Abstract Two novel superhard boron-carbon-nitride allotropes of P 3 ¯ m1-BCN and I41md-BCN are proposed through structure searching within density functional theory (DFT) calculations. Obtained results reveal that P 3 ¯ m1-BCN and I41md-BCN are both mechanically stable and dynamically stable at ambient condition. The minimum peak stresses for the P 3 ¯ m1-BCN and I41md-BCN are 41.4 GPa in [0 0 1] direction and 48.6 GPa in (1 0 0)[0 0 1] direction, respectively. The calculated theoretical hardness of P 3 ¯ m1-BCN is 68.5 GPa, evidently greater than that of other BCN allotropes and c-BN, while I41md-BCN shows a weaker theoretical hardness of 61.8 GPa. The results imply that P 3 ¯ m1-BCN and I41md-BCN are potentially superhard materials.

中文翻译：

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两个超硬 BCN 同素异形体的第一性原理计算：P3¯m1-BCN 和 I41md-BCN

摘要 通过密度泛函理论(DFT) 计算中的结构搜索，提出了P 3 ¯ m1-BCN 和I41md-BCN 的两种新型超硬硼-碳-氮化物同素异形体。获得的结果表明，P 3 ¯ m1-BCN 和 I41md-BCN 在环境条件下均具有机械稳定性和动态稳定性。P 3 ¯ m1-BCN 和 I41md-BCN 的最小峰值应力在 [0 0 1] 方向分别为 41.4 GPa 和 (1 0 0)[0 0 1] 方向为 48.6 GPa。P 3 ¯ m1-BCN 的计算理论硬度为 68.5 GPa，明显高于其他 BCN 同素异形体和 c-BN，而 I41md-BCN 的理论硬度较弱，为 61.8 GPa。结果表明 P 3 ¯ m1-BCN 和 I41md-BCN 是潜在的超硬材料。