Atomic Core Structures Associated to the Threading Dislocation with \langle 1\bar{1}00\rangle Burgers Vector and [0001] Line Direction in GaN

概要

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The \langle 1\bar{1}00 \rangle edge dislocation in GaN has been investigated by means of atomistic computer simulation. It's core structure exhibits three configurations that are related to the location of the origin of displacements imposed to the atoms when generating the dislocation in the initial configuration. They are described by: (a) 8- and 4-coordinated channels (8/4 core); (b) 8-, 5-, and 5-coordinated channels (8/5/5 core); and (c) 9- and 5-coordinated channels (9/5 core). An additional configuration where the \langle 1\bar{1}00 \rangle dislocation decomposes in two 8-coordinated channels \mathbf{a}= 1/3\langle 1\bar{2}10 \rangle dislocations is also generated and it exhibits the lowest energy. This is in agreement with high resolution transmission electron microscopy observations and image simulations carried out on an asymmetric \Sigma 7 [0001] tilt grain boundary in which only cores of elemental \mathbf{a} type dislocations have been determined.
2013-11-25