First-principles calculations are performed to compute the e<Subscript>33</Subscript> piezoelectric coefficients of GaN, ScN and (Sc<Subscript>x</Subscript>Ga<Subscript>1-x</Subscript>N) alloys exhibiting an alternation of hexagonal GaN, with hexagonal ScN along the c-axis. For Sc compositions larger than 50%, each atom has nearly five nearest neighbors (i.e.,...</subscript></subscript></subscript>

An ideal single vacancy can be formed by removing one carbon atom from a hexagonal network. The vacancy is one of the most important defect structures in carbon nanotubes (CNTs). Vacancies can affect the mechanical, chemical, and electronic properties of CNTs. We have systematically investigated...