Vacancy behavior in a compressed fcc Lennard-Jones crystal

Technical Report · Tue Dec 01 00:00:00 EST 1981

DOI:https://doi.org/10.2172/5669586· OSTI ID:5669586

Beeler, Jr, J R

This computer experiment study concerns the determination of the stable vacancy configuration in a compressed fcc Lennard-Jones crystal and the migration of this defect in a compressed crystal. Isotropic and uniaxial compression stress conditions were studied. The isotropic and uniaxial compression magnitudes employed were 0.94 less than or equal to eta less than or equal to 1.5, and 1.0 less than or equal to eta less than or equal to 1.5, respectively. The site-centered vacancy (SCV) was the stable vacancy configuration whenever cubic symmetry was present. This includes all of the isotropic compression cases and the particular uniaxial compression case (eta = ..sqrt..2) that give a bcc structure. In addition, the SCV was the stable configuration for uniaxial compression eta < 1.29. The out-of-plane split vacancy (SV-OP) was the stable vacancy configuration for uniaxial compression 1.29 < eta less than or equal to 1.5 and was the saddle-point configuration for SCV migration when the SCV was the stable form. For eta > 1.20, the SV-OP is an extended defect and, therefore, a saddle point for SV-OP migration could not be determined. The mechanism for the transformation from the SCV to the SV-OP as the stable form at eta = 1.29 appears to be an alternating sign (101) and/or (011) shear process.

• Research Organization: Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 5669586
• Report Number(s): LA-9121-MS; ON: DE82007054; TRN: 82-008435
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
FCC LATTICES
LATTICE PARAMETERS
COMPRESSION
COMPUTERIZED SIMULATION
INTERATOMIC FORCES
LENNARD-JONES POTENTIAL
THEORETICAL DATA
VACANCIES
CRYSTAL DEFECTS
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CUBIC LATTICES
DATA
INFORMATION
NUMERICAL DATA
POINT DEFECTS
POTENTIALS
SIMULATION
656000* - Condensed Matter Physics