Stability and mobility of vacancy-H complexes in Al
Journal article, 2013

The effect of hydrogen loading on the stability and mobility of vacancy-H complexes in aluminum is determined by applying DFT and the minimum-mode-following method. The binding energy per H-atom within a complex is found to range from -0.36 eV/atom to -0.34 eV/atom for an occupancy of, respectively, a single and eight H-atoms. When eight H-atoms are neighboring the vacancy the total binding energy becomes -2.72 eV. However, already at a load level of two H-atoms the total binding energy reaches -0.70 eV, which fully compensates the vacancy creation energy. It is observed that for complexes with four or more H-atoms the vacancy gets pinned, as the diffusion barrier increases by a factor of two, reaching a value of 1.03 eV or more. The explanation for the increased energy barrier is that at the higher hydrogen load levels the system must traverse an energetically unfavorable configuration where two or more H-atoms are separated from the vacancy. As a possible consequence of the decreased mobility and increased stability, highly loaded vacancy-H complexes are likely to act as nucleation sites for extended defects.


Magnús Benediktsson

Chalmers, Applied Physics, Materials and Surface Theory

Kjartan K. G. Myrdal

Lund University

University of Iceland

Pramod Maurya

University of Iceland

Indian Institute of Technology, Guwahati

Andreas Pedersen

University of Iceland

Journal of Physics Condensed Matter

0953-8984 (ISSN)

Vol. 25 37 375401- 375401

Areas of Advance

Materials Science

Subject Categories

Condensed Matter Physics



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