Theoretical study of kinks on screw dislocation in silicon

Laurent Pizzagalli (1) , Andreas Pedersen (2) , Andri Arnaldsson (2) , Hannes Jónsson (2) , Pierre Beauchamp (1)

1 LMP - Laboratoire de métallurgie physique
2 Science Institute

Theoretical calculations of the structure, formation and migration of kinks on a non-dissociated screw dislocation in silicon have been carried out using density functional theory calculations as well as calculations based on interatomic potential functions. The results show that the structure of a single kink is characterized by a narrow core and highly stretched bonds between some of the atoms. The formation energy of a single kink ranges from 0.9 to 1.36 eV, and is of the same order as that for kinks on partial dislocations. However, the kinks migrate almost freely along the line of an undissociated dislocation unlike what is found for partial dislocations. The effect of stress has also been investigated in order to compare with previous silicon deformation experiments which have been carried out at low temperature and high stress. The energy barrier associated with the formation of a stable kink pair becomes as low as 0.65 eV for an applied stress on the order of 1 GPa, indicating that displacements of screw dislocations likely occur via thermally activated formation of kink pairs at room temperature.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Laurent Pizzagalli, Andreas Pedersen, Andri Arnaldsson, Hannes Jónsson, Pierre Beauchamp. Theoretical study of kinks on screw dislocation in silicon. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2008, 77, pp.064106. ⟨10.1103/PhysRevB.77.064106⟩. ⟨hal-00274424⟩