Tight-binding study of tilt grain boundaries in diamond
- Ames Laboratory, US Department of Energy, Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States)
- 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 Lab. (ORNL), Oak Ridge, TN (United States)
- DOE Contract Number:
- AC05-96OR22464; W-7405-ENG-82
- OSTI ID:
- 285614
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 54, Issue 1; Other Information: PBD: Jul 1996
- Country of Publication:
- United States
- Language:
- English
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