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Energy landscape of silicon tetra‐interstitials using an optimized classical potential
Author(s) -
Du Yaojun A.,
Lenosky Thomas J.,
Hennig Richard G.,
Goedecker Stefan,
Wilkins John W.
Publication year - 2011
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201147137
Subject(s) - nucleation , silicon , chemical physics , tetra , materials science , dimer , molecular physics , ground state , maxima and minima , crystallography , atomic physics , chemistry , physics , optoelectronics , mathematical analysis , mathematics , medicinal chemistry , organic chemistry
Mobile single interstitials can grow into extended interstitial defect structures during thermal anneals following ion implantation. The silicon tetra‐interstitials present an important intermediate structure that can either provide a chain‐like nucleation site for extended structures or form a highly stable compact interstitial cluster preventing further growth. In this paper, dimer searches using the tight‐binding (TB) model by Lenosky et al. and density functional calculations show that the compact ground‐state $I_{4}^{a} $ and the I 4 ‐chain are surrounded by high‐lying neighboring local minima. To furthermore explore the phase space of tetra‐interstitial structures an empirical potential is optimized to a database of silicon defect structures. The minima hopping method combined with this potential extensively searches the energy landscape of tetra‐interstitials and discovers several new low‐energy I 4 structures. The second lowest‐energy I 4 structure turns out to be a distorted ground‐state tri‐interstitial bound with a single interstitial, which confirms that the ground‐state tri‐interstitial may serve as a nucleation center for the extended defects in silicon.