Tight-binding study of tilt grain boundaries in diamond

Journal Article · Mon Jul 01 04:00:00 EDT 1996 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.54.132· OSTI ID:285614

Morris, J R ^[1]; Fu, C L ^[2]; Ho, K M ^[1]

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1. Ames Laboratory, US Department of Energy, Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States)
2. Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

We have examined a number of symmetric tilt grain boundary structures in diamond, using a transferable tight-binding (TB) carbon potential. Utilizing {ital O}({ital N}) tight-binding molecular dynamics, we are able to simulate several thousands of atoms, allowing us to examine low-angle boundaries with large periodicities. The lowest energy structure is the {l_brace}111{r_brace} twin boundary, corresponding to the {Sigma}=3 70.53{degree} grain boundary. For angles less than 70.53{degree}, the boundaries are composed of a series of {ital b}={l_angle}01{bar 1}{r_angle} edge dislocations. The core structures of these dislocations are composed of five- and seven-atom rings. For these low-angle structures, the tight-binding energies have trends similar to those found using a Tersoff potential; both models give results that are consistent with linear elasticity theory. For the high-angle {l_brace}211{r_brace} and {l_brace}311{r_brace} boundaries, the tight-binding model predicts a reconstruction along the {l_angle}011{r_angle} direction, in order to eliminate dangling bonds. {copyright} {ital 1996 The American Physical Society.}

• Research Organization: Oak Ridge National Laboratory
• DOE Contract Number: AC05-96OR22464; W-7405-ENG-82
• OSTI ID: 285614
• Journal Information: Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 1 Vol. 54; ISSN 0163-1829; ISSN PRBMDO
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COMPUTERIZED SIMULATION
DIAMONDS
DISLOCATIONS
GRAIN BOUNDARIES
MATHEMATICAL MODELS
ORIENTATION
TIGHT BINDING APPROXIMATION
TWINNING