Glide dislocations in diamond: first-principles calculations of similarities with and differences from silicon and the effects of hydrogen

Abstract

We review first-principles calculations of dislocation core structure in diamond, and draw out similarities with and differences from silicon. Primary differences are in hybridization changes in carbon and in the different behaviour of H interacting with dislocations. In both materials, condensation of a homogeneous distribution of H atoms should result, first, in formation of small H aggregates with the appearance of a glide dislocation dipole and, second, in formation of larger platelets based on the half-stacking-fault model.

First-principles calculations on the structure of hydrogen aggregates in silicon and diamond

“…The choice of structures was influenced by our earlier result for diamond [27], where a hydrogenated faulted 90…”

Computational Study of Interstitial Hydrogen Atoms in Nano-Diamond Grains Embedded in an Amorphous Carbon Shell

“…8. Larger aggregates, which superficially resemble parts of the structures in this figure were previously examined in [41].…”

Atomic-scale models of dislocation cores in minerals: progress and prospects

“…Using the dipole approach, the dislocation structure and formation energy can be calculated given a sufficiently large simulation cell and the core energy can be found from the variation in the total energy of the simulation cell with cell size. Examples of the sort of calculation that can be undertaken using this approach include studies of molybdenum and tantalum (Ismail-Beigi and Arias, 2000), of semiconductors (Bigger et al, 1992;Liu et al, 1995;Heggie et al, 2000;Kaplan et al, 2000;Cai et al, 2001) and of diamond and graphite (Heggie et al, 2000;Ewels et al, 2001;Heggie et al, 2002;Martsinovich et al, 2003;Suarez-Martinez et al, 2007). To our knowledge, the series of studies of dislocations in diamond and graphite represent the only examples of super-cells being used for the study of dislocations in minerals.…”

“…Heggie et al, 2000) and 1D periodic cluster-based models (Blumenau et al, 2002) to investigate a wide range of dislocation properties using DFT and tight-binding methods. Key results include the identification of the mechanisms of graphitization (Ewels et al, 2001) and hydrogen-facilitated kink mobility (Heggie et al, 2002) in diamond. An interesting effect of imposing periodic boundary conditions has been described recently in a study of dislocations in iron.…”