Atomic and electronic structure of high-energy grain boundaries in silicon and carbon

We have studied the structure and electronic properties of a few high-energy twist grain boundaries, the (0 0 1) φ=53.1°, or Σ5, and the (0 0 1) φ=43.6°, or Σ29, in the covalently bonded systems Si and C by means of tight-binding molecular dynamics. We describe the parallelization of the code and the main results obtained for the structural and electronic properties of the grain boundaries. The role of structural disorder in silicon is compared to the chemical (bonding) disorder in carbon.