First-principles study of Au-decorated carbon nanotubes

Highlights: • The adsorption of Au atoms on the carbon nanotube is studied by using density functional theory. • The adsorption of Au atoms can introduce impurity states in the band gap. • Considerable SO splitting (∼130 meV) can be obtained in the impurity states. • The SO splitting decreases with the increase of the concentration of Au atoms. The electronic structures and spin-orbit (SO) coupling of carbon nanotubes with adsorbed Au atoms are investigated based on density functional theory. Three kinds of zigzag single-walled CNT (8,0), (10,0) and (12,0) are selected. The Au atoms prefer to adsorb on the top of C atoms. The adsorption of Au atoms can introduce impurity states in the band gap, modifying the electronic properties of systems. Furthermore, the influence of SO coupling on these impurity states is also explored. Considerable SO splitting (∼130 meV) can be obtained. We find that the SO splitting decreases with the increase of the concentration of Au atoms, which can be ascribed to the interaction between Au atoms, suppressing the SO splitting. Our work provides imperative understanding on the electronic properties and SO coupling effect in Au-decorated CNTs.