Nevidomskyy Andriy H, Csányi Gábor, Payne Michael C
Theory of Condensed Matter Group, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom.
Phys Rev Lett. 2003 Sep 5;91(10):105502. doi: 10.1103/PhysRevLett.91.105502.
We investigate the nitrogen substitutional impurity in semiconducting zigzag and metallic armchair single-wall carbon nanotubes using ab initio density functional theory. At low concentrations (less than 1 at. %), the defect state in a semiconducting tube becomes spatially localized and develops a flat energy level in the band gap. Such a localized state makes the impurity site chemically and electronically active. We find that if two neighboring tubes have their impurities facing one another, an intertube covalent bond forms. This finding opens an intriguing possibility for tunnel junctions, as well as the functionalization of suitably doped carbon nanotubes by selectively forming chemical bonds with ligands at the impurity site. If the intertube bond density is high enough, a highly packed bundle of interlinked single-wall nanotubes can form.
我们使用从头算密度泛函理论研究了半导体锯齿形和金属扶手椅形单壁碳纳米管中的氮替代杂质。在低浓度（小于1原子%）下，半导体管中的缺陷态在空间上局域化，并在带隙中形成一个平坦的能级。这种局域态使杂质位点在化学和电子方面具有活性。我们发现，如果两个相邻的管子其杂质相互面对，就会形成管间共价键。这一发现为隧道结以及通过在杂质位点与配体选择性地形成化学键来对适当掺杂的碳纳米管进行功能化开辟了一个有趣的可能性。如果管间键密度足够高，就可以形成一个高度密集的相互连接的单壁纳米管束。
