated with modulated phases, and the commensurately tilted propylammonium tetrachlorocadmate, are consistent with this calculation. The effect of full three-dimensional connectivity is briefly reviewed for the true ABX3 perovskites. While pure tilt incommensurates appear to be hypothetically possible, they do not appear to have been observed to date. |
| | |
Authors:
|
Ian Peter Swainson |
Related Documents
:
|
9401459 - The effect of shape and location on temporal masking of spatial vibrotactile patterns. 22315419 - Insights from past millennia into climatic impacts on human health and survival. 17080999 - Biosynthesis of 13-desmethyl spirolide c by the dinoflagellate alexandrium ostenfeldii. 22715989 - Developmental origins of non-communicable disease: implications for research and public... 17253819 - Single-isomer iodochlorination of alkynes and chlorination of alkenes using tetrabutyla... 10115479 - Changes in the hungarian health system. 16835189 - It ain't necessarily so: the electronic health record and the unlikely prospect of redu... 2403939 - Controversies in occlusion. 18164459 - Evidence-informed management of chronic low back pain with lumbar stabilization exercises. |
Publication Detail:
|
Type: Journal Article Date: 2005-11-14 |
Journal Detail:
|
Title: Acta crystallographica. Section B, Structural science Volume: 61 ISSN: 0108-7681 ISO Abbreviation: Acta Crystallogr., B Publication Date: 2005 Dec |
Date Detail:
|
Created Date: 2005-11-24 Completed Date: 2006-12-05 Revised Date: 2007-07-24 |
Medline Journal Info:
|
Nlm Unique ID: 8403252 Medline TA: Acta Crystallogr B Country: Denmark |
Other Details:
|
Languages: eng Pagination: 616-26 Citation Subset: - |
Affiliation:
|
Canadian Neutron Beam Centre, National Research Council of Canada, Chalk River Laboratories, Chalk River, Ontario, Canada K0J 1J0. ian.swainson@nrc.gc.ca |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
|
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: X-ray diffraction study for one-dimensional ionic conductors K(x)(Ga(1 - y)Al(y))(2 + x)Ti(2 - x)O(7...
Next Document: Second-degree twinning and dynamic disorder in the crystal structure of deca-dodecasil 3R.