About cookies on this site Our websites require some cookies to function properly (required). In addition, other cookies may be used with your consent to analyze site usage, improve the user experience and for advertising. For more information, please review your options. By visiting our website, you agree to our processing of information as described in IBM’sprivacy statement. To provide a smooth navigation, your cookie preferences will be shared across the IBM web domains listed here.
Publication
Journal of Physics Condensed Matter
Paper
Bravais phases of Fe under pressure from first principles
Abstract
The structure and stability of four Bravais phases of Fe under pressure are determined by a procedure which first looks for minima of the internal energy E at constant volume V and then tests the states at the minima for stability (or instability) by showing that the Gibbs free energy G at constant pressure p is a minimum (or not a minimum) with respect to all possible strains. The phases considered here are either body-centered tetragonal (bct), which includes body-centered cubic (bcc) and face-centered cubic (fcc), or rhombohedral (rh). The results include showing that bcc Fe becomes unstable at 1500 kbar, that fcc Fe is stable at p = 0, that a phase transition from bcc to fcc is thermodynamically favored at 290 kbar, that a bct phase at c/a = 0.89 is unstable up to 2700 kbar and that a rh phase with angle α = 60.5° is stable at p = 0 with E slightly higher than that for fcc Fe. © 2008 IOP Publishing Ltd.