Sc-B₂₄N₂₄: A New Low-Density Allotrope of BN

Like atoms, nanoclusters can also serve as building blocks for new materials. Here, based on the synthesized cagelike B24N24 clusters, we establish a new sp3-hybridized BN allotrope, termed as sc-B24N24. The geometry, stability, equation of state, mechanical properties, and electronic and optical properties of this superatomic structure are systematically investigated using first-principles calculations. The results reveal that sc-B24N24 is energetically, dynamically, and mechanically stable. The analysis of Young’s modulus and ideal strength shows that sc-B24N24 is mechanically anisotropic due to the cubic symmetry. In particular, the analysis of electronic and optical properties shows that it is a semiconductor with a wide direct band gap. Remarkably, the endohedrally doped V@sc-B24N24 exhibits a ferromagnetic (FM) half-metallicity ground state with 100% spin polarization. Moreover, the encapsulated V atom preserved its highly atom-like magnetic moment (5.0 μB). The findings obtained in this work highlight a low-density BN allotrope with basic building blocks of a hollow cage, which is favorable for doping or trapping foreign impurity atoms to obtain the desired magnetic properties, being anticipated to have important applications in the field of spintronics.