Gw. Watson et al., ATOMISTIC SIMULATION OF DISLOCATIONS, SURFACES AND INTERFACES IN MGO, Journal of the Chemical Society. Faraday transactions, 92(3), 1996, pp. 433-438
Citations number
45
Categorie Soggetti
Chemistry Physical","Physics, Atomic, Molecular & Chemical
A new simulation code for modelling extended defects e.g. linear (disl
ocations) and planar (surfaces and grain boundaries) at the atomistic
level is introduced. One of the key components is the ability to calcu
late the Coulombic potential of a solid with one-dimensional periodici
ty. This approach has been applied to screw dislocations in MgO and we
have evaluated the structure (including core size) and stability of t
he [100] and 1/2[110] screw dislocations. The 1/2[110] dislocation, wh
ich has the shortest Burgers vector, was found to be more stable, as p
redicted by elasticity theory, although the simulations show that elas
ticity theory underestimates the energy difference. In addition, it ha
s been shown that by using this new computer simulation code METADISE,
following the approach of Tasker, the structure and energetics of sur
faces and interfaces can be calculated. This method has been applied t
o modelling micro-faceting and it was found that micro-facetted {110}
and {111} surfaces of MgO are the most stable forms of these surfaces.
The formation energy of tilt grain boundaries in MgO ({h10} and {h20}
) as a function of misorientation angle was also investigated and it w
as found that for the {h10} series the formation energy is proportiona
l to the interfacial bond density while no such pattern can be found f
or the {h20} series.