Interaction of small gold clusters with carbon nanotube bundles: formation of gold atomic chains.

We use first-principles density functional theory to simulate the interaction of bundles of semiconducting (10, 0) and metallic (6, 6) carbon nanotubes (CNTs) with small gold clusters (Au(n), n = 3, 5) inserted in their interstitial spaces. We find that gold clusters spontaneously evolve to form atomic chains along the axis of nanotubes and induce weak metallicity in the semiconducting nanotubes through charge transfer. We further show that a similar structural evolution of Pt(3) clusters occurs in the interstitial spaces of a (10, 0) CNT bundle. Our calculations show that these structural changes, along with interesting changes in the electronic structure, occur at moderate pressures that are readily achievable in a laboratory, and should be relevant to devices that make use of gold-nanotube contacts.