Carbyne from First Principles: Chain of C Atoms, a Nanorod or a Nanorope
Carbyne from First Principles: Chain of C Atoms, a Nanorod or a Nanorope
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DOI：
10.1021/nn404177r
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发表时间：
2013-11-01
期刊：
影响因子：
17.1
通讯作者：
Yakobson, Boris I.
中科院分区：
文献类型：
--
作者：
Liu, Mingjie;Artyukhov, Vasilii I.;Yakobson, Boris I.
我们报告了使用第一性原理计算对卡炔特性的广泛研究。我们研究了卡宾对拉伸、弯曲和扭转变形的机械响应。在张力下，卡宾的硬度大约是已知最硬材料的两倍，并且具有高达 7.5 x 10(7) N 的无与伦比的比强度。 m/kg，需要大约 10 nN 的力才能破坏单个原子链。 Carbyne 具有相当大的室温余辉长度，约为 14 nm。令人惊讶的是，卡炔的扭转刚度可以为零，但可以通过末端适当的官能团“打开”。此外，在适当的终止下，碳炔可以通过机械扭转转变为磁性半导体状态。我们重建了等效连续弹性表示，提供了卡宾的全套弹性模量，显示了其极端的机械性能（例如，标称杨氏模量为 32.7 TPa，有效机械厚度为 0.772 埃）。我们还发现卡宾的应变和带隙之间存在有趣的耦合，在张力下，带隙急剧增加，在 10% 应变下从 2.6 eV 增加到 4.7 eV。最后，我们研究了卡炔作为纳米级电缆的性能，并评估了其针对自聚集的化学稳定性，发现卡炔-卡炔交联反应的激活势垒为 0.6 eV，以及每 17 个碳原子 (2.2 nm) 1 个交联的两条平行卡炔链的平衡交联密度。
We report an extensive study of the properties of carbyne using first-principles calculations. We investigate carbyne's mechanical response to tension, bending, and torsion deformations. Under tension, carbyne is about twice as stiff as the stiffest known materials and has an unrivaled specific strength of up to 7.5 x 10(7) N . m/kg, requiring a force of similar to 10 nN to break a single atomic chain. Carbyne has a fairly large room-temperature persistence length of about 14 nm. Surprisingly, the torsional stiffness of carbyne can be zero but can be "switched on" by appropriate functional groups at the ends. Further, under appropriate termination, carbyne can be switched into a magnetic semiconductor state by mechanical twisting. We reconstruct the equivalent continuum elasticity representation, providing the full set of elastic moduli for carbyne, showing its extreme mechanical performance (e.g., a nominal Young's modulus of 32.7 TPa with an effective mechanical thickness of 0.772 angstrom). We also find an interesting coupling between strain and band gap of carbyne, which is strongly increased under tension, from 2.6 to 4.7 eV under a 10% strain. Finally, we study the performance of carbyne as a nanoscale electrical cable and estimate its chemical stability against self-aggregation, finding an activation barrier of 0.6 eV for the carbyne-carbyne cross-linking reaction and an equilibrium cross-link density for two parallel carbyne chains of 1 cross-link per 17 C atoms (2.2 nm).