Geometrical and electronic structures of the (5, 3) single-walled gold nanotube from first-principles calculations

The geometrical and electronic structures of the 4 Å-diam perfect and deformed (5, 3) single-walled gold nanotube (SWGT) have been studied based on the density-functional theory in the local-density approximation (LDA). The calculated relaxed geometries show clearly significant deviations from those of the ideally rolled triangular gold sheet. It is found that the different strains have different effects on the electronic structures and density of states of the SWGTs, and the small shear strain can reduce the binding energy per gold atom of the deformed SWGT, which is consistent with the experimentally observed result. Finally, we found the finite SWGT can show the metal-semiconductor transition.

Figure 1

(a) (Color online) The triangular network sheet of gold atoms forming the SWGT. The nearest-neighbor distance between two gold atoms is chosen to be 2.9 Å. A ball-and-stick model of one unit cell for the 4 Å-diam SWGT (5, 3): (b) undeformed structure with its total atom number of 38; (c) torsional strain of $+4.302°$ (23 atoms); (d) torsional strain of $-6.562°$ (five atoms); (e) shear strain of 0.0314 (33 atoms).

Figure 2

Calculated band structures of : (a) perfect SWGT (5, 3); (b), (c), (d), (e) and (f) deformed ones, respectively, under uniaxial stretch strain of 0.05 and 0.1, torsional strain of $+4.302°$ and $-6.562°$, and shear strain of 0.0314. The Fermi level is set at zero.

Figure 3

(Color online) Calculated total DOS (solid line), PDOSs for $d$ electrons (dash line) and $s$ electrons (dot line): (a) perfect SWGT (5, 3); (b), (c), and (d) deformed ones, respectively, under uniaxial strain of 0.1, torsional strain of $+4.302°$, and shear strain of 0.0314. The Fermi level is set at zero.

Figure 4

Calculated band structures of: (a) perfect SWGT (5, 0) (10 atoms); (b) and (c) deformed ones, respectively, under uniaxial stretch strain of 0.1, torsional strain of $+4.715°$ (35 atoms); (d) perfect SWGT (6, 3) SWGT (6 atoms); and (e) and (f) deformed ones, respectively, under uniaxial stretch strain of 0.1, torsional strain of $+6.587°$ (45 atoms). The Fermi level is set at zero.