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arXiv 1912.03260cond-mat.mes-hall
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碳纳米管内铌纳米线的催化形成

Catalytic Formation of Narrow Nb Nanowires inside Carbon Nanotubes

Dan Liu, David Tomanek

摘要:

我们提出了一种以前未探索的方法来形成Nb纳米线从NbCl $_3$分子内的碳纳米管(CNT)。我们已经研究了这个反应的从头算密度泛函计算,发现它是催化促进石墨碳的存在下。我们的研究结果表明,NbCl $_3$在CNT上的化学吸附伴随着~0.5个电子的电荷转移到纳米管壁,这显著地削弱了Nb-Cl键。我们发现Nb的bcc结构不受CNT内纳米线的小直径的影响。我们还确定了纳米线和周围纳米管之间的强共价键,其伴随着从表面Nb原子到纳米管的<0.5e的类似电荷转移。在受限的几何结构中,体Nb在E $_F$处的大电子态密度没有太大变化,这表明Nb的超窄纳米线可以保持其超导行为,并在准一维几何结构中形成约瑟夫森结,同时被包围的CNT结构保护免受环境影响。

英文摘要:

We propose a previously unexplored way to form Nb nanowires from NbCl$_3$ molecules inside carbon nanotubes (CNTs). We have studied this reaction by ab initio density functional calculations and found it to be catalytically promoted in presence of graphitic carbon. Our results suggest that chemisorption of NbCl$_3$ on the CNT is accompanied by a charge transfer of ~0.5 electrons to the nanotube wall, which significantly weakens the Nb-Cl bond. We found that the bcc structure of Nb is not affected by the small diameter of the nanowire inside a CNT. We have also identified strong covalent bonds between the nanowires and the surrounding nanotube that are accompanied by a similar charge transfer of <0.5 e from surface Nb atoms to the nanotube. The large electronic density of states of bulk Nb at E$_F$ is not changed much in the confined geometry, suggesting that ultra-narrow nanowires of Nb may keep their superconducting behavior and form Josephson junctions in the quasi-1D geometry while being protected from the ambient by the enclosing CNT structure.

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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