Open AccessStructure and formation of misfit dislocations in an epitaxial fcc film
Author(s) -
Zhou Nai-Gen,
Lang Zhou,
Du Dan-Xu
Publication year - 2006
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.55.372
Subject(s) - partial dislocations , materials science , nucleation , dislocation , stacking fault , condensed matter physics , epitaxy , atomic units , crystallography , atom (system on chip) , aluminium , tetrahedron , stacking , embedded atom model , molecular dynamics , chemical physics , nanotechnology , thermodynamics , physics , composite material , chemistry , computational chemistry , layer (electronics) , quantum mechanics , nuclear magnetic resonance , computer science , embedded system
Three-dimensional molecular dynamics simulation of epitaxial growth of fcc aluminum film with a negative misfit of 0.05, under atomic deposition, has been carried out. An embedded atom method (EAM) potential is employed for computing atomic interaction in aluminum. Formation of misfit dislocation appears in the simulated growth process. Atomistic analysis of the film shows that, in the beginning the misfit dislocation consists of two Shockley partial dislocations with a stacking fault zone between them. The Burgers vectors of the two partial dislocations are of 〈211〉/6 type, and the width of the stacking fault is 1.8 nm, which agrees well with theoretical calculation. During further deposition growth, the dislocation pair can slide, but their distance remains stable. Further analysis shows that the dislocation pair forms in a local surface disordering-ordering process, like the local melting-crystallization. Atomic scale squeezed-out tetrahedrons are found to form near the surface and soon slide back in the anor of statistical fluctuation. Under some circumstances, however, a squeezed-out tetrahedron causes disorder of its neighboring atoms, and developes into the observed local disorder zone, which later becomes the nucleation site for the formation of the Shockley dislocation pair.