Electronic Resource
College Park, Md.
:
American Institute of Physics (AIP)
The Journal of Chemical Physics
114 (2001), S. 2395-2400
ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
Using the local-density approximation, and calculating the Hellmann–Feynman forces, the stability of the perovskite-like structures of CaTiO3 have been studied by applying the direct method and deriving the phonon dispersion relations. The cubic Pm3¯m phase shows dispersionless soft phonon branch spreading from R to M points of the cubic Brillouin zone. Low-symmetry phase I4/mcm can be considered as a result of the soft mode condensation at R point. The experimentally observed Pmnb phase is a consequence of the intersection of Imma and P4/mbm space groups, being the result of soft mode condensation at R and M points, respectively. Thus, the Pmnb can be regarded as simultaneous condensations of two soft modes. The phonon dispersion relations of Pmnb suggest that this phase is stable. © 2001 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.1337057
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