  Dislocations are a central concept in materials science, which dictate the
plastic deformation and damage evolution in materials. Layered materials such
as graphite admit two general types of interlayer dislocations: basal and
prismatic dislocations, of which prismatic dislocations have been relatively
less studied. Using density functional theory (DFT) calculations, we have
examined different prismatic core structures in graphite and evaluated their
structure, energetics and mobility. We find close energetic interplay between
bonded and "free-standing" core structures in both zigzag and armchair
directions, with a reconstructed stable zigzag core identified. We explore
grain boundaries and prismatic dislocation pile-up, identifying metastable
structures which may be important in energy storage. The role of interlayer
stacking in core structure, dislocation glide and climb is also considered
in-depth. Our calculations suggest that the prismatic dislocation core is
stable up to high temperatures of approximately 1500K in bulk graphite. Above
this temperature, the breaking of bonds in the dislocation core can facilitate
climb, grain-boundary motion, and the annealing of damage through prismatic
dislocation glide.
