文章基本信息

标题：The phase diagram and hardness of carbon nitrides
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作者：Huafeng Dong ; Artem R. Oganov ; Qiang Zhu 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2015
卷号：5
期号：1
DOI：10.1038/srep09870
语种：English
出版社：Springer Nature
摘要：Novel superhard materials, especially those with superior thermal and chemical stability, are needed to replace diamond. Carbon nitrides (C-N), which are likely to possess these characteristics and have even been expected to be harder than diamond, are excellent candidates. Here we report three new superhard and thermodynamically stable carbon nitride phases. Based on a systematic evolutionary structure searches, we report a complete phase diagram of the C-N system at 0–300 GPa and analyze the hardest metastable structures. Surprisingly, we find that at zero pressure, the earlier proposed graphitic-C₃N₄ structure ( ) is dynamically unstable, and we find the lowest-energy structure based on s-triazine unit and s-heptazine unit.