Four superhard sp3 hybrid cubic boron nitride polymorphs: A first principles calculations

In this study, four sp(3) hybrid boron nitride polymorphs were proposed based on first principles calculations. The calculation results indicated that, at ambient conditions, four polymorphs are stable based on the criteria of dynamic and mechanical stability. At ambient conditions, they are thermodynamically metastable than h-BN, but more stable under high pressure conditions. In these four boron nitride phases, atoms are assembled in cubic symmetry, which are all sp(3) hybrid cubic diamond-like structures, and the results showed that the Vickers hardness of them are as hard as c-BN, indicating they are potential superhard materials. Meanwhile, these four structures are considered as wide band gap semiconductor structures with direct band gap. Therefore, these four boron nitride structures have great potential as photovoltaic electronic devices and cutting tools. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The study proposed four sp(3) hybrid boron nitride polymorphs that are stable at ambient conditions, more stable under high pressure conditions, and have the potential of being superhard materials with wide band gap semiconductor structures with direct band gap.