A first-principles investigation on the effect of the divacancy defect on the band structures of boron nitride (BN) nanoribbons

• All the BNNR systems with the 5–8–5 defect are the nonmagnetic semiconductors.
• 5–8–5 defect more effectively narrows the wide band gap than the reported SW defect.
• The defect orientation and position play a crucial role in decreasing the band gap.
• The reduced band gap is mainly attributed to the new states from the 5–8–5 defect.

On the basis of the comprehensive first-principles computations, we investigated the geometries, electronic and magnetic properties of zigzag and armchair boron nitride nanoribbons (BNNRs) with the divacancy defect of 5–8–5 ring fusions formed by removing B–N pair, where the defect orientation and position are considered. Our computed results reveal that all of the defective BNNRs systems can uniformly exhibit nonmagnetic semiconducting behavior, and the formation of the divacancy 5–8–5 defect can significantly impact the band structures of BNNRs with not only the zigzag but also armchair edges, where their wide band gaps are reduced and the defect orientation and position play an important role. Clearly, introducing divacancy defect can be a promising and effective approach to engineer the band structures of BNNRs, and the present computed results can provide some valuable insights for promoting the practical applications of excellent BN-based nanomaterials in the nanodevices.

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