Chris J Pickard and R J Needs 2009 J. Phys.: Condens. Matter 21 452205 doi:10.1088/0953-8984/21/45/452205
Chris J Pickard1 and R J Needs2
Show affiliationsWe have used density-functional-theory methods to study phases of iron at terapascal (TPa) pressures. Hexagonal-close-packed (hcp) iron is stable from below 0.1 TPa to multi-TPa pressures, where we find a window of 7–21 TPa in which the face-centred-cubic (fcc) phase is slightly more stable. At 34 TPa we find a transition to a body-centred-tetragonal (bct) phase, which is a small distortion of the body-centred-cubic (bcc) structure. The bcc phase also becomes more stable than the hcp above 35 TPa. The bct and bcc phases become considerably more stable than hcp and fcc at even higher pressures, and we expect this result to hold at high temperatures.
71.20.Be Transition metals and alloys
64.70.K- Solid–solid transitions
71.15.Mb Density functional theory, local density approximation, gradient and other corrections
61.50.Ks Crystallographic aspects of phase transformations; pressure effects
Issue 45 (11 November 2009)
Received 6 August 2009, in final form 5 October 2009
Published 21 October 2009
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