Abstract Superhard materials have always attracted people's interesting due to their extensive industrial applications. In this work, two reasonable superhard monoclinic allotropes of boron nitrides with space group of Cm have been designed based on previously proposed M-carbon structure using first-principles calculations. Our results show that Cm-BN-1 and Cm-BN-2 are dynamically stable, and they are direct semiconductors with bandgap of 2.69 and 3.90 eV, respectively. Moreover, they could be potential superhard materials with Vickers hardness of 58.0 and 60.4 GPa, respectively. This work provides insights for exploring new superhard boron nitrides materials.

中文翻译：

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M-碳结构中的超硬单斜BN同素异形体

摘要 超硬材料因其广泛的工业应用而一直引起人们的兴趣。在这项工作中，基于先前提出的 M-碳结构，使用第一性原理计算设计了两种合理的空间群为 Cm 的氮化硼超硬单斜同素异形体。我们的结果表明，Cm-BN-1 和 Cm-BN-2 是动态稳定的，它们是带隙分别为 2.69 和 3.90 eV 的直接半导体。此外，它们可能是潜在的超硬材料，维氏硬度分别为 58.0 和 60.4 GPa。这项工作为探索新的超硬氮化硼材料提供了见解。