skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Mobility of tungsten clusters on tungsten surfaces

Abstract

It is reported on an accelerated molecular dynamics investigation of surface transport mechanisms on W surfaces. These mechanisms likely influence the formation of nano-fuzz in fusion plasma-facing conditions. The simulations use an embedded-atom potential to investigate the diffusion mechanisms of W clusters (W n, n = 2–9) on W(1 1 0) and W(1 0 0) surfaces at 1000 K, reaching timescales beyond 10 microseconds. A number of fast moving adatom species, W n (n = 2–6), were observed. In contrast, slightly larger clusters W n (n = 7–9), especially W 8, exhibit significantly lower diffusivities. The diffusion mechanisms of W n clusters on the W(1 1 0) surface are complex, with the most common elementary steps involving hops of monomers and dimers. Moreover, we observe tetramer hopping in the diffusion processes of W n (n = 4–7), trimer hopping in W n (n = 5, 6, 8), and pentamer hopping in W 5 on the W(1 1 0) surface. W n (n ≤ 3) and metastable W n (n > 3) clusters on the W(1 0 0) surface diffuse predominantly through monomer exchange with surface atoms. However, W clusters containing square tetramers are essentially immobile on the W(1 0 0)more » surface at 1000 K.« less

Authors:
 [1];  [2];  [3];  [3]
  1. Univ. of Tennessee, Knoxville, TN (United States). Dept. of Nuclear Engineering
  2. Univ. of Tennessee, Knoxville, TN (United States). Dept. of Nuclear Engineering; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Fusion and Materials for Nuclear Systems Div.
  3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Div.
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF); UT-Battelle LLC/ORNL, Oak Ridge, TN (Unted States)
Sponsoring Org.:
USDOE Office of Science (SC); USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1565734
DOE Contract Number:  
AC05-00OR22725
Resource Type:
Journal Article
Journal Name:
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms
Additional Journal Information:
Journal Volume: 453; Journal Issue: C; Journal ID: ISSN 0168-583X
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
Instruments & Instrumentation; Nuclear Science & Technology; Physics

Citation Formats

Yang, L., Wirth, B. D., Perez, Danny, and Voter, Arthur F. Mobility of tungsten clusters on tungsten surfaces. United States: N. p., 2019. Web. doi:10.1016/j.nimb.2019.05.078.
Yang, L., Wirth, B. D., Perez, Danny, & Voter, Arthur F. Mobility of tungsten clusters on tungsten surfaces. United States. doi:10.1016/j.nimb.2019.05.078.
Yang, L., Wirth, B. D., Perez, Danny, and Voter, Arthur F. Thu . "Mobility of tungsten clusters on tungsten surfaces". United States. doi:10.1016/j.nimb.2019.05.078.
@article{osti_1565734,
title = {Mobility of tungsten clusters on tungsten surfaces},
author = {Yang, L. and Wirth, B. D. and Perez, Danny and Voter, Arthur F.},
abstractNote = {It is reported on an accelerated molecular dynamics investigation of surface transport mechanisms on W surfaces. These mechanisms likely influence the formation of nano-fuzz in fusion plasma-facing conditions. The simulations use an embedded-atom potential to investigate the diffusion mechanisms of W clusters (Wn, n = 2–9) on W(1 1 0) and W(1 0 0) surfaces at 1000 K, reaching timescales beyond 10 microseconds. A number of fast moving adatom species, Wn (n = 2–6), were observed. In contrast, slightly larger clusters Wn (n = 7–9), especially W8, exhibit significantly lower diffusivities. The diffusion mechanisms of Wn clusters on the W(1 1 0) surface are complex, with the most common elementary steps involving hops of monomers and dimers. Moreover, we observe tetramer hopping in the diffusion processes of Wn (n = 4–7), trimer hopping in Wn (n = 5, 6, 8), and pentamer hopping in W5 on the W(1 1 0) surface. Wn (n ≤ 3) and metastable Wn (n > 3) clusters on the W(1 0 0) surface diffuse predominantly through monomer exchange with surface atoms. However, W clusters containing square tetramers are essentially immobile on the W(1 0 0) surface at 1000 K.},
doi = {10.1016/j.nimb.2019.05.078},
journal = {Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms},
issn = {0168-583X},
number = C,
volume = 453,
place = {United States},
year = {2019},
month = {8}
}