Elastic properties of edges in BN and SiC nanoribbons and of boundaries in C-BN superlattices: A density functional theory study

Using density functional theory calculations, we compute the edge energies and stresses for edges of SiC and BN nanoribbons, and the boundary energies and stresses for domain boundaries of graphene-BN superlattices. SiC and BN armchair nanoribbons show pronounced edge relaxations, which obliterate the threefold oscillatory behavior of the edge stress reported for graphene. Our calculations show small boundary stresses in graphene-BN superlattices, suggesting that such domain boundaries will not experience severe deformation. We have also found that the C-terminated and Si-terminated zigzag edges in SiC nanoribbons have different compressive stresses which results in different rippling behavior of these edges.