Session Y22: Ferroelectric and Structural Phase Transitions
8:00 AM–11:00 AM, Friday, March 25, 2011
Room: D163
Sponsoring Unit:
DCMP
Chair: Jason Lashley, Los Alamos National Laboratory
Abstract ID: BAPS.2011.MAR.Y22.8
Abstract: Y22.00008 : Calculated temperature dependence of elastic constants and phonon dispersion of hcp and bcc beryllium
9:24 AM–9:36 AM
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Abstract 
Authors:
Steven Hahn
(Ames Laboratory and Iowa State University)
Sergiu Arapan
(Uppsala University)
Bruce Harmon
(Ames Laboratory and Iowa State University)
Olle Eriksson
(Uppsala University)
Conventional first principle methods for calculating lattice dynamics are unable to calculate high temperature thermophysical properties of materials containing modes that are entropically stabilized. In this presentation we use a relatively new approach called self-consistent \textit{ab initio} lattice dynamics (SCAILD) to study the hcp to bcc transition (1530 K) in beryllium. The SCAILD method goes beyond the harmonic approximation to include phonon-phonon interactions and produces a temperature-dependent phonon dispersion. In the high temperature bcc structure, phonon-phonon interactions dynamically stabilize the N-point phonon. Fits to the calculated phonon dispersion were used to determine the temperature dependence of the elastic constants in the hcp and bcc phases.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2011.MAR.Y22.8