Defect states of complexes involving a vacancy on the boron site in boronitrene

Abstract

First principles calculations have been performed to investigate the ground state properties of freestanding monolayer hexagonal boronitrene (h-BN). We have considered monolayers that contain native point defects and their complexes, which form when the point defects bind with the boron vacancy on the nearest neighbour position. The changes in the electronic structure are analysed to show the extent of localization of the defect-induced mid-gap states. The variations in formation energies suggest that defective h-BN monolayers that contain carbon substitutional impurities are the most stable structures irrespective of the changes in growth conditions. The high energies of formation of the boron vacancy complexes suggest that they are less stable, and their creation by ion bombardment would require high energy ions compared to point defects. Using the relative positions of the derived mid-gap levels for the double vacancy complex, it is shown that the quasi donor-acceptor pair interpretation of optical transitions is consistent with stimulated transitions between electron-hole states in boronitrene.

First principles molecular dynamics study of nitrogen vacancy complexes in boronitrene

“…It is therefore plausible that, at sufficiently high temperatures, the kinetic energy of the migrating nitrogen can cause it to trap into the local minimum (point F) to give a metastable V B configuration with frozen-in disorder in B-N bond. The above situation contrasts with the spontaneous transformation of the V B +B N complex to V N observed in our previous study [19]. Because the formation energies are lowest when V N forms in Brich condition and highest when V N +V B complex forms in the same condition, the V N +N B complex is unable to trap into metastable configurations beyond a critical point on the energy landscape.…”

Half-metallic ferromagnetism in substitutionally doped boronitrene

“…Large quasiparticle corrections apply to the band gap of boronitrene. 52,55 Hence, the range in which the electron chemical potential varies during charge injection is influenced by such corrections. Nevertheless, the electronic structure of boronitrene is known 55 to give an improved band gap and a better description of exchange coupling, when the hybrid functional of Heyd, Scuseria, and Ernzerhof (HSE06) is used.…”

“…The single-atom carbon substitutions (i.e. C B an d C N ) have the lowest formation energy, 52 and can also induce half-metallicity in h-BN nanostructures. 33 We therefore consider h-BN monolayers that are doped with type B complexes.…”

“…Nevertheless, further electron (or hole) doping beyond -3 (or +3) charge states results in zero magnetic moments. Taking into consideration the known deficiencies of the PBE functional approximation in predicting the electronic structure of boronitrene, 52,55 we also investigate the charge-tunability of the defect-induced magnetism in the prototypical C 1B +C 3N complex, under the effect of quasiparticle-corrections using the HSE functional, and compare the results with similar PBE…”

“…C N ) sublattices. 52 Recently, Berseneva et al 37 showed that the stability of carbon substitutional defects in the hybrid BCN layer is sensitive to the number (N C ) of C atoms. The spontaneous formation of B or N clusters in monolayer h-BN is energetically not favourable because of the high energy penalties required [see The formation energies of type B complexes are sensitive to the type of atoms that terminated the edges of the complexes, and the number N C of substituted atoms.…”