Calculations of crystal-structure stabilities of Ce under pressure

Journal Article · Sun Nov 15 04:00:00 EST 1992 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.46.12981· OSTI ID:7039784

Eriksson, O; Wills, J M; Boring, A M ^[1]

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1. Center for Materials Science, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States) Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

The total energies of the observed crystal structures of Ce (face-centered cubic (fcc), orthorhombic, and body-centered tetragonal (bct)) under pressure have been calculated, using the local-density approximation. The linear-muffin-tin-orbital calculations were full potential, all electron, and fully relativistic. The experimental data for the different crystallographic transitions are well reproduced by the calculations and we have extracted two terms that are mainly responsible for the {alpha}{r arrow}{alpha}{prime} transition: a one-electron term and a Madelung term. The {alpha}{r arrow}{alpha}{prime} transition is driven by the increasing importance of the 4{ital f} contribution with decreasing volume. This finding is also supported by a calculation without the 4{ital f} contribution to the cohesion which yields the {alpha}{prime} phase unstable. The {alpha}{prime}{r arrow}bct transition is found to be somewhat more complex in nature since it is quite heavily influenced also by the 5{ital d} electrons. The calculated ground state is (correctly) found to be fcc and the equilibrium volume as well as the bulk modulus are in good agreement with experiment. The present {ital ab} {ital initio} calculation of a crystallographic phase diagram of an {ital f} electron system suggests delocalized 4{ital f} electrons exist in the high-pressure phases, including the {alpha} phase, of Ce.

• OSTI ID: 7039784
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 46:20; ISSN PRBMD; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
CERIUM
CRYSTAL STRUCTURE
DIAGRAMS
ELECTRONIC STRUCTURE
ELEMENTS
METALS
MUFFIN-TIN POTENTIAL
PHASE DIAGRAMS
POTENTIALS
PRESSURE EFFECTS
RARE EARTHS
STABILITY