Dynamical stability of body center cubic iron at the Earth's core conditions
2010 (English)In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 107, no 22, 9962-9964 p.Article in journal (Refereed) Published
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 T-C, 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.
Place, publisher, year, edition, pages
2010. Vol. 107, no 22, 9962-9964 p.
ab initio, anharmonic lattice dynamics, high pressure and high temperature, inner core
IdentifiersURN: urn:nbn:se:uu:diva-136067DOI: 10.1073/pnas.1004076107ISI: 000278246000012OAI: oai:DiVA.org:uu-136067DiVA: diva2:376137