Phys. Rev. Lett. 78, 4063–4066 (1997)First-Principles Determination of the Soft Mode in Cubic ZrO2Received 30 January 1997; published in the issue dated 26 May 1997 A direct approach to calculate the phonon dispersion using an ab initio force constant method is introduced. The phonon dispersion and structural instability of cubic ZrO2 are found using a supercell method in the local-density approximation. The force constants are determined from the Hellmann-Feynman forces induced by the displacement of an atom in the 2×2×2 fcc supercell. This size of the supercell gives “exact” phonon frequencies at γ,X,L,W Brillouin zone points. The phonon dispersion curves show a pronounced soft mode at the X point, in agreement with the experimentally observed cubic to tetragonal phase transition. © 1997 The American Physical Society URL:
http://link.aps.org/doi/10.1103/PhysRevLett.78.4063
DOI:
10.1103/PhysRevLett.78.4063
PACS:
63.20.-e, 61.50.Ks, 63.70.+h
See AlsoComment: F. Detraux, Ph. Ghosez, and X. Gonze, Long-Range Coulomb Interaction in ZrO2, Phys. Rev. Lett. 81, 3297 (1998). Reply: K. Parlinski, Z. Q. Li, and Y. Kawazoe, Parlinski, Li, and Kawazoe Reply:, Phys. Rev. Lett. 81, 3298 (1998). |
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