A new reconstruction core of the 30° partial dislocation in silicon

ABSTRACT

The ${30}^{\circ }$ partial dislocation in silicon is investigated theoretically in the framework of the fully discrete Peierls–Nabarro model and first-principles calculations. A new reconstructed core composed of a periodic arrangement of one tetragon and two heptagons (477-core) is proposed. Similar to the ${90}^{\circ }$ partial dislocation, we find that there are actually two types of reconstructed cores for the ${30}^{\circ }$ partial dislocation, namely, a well-known 558-core and a new 477-core. The energy of the 477-core is 0.137 eV/Å higher than that of the 558-core. However, from the $abinitio$ molecular dynamics simulation, we found that the 477-core may have a macroscopic lifetime for temperature below 30 K. The full kinks and the partial kinks due to the appearance of the 477-core are also studied. Remarkably, it is found that formation and migration of the global kinks deeply involve with the partial kinks, and the creation and motion of partial kinks can be attributed to the rotation of a single bond. Our results are helpful in understanding the mechanism of kink nucleation and the plasticity of silicon.

KEYWORDS:

• Dislocation in silicon
• lattice theory of dislocations
• core reconstruction
• partial kinks

Disclosure statement

No potential conflict of interest was reported by the authors.