J. Phys. III France
Volume 7, Numéro 12, December 1997
Page(s) 2281 - 2292
DOI: 10.1051/jp3:1997259
J. Phys. III France 7 (1997) 2281-2292

Dislocation and Grain Boundary Energies in Si and Ge from an Anharmonic Bond Charge Model

H. Teichler and J. Wilder

Institut f$\ddot{\rm u}$r Metallphysik, Universit$\ddot{\rm a}$t G$\ddot{\rm o}$ttingen, 37073 G$\ddot{\rm o}$ttingen, Germany

(Received 3 October 1996, revised 16 September 1997, accepted 16 Septembre 1997)

The paper presents calculated line energy values for the reconstructed 60 $^{\circ}$ and 90 $^{\circ}$ glide-set partial dislocations in Si and Ge, formation and migration energy for the reconstructed kink on the reconstructed 90 $^{\circ}$ partials, and energy data for the symmetric $\Sigma = 9 < 011 >$ and for two variants of the symmetric $\Sigma = 11 < 011 >$ tilt grain boundaries. Criteria are formulated to identify interatomic force field models which are able to provide reliable energy estimates. The anharmonic bond charge (a.bc) model is introduced as an example that approximately fulfills the basic criteria, i.e., describes well the second and third order elastic constants and the phonon dispersion curves. Deviations between energy estimates from the a.bc model and less reliable approaches are discussed. It is shown that in case of the $\Sigma = 11 < 011 >$ tilt grain boundary the a.bc model gives different energetical ranking for the so-called $\Sigma = 11$A and the $\Sigma = 11$B variants in Si and Ge, in agreement with the experimental observations.

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