Engineering by Mn embedment and adsorption in defective boron nitrogen sheet

• Mn adsorption on B or N vacancy is more stable than Mn embedment.
• The stability is reversed in Mn embedment into B–N vacancy.
• No energy barrier exists between Mn adsorption and embedment.
• h-BN sheet with Mn adsorbed on boron vacancy exhibits half-metallic.

Using first-principles calculations, we performed a comparative study on hexagonal boron nitrogen (BN) sheet with Mn adsorbing on and embedding in three types of vacancies: VB, VN, and VB+N. Our results show that Mn adsorbed VB and VN configurations are more stable than the corresponding embedded configurations. However, Mn embedded VB+N configuration has higher stability than Mn adsorbed VB+N configuration. Nudged elastic band calculations reveal that no energy barrier exists between adsorbed and corresponding embedded configurations. Mn adsorbed VB BN sheet is half-metallic interesting for spin filter applications, while Mn adsorbed VN configuration and Mn embedded VB+N configuration are magnetic semiconductors. The specific distribution of the magnetic moments and the exact charge transfer between Mn atom and defective BN sheets are also found.