文章基本信息

标题：Dynamical stability of body center cubic iron at the Earth’s core conditions
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作者：Wei Luo ; Börje Johansson ; Olle Eriksson 等
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2010
卷号：107
期号：22
页码：9962-9964
DOI：10.1073/pnas.1004076107
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Here, using self-consistent ab initio lattice dynamical calculations that go beyond the quasiharmonic approximation, we show that the high-pressure high-temperature bcc-Fe phase is dynamically stable. In this treatment the temperature-dependent phonon spectra are derived by exciting all the lattice vibrations, in which the phonon-phonon interactions are considered. The high-pressure and high-temperature bcc-Fe phase shows standard bcc-type phonon dispersion curves except for the transverse branch, which is overdamped along the high symmetry direction {Gamma}-N, at temperatures below 4,500 K. When lowering the temperature down to a critical value TC, the lattice instability of the bcc structure is reached. The pressure dependence of this critical temperature is studied at conditions relevant for the Earth's core.
关键词：ab initio ; anharmonic lattice dynamics ; high pressure and high temperature ; inner core