Ab initio study of phonons and structural stabilities of the perovskite-type MgSiO3

K. Parlinski, Y. Kawazoe

研究成果: Article査読

37 被引用数 (Scopus)

抄録

Using the local-density approximation, calculating the Hellmann-Feynman forces, applying the direct method and deriving the phonon dispersion relations, the stability of the perovskite-like structures of MgSiO3 at T = 0 have been studied. The cubic Pm3̄m phase shows a dispersion-less soft phonon branch spreading from the R to M points of the cubic Brillouin zone. This soft branch persists up to high pressures of 150 GPa. The low-symmetry phases I4/mcm and Imma, P4/mbm can be considered as a result of the soft mode condensation at the M and R points, respectively. These phases prove to be unstable at T = 0. The experimentally observed Pmnb phase is a consequence of the intersection of Imma and P4/mbm space groups. Thus, it can be regarded as a simultaneous condensation of two soft modes: one at the M and a second at the R high-symmetry points of the cubic Brillouin zone. The phonon dispersion relations of Pmnb show that this phase is stable and its optical phonons appear above 4.0 THz only.

本文言語English
ページ(範囲)49-58
ページ数10
ジャーナルEuropean Physical Journal B
16
1
DOI
出版ステータスPublished - 2000 7 1

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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