  Due to the wide range of possible applications, atomically thin
two-dimensional heterostructures have attracted much attention. In this work,
using first-principles calculations, we investigated the structural and
electronic properties of planar AlN/GaN hybrid heterojunctions with the
presence of vacancies at their interfaces. Our results reveal that a single
vacant site, produced by the removal of Aluminum or Gallium atom, produces
similar electronic band structures with localized states within the bandgap. We
have also observed a robust magnetic behavior. A nitrogen-vacancy, on the other
hand, induces the formation of midgap states with reduced overall
magnetization. We have also investigated nanotubes formed by rolling up these
heterojunctions. We observed that tube curvature does not substantially affect
the electronic and magnetic properties of their parent AlN/GaN heterojunctions.
For armchair-like tubes, a transition from direct to indirect bandgap was
observed as a consequence of changing the system geometry from 2D towards a
quasi-one-dimensional one. The magnetic features presented by the AlN/GaN
defective lattices make them good candidates for developing new spintronic
technologies.
