Stacking faults in group-IV crystals: Anab initiostudy

Intrinsic and extrinsic stacking faults along the $\left[111\right]$ direction in cubic SiC, Si, and C are studied within a first-principles scheme based on density-functional theory and the local-density approximation. In contrast to stacking fault energies for Si and C, we find them to be negative for SiC, possibly one part of the explanation for the large variety of hexagonal and rhombohedral polytypes. The formation energies are compared with experimental and theoretical data available and the chemical trends are derived for the geometrical changes. The electronic structure is calculated for the energetically favorable stacking faults in SiC.