中国物理B ›› 2009, Vol. 18 ›› Issue (12): 5468-5473.doi: 10.1088/1674-1056/18/12/056

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Energetics and electronic structure of a single copper atomic chain wrapped in a carbon nanotube: a first-principles study

张建民1, 杜秀娟1, 王素芳1, 徐可为2   

  1. (1)College of Physics and Information Technology, Shaanxi Normal University, Xi'an 710062, China; (2)State Key Laboratory for Mechanical Behaviour of Materials, Xi'an Jiaotong University, Xi'an 710049, China
  • 收稿日期:2009-03-21 修回日期:2009-05-16 出版日期:2009-12-20 发布日期:2009-12-20
  • 基金资助:
    Project supported by the State Key Development Program for Basic Research of China (Grant No 2004CB619302).

Energetics and electronic structure of a single copper atomic chain wrapped in a carbon nanotube: a first-principles study

Zhang Jian-Min(张建民)a)†, Du Xiu-Juan(杜秀娟)a), Wang Su-Fang(王素芳)a), and Xu Ke-Wei(徐可为) b)   

  1. a College of Physics and Information Technology, Shaanxi Normal University, Xi'an 710062, China; b State Key Laboratory for Mechanical Behaviour of Materials, Xi'an Jiaotong University, Xi'an 710049, China
  • Received:2009-03-21 Revised:2009-05-16 Online:2009-12-20 Published:2009-12-20
  • Supported by:
    Project supported by the State Key Development Program for Basic Research of China (Grant No 2004CB619302).

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摘要： In the generalized gradient approximation, the energy and electronic structure are investigated for a single copper atomic chain wrapped in (4, 4), (5, 5) and (6, 6) armchair carbon nanotubes by using the first-principles projector-augmented wave potential within the framework of density functional theory. The results show that the (4, 4) and (5, 5) tubes are too narrow to wrap a Cu chain, but the (6, 6) tube is nearly ideal to wrap a Cu chain on its centre axis. Wider tubes are anticipated to wrap more than one Cu chain spontaneously with forces amounting to a fraction of a nanonewton. Although the tube--chain interaction decreases with the increase of the tube diameter of (4, 4), (5, 5) and (6, 6) successively, the charge density of the Cu@(6, 6) combined system still does not show complete superposition of that of the pristine (6, 6) tube and Cu chain. Successively reducing the restrictions of (4, 4), (5, 5) and (6, 6) tubes on the Cu chain leads to a reduction in shift of the highest peak of the Cu chain towards lower energies, that is from -0.5177~eV of the isolated Cu chain to -1.36785~eV, -0.668~eV and -0.588~eV for the Cu@(4, 4), Cu@(5, 5) and Cu@(6, 6) systems, respectively. In reverse, the strong metallic character of the Cu chain also enhances the metallic character of the combined systems so that the broader pseudogaps of the pristine carbon nanotubes around the Fermi level change into the narrow pseudogaps of the combined systems.

Abstract: In the generalized gradient approximation, the energy and electronic structure are investigated for a single copper atomic chain wrapped in (4, 4), (5, 5) and (6, 6) armchair carbon nanotubes by using the first-principles projector-augmented wave potential within the framework of density functional theory. The results show that the (4, 4) and (5, 5) tubes are too narrow to wrap a Cu chain, but the (6, 6) tube is nearly ideal to wrap a Cu chain on its centre axis. Wider tubes are anticipated to wrap more than one Cu chain spontaneously with forces amounting to a fraction of a nanonewton. Although the tube--chain interaction decreases with the increase of the tube diameter of (4, 4), (5, 5) and (6, 6) successively, the charge density of the Cu@(6, 6) combined system still does not show complete superposition of that of the pristine (6, 6) tube and Cu chain. Successively reducing the restrictions of (4, 4), (5, 5) and (6, 6) tubes on the Cu chain leads to a reduction in shift of the highest peak of the Cu chain towards lower energies, that is from -0.5177~eV of the isolated Cu chain to -1.36785~eV, -0.668~eV and -0.588~eV for the Cu@(4, 4), Cu@(5, 5) and Cu@(6, 6) systems, respectively. In reverse, the strong metallic character of the Cu chain also enhances the metallic character of the combined systems so that the broader pseudogaps of the pristine carbon nanotubes around the Fermi level change into the narrow pseudogaps of the combined systems.

Key words: copper atomic chain, carbon nanotube, electronic structures, first-principle

中图分类号:  (Density functional theory, local density approximation, gradient and other corrections)

  • 71.15.Mb
71.15.Ap (Basis sets (LCAO, plane-wave, APW, etc.) and related methodology (scattering methods, ASA, linearized methods, etc.)) 73.22.-f (Electronic structure of nanoscale materials and related systems)