skip to main content

Title: Waltzing of a helium pair in tungsten: Migration barrier and trajectory revealed from first-principles

Despite well documented first-principles theoretical determination of the low migration energy (0.06 eV) of a single He in tungsten, fully quantum mechanical calculations on the migration of a He pair still present a challenge due to the complexity of its trajectory. By identifying the six most stable configurations of the He pair in W and decomposing its motion into rotational, translational, and rotational-translational routines, we are able to determine its migration barrier and trajectory. Our density functional theory calculations demonstrate a He pair has three modes of motion: a close or open circular two-dimensional motion in (100) plane with an energy barrier of 0.30 eV, a snaking motion along [001] direction with a barrier of 0.30 eV, and a twisted-ladder motion along [010] direction with the two He swinging in the plane (100) and a barrier of 0.31 eV. The graceful associative movements of a He pair are related to the chemical-bonding-like He-He interaction being much stronger than its migration barrier in W. The excellent agreement with available experimental measurements (0.24–0.32 eV) on He migration makes our first-principles result a solid input to obtain accurate He-W interatomic potentials in molecular dynamics simulations.
Authors:
 [1] ;  [2] ;  [1] ;  [1] ;  [2]
  1. School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China)
  2. (China)
Publication Date:
OSTI Identifier:
22299860
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 4; Journal Issue: 6; Other Information: (c) 2014 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CHEMICAL BONDS; DENSITY FUNCTIONAL METHOD; EV RANGE; HELIUM; INTERACTIONS; MIGRATION; MOLECULAR DYNAMICS METHOD; QUANTUM MECHANICS; SIMULATION; SOLIDS; TUNGSTEN