Can we achieve ultra-low resistivity in carbon nanotube-based metal composites?

A concept for creating a future ultra-low-resistivity material based on a carbon nanotube-metal composite is presented. Using a simple effective-medium model it is shown that a room-temperature resistivity 50% lower than Cu is achievable. This article sets a goal for future R&D activities, although a number of technical as well as scientific problems are to be solved before realising the suggested concept. The ultra-low resistivity is possible because the ballistic conducting carbon nanotubes have an electron mean free path several orders of magnitude longer than metals like Cu and Ag. This implies that a system with parallel-connected tubes can indeed have a room-temperature resistivity far below the resistivity of conventional metal conductors like Al, Cu and Ag.