Glissile dislocations with transient cores in silicon

Abstract

We report an unexpected characteristic of dislocation cores in silicon. Using first-principles calculations, we show that all the stable core configurations for a non-dissociated 60${}^{\circ }$ dislocation are sessile. The only glissile configuration, previously obtained by nucleation from surfaces, surprinsingly corresponds to an unstable core. As a result, the 60${}^{\circ }$ dislocation motion is solely driven by stress, with no thermal activation. We predict that this original feature could be relevant in situations for which large stresses occur, such as mechanical deformation at room temperature. Our work also suggests that post-mortem observations of stable dislocations could be misleading, and that mobile unstable dislocation cores should be taken into account in theoretical investigations.

References in corpus (4)

• The SIESTA method for ab initio order-N materials simulation
• Efficient index handling of multidimensional periodic boundary conditions
• Theoretical study of dislocation nucleation from simple surface defects in semiconductors
• Dislocation formation from a surface step in semiconductors: an ab initio study

Cited by in corpus (1)

• First-Principles Study of Secondary Slip in Zirconium