Ballistic Сonductivity of Gold Nanotubes

Abstract

The paper presents the results of a theoretical study of the electronic structure and electrical conductivity of single-walled gold nanotubes with chirality indices (4, 0), (5, 0), (6, 0), (7, 0), (4, 4), and (5, 5). The simulations were performed using the density functional theory and the method of nonequilibrium Green’s functions. The Perduew–Burke–Ernzerhof exchange-correlation functional and a two-exponential basis set were used. The importance of using polarized basis sets for the study of electrical properties of gold nanotubes is demonstrated. Analysis of the results showed that the transmission functions of the studied nanotubes depend on their structure in a complex way but, in general, increase with increasing diameter. The dependence of the transmission function on the electron energy does not allow us to speak a priori about the linearity of the current–voltage characteristic of gold nanotubes within a certain finite voltage range. In addition to defect-free single-walled gold nanotubes, gold nanotubes of different diameters with a vacancy-type defect-were also studied. This allowed us to evaluate the effect of such a defect on the atomic structure and electrical conductivity of the single-walled gold nanotubes. It was demonstrated that the conductivity drop can vary within a wide range, correlating with changes in the atomic structure.