  The paper presents a study of two full-core, edge dislocations of opposite
Burgers vectors in 4H-SiC, conducted using the first-principles density
functional theory methods. We have determined the creation energy of the
dislocations as a function of distance between their cores. The radial
distribution function has been applied to examine strong impact of the
dislocations on the local crystal structure. The analysis of the electronic
structure reveals mid-gap levels induced by broken atomic bonds in the
dislocation core. The maps of charge distribution and electrostatic potential
have been calculated and the significant decrease of the electrostatic barriers
in the vicinity of the dislocation cores has been quantified. The obtained
results have been discussed in the light of available experimental data.
