Resistance of copper nanowires and comparison with carbon nanotube bundles for interconnect applications using first principles calculations

TLDR

Recent experiments motivate the investigation of copper nanowire and carbon nanotube bundle resistances. Using first‑principles DFT and Landauer formalism, the authors calculated electronic band structures and fundamental resistances of copper nanowires of various diameters and compared them with empirical predictions, and similarly evaluated resistances of single‑walled carbon nanotube bundles. The study finds that copper nanowires smaller than ~60 nm exhibit resistances exceeding Ohm’s law predictions, while single‑walled carbon nanotube bundles of comparable size have lower resistances than copper wires.

Abstract

We have studied the electronic properties and the band structure of copper nanowires for various diameters using first principles density functional methods and a supercell approach. The resistances of copper nanowires were computed on the basis of the Landauer formalism and compared with those obtained from an empirical approach. The fundamental resistances of small copper nanowires (∼60 nm diameter) are found to be larger than those predicted by Ohm's law. In parallel, we have computed the fundamental resistances for bundles of single walled carbon nanotubes and compared them with that of a single copper wire of similar dimensions. We find that the resistance of carbon nanotube bundles is smaller than that of the copper wires for dimensions below 60 nm. Our results are discussed in light of recent experiments.