Calculation of the atomic structure of the ∑ = 13 (θ = 22.6°) [001] twist boundary in gold

Abstract

The structure of the ∑ = 13 (θ = 22.6°) [001] twist boundary in gold is computed using the Embedded Atom Method (EAM). The atomic positions near the boundary are computed and found to be in good agreement with the recent X-ray diffraction results of Fitzsimmons and Sass. The amplitude of the thermal displacements is also computed from the EAM using Monte Carlo simulations and compared with the results for the average Debye-Waller factor of the boundary obtained by Fitzsimmons. Burkel and Sass. The vibrational amplitudes of the atoms adjacent to the boundary are found to be larger than in the bulk and the enhancement is greater for vibrations in the plane of the boundary than for vibrations normal to the boundary. These results obtained using the EAM are also compared to results obtained using two different pair interactions. The main difference between the results using the many-body EAM interactions and the pair interactions is that the overall expansion of the boundary is found to be smaller using the EAM.