Eur. Phys. J. B (2017) 90: 101
https://doi.org/10.1140/epjb/e2017-80056-1

Regular Article

Trapping of helium atom by vacancy in tungsten: a density functional theory study

¹ Institute of Nuclear Materials, School of Materials Science and Engineering, University of Science and Technology Beijing (USTB), Beijing 100083, P.R. China
² LCP, Institute of Applied Physics and Computational Mathematics, P.O. Box 8009, Beijing 100088, P.R. China
³ Beijing Computational Science Research Center, Beijing 100193, P.R. China

^a e-mail: zhangyujuan@ustb.edu.cn

Received: 24 January 2017
Received in final form: 14 April 2017
Published online: 24 May 2017

Abstract

The interaction between helium (He) atom and vacancy defect in tungsten (W) has been investigated by using first-principles simulations. We have obtained that the most stable site for He in tungsten is the substitutional position because He can keep its own electronic structure at this position. In the studied tungsten system, vacancy can act as a trapping center for surrounding He atom with negative trapping energy. The migration behaviors of He atom at tetrahedral interstitial site in W, which can be trapped by vacancy but the final position is almost unchanged comparing with its initial position through structural relaxation, have been predicted and discussed. It is also found that single He atom prefers to go through an octahedral site rather than through a direct path to the vacancy, and the stronger the interaction between He atom and vacancy is, the lower the migration barrier will be.