Introducing the Triangular Defect to Effectively Engineer the Wide Band Gap of Boron Nitride Nanoribbons with Zigzag and Even Armchair Edges

By means of the first-principles computations, we investigated the electronic and magnetic properties of zigzag and armchair boron nitride nanoribbons (BNNRs) with triangular vacancy defects, where two series of triangular defects with different sizes are considered by sampling the N-vacancies V N, V 3N+B, and V 6N+3B and B-vacancies V B, V 3B+N, and V 6B+3N, respectively. It is revealed that introducing the triangular defect can effectively conquer the bottleneck of the wide band gap for the zigzag and even armchair BNNRs, which severely hinders the application of BN-based nanomaterials in the nanodevices. Particularly, independent of the edge chirality, the triangular defects (e.g., V B, V 6B+3N and V N, V 6N+3B ) with the dangling bonds on N/B atoms in two series can convert the originally nonmagnetic to magnetic behaviors and more effectively engineer the wide band gap of BNNRs, even achieving the intriguing spin-gapless semiconducting and half-metallic behaviors. Additionally, the type and size of the triangular defect can also play a crucial role in affecting the electronic and magnetic properties of BNNRs. Obviously, beyond most of the approaches reported, introducing the triangular defect can be an effective strategy to engineer the rather robust wide band gap of BNNRs with the armchair edge, besides the zigzag-edged ones. These fascinating findings can promote the practical applications of the BN-based nanomaterials in multifunctional and spintronic nanodevices.