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arXiv 1207.0104cond-mat.mtrl-sci
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两种半导体三维all-sp2碳同素异形体

Two semiconducting three-dimensional all-sp2 carbon allotropes

Chaoyu He, L. Z. Sun, C. X. Zhang, J. X. Zhong

摘要:

利用第一性原理方法研究了两种三维全sp2碳同素异形体sp2-金刚石和sp2-石墨的能量稳定性、动力学稳定性和电子性质。1992年,Michael O 'Keeffe预测了石墨的存在(Phys. Rev. Lett.,68,15,1992.)空间群为Pn-3 m(224),而空间群为Fd-3 m(227)的sp2-金刚石未见报道。结果表明,sp2-金刚石结构比K4-碳和T-碳结构更稳定,sp2-石墨结构比超硬M-碳、W-碳和Z-碳结构更稳定,振动性质计算表明两种结构都是动力学稳定的。有趣的是,sp2-金刚石和石墨都表现为半导体,这与以前提出的全sp2碳同素异形体相反。sp2-金刚石是直接带隙为1.66 eV的半导体,而石墨是间接带隙为2.89 eV的半导体。sp2-金刚石和石墨的低密度和完全的sp2构型在储氢、光催化剂和分子筛等方面具有潜在的应用前景。

英文摘要:

Using first-principles method, we investigate the energetic stability, dynamic stability and electronic properties of two three-dimensional (3D) all-sp2 carbon allotropes, sp2-diamond and cubic-graphite. The cubic-graphite was predicted by Michael O'Keeffe in 1992 (Phys. Rev. Lett., 68, 15, 1992.) possessing space group of Pn-3m (224), whereas the sp2-diamond with the space group Fd-3m (227) same as that of diamond has not been reported before. Our results indicate that sp2-diamond is more stable than previously proposed K4-carbon and T-carbon, and cubic-graphite is even more stable than superhard M-carbon, W-carbon and Z-carbon.The calculations on vibrational properties show that both structures are dynamically stable. Interestingly, both sp2-diamond and cubic-graphite behave as semiconductors which are contrary to previously proposed all-sp2 carbon allotropes. The sp2-diamond is a semiconductor with a direct band gap of 1.66 eV, and cubic-graphite is an indirect semiconductor with band gap of 2.89 eV. The very lower densities and entirely sp2 configures of sp2-diamond and cubic-graphite can be potentially applied in hydrogen-storage, photocatalysts and molecular sieves.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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