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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, 杜秀娟, 王素芳, 徐可为
2009 (12):
5468-5473.
doi: 10.1088/1674-1056/18/12/056
摘要
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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.
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