Authors: A.J.R. da Silva, F.D. Novaes, E.Z. da Silva and A. Fazzio
Affilation: Universidade de Sao Paulo, Brazil
Pages: 181 - 182
Keywords: gold nanowires, large Au-Au distances, atomistic simulations
Surprisingly large interatomic distances, in the range of 3.6-4.0 Å, have been reported for one atom thick gold nanowires by various experimental groups. From a theoretical viewpoint, no one has been able to reproduce the above mentioned large distances for clean nanowires, the maximum obtained values being of the order of 3.0-3.1 Å. In an attempt to explain these results we have decided, therefore, to systematically study, based on ab initio total energy Density Functional Theory calculations, the effect of impurities in gold nanowires under stress. We conclude that the presence of C impurities in Au nanowires would result in distances significantly larger than 3.6 Å (approximately 3.9 Å). After ruling out C as a possible explanation, the obtained Au-Au distances for the H case are in excellent agreement with the experimental results, suggesting that H impurities are most likely the source of the yet unexplained large Au-Au distances in the range of 3.6 ± 0.2 Å. Finally, an extremely large Au-Au distance (4.8 Å) has also been observed experimentally, and it has been previously suggested that this distance could be caused by two C atoms inserted into the Au nanowires. However, we also obtain that these C-C impurities under stress would result in excessively large distances (of the order of 5.3 Å), and we propose that S atoms could be the explanation for this experimental observation.