Properties of one-dimensional molybdenum nanowires in a confined environment

The atomistic mechanism for the self-assembly of molybdenum into one-dimensional metallic nanowires in a confined environment such as a carbon nanotube is investigated using quantum mechanical calculations. We find that Mo does not organize into linear chains but rather prefers to form four atom per unit cell nanowires that consist of a subunit of a Mo body-centered cubic crystal. Our model explains the 0.3 nm separation between features measured by high-resolution transmission electron microscopy and why the nanotube diameter must be in the 0.70-1.0 nm range to accommodate the smallest stable one-dimensional wire. We also computed the electronic band structure of the Mo wires inside a nanotube and found significant hybridization with the nanotube states, thereby explaining the experimentally observed quenching of fluorescence and the damping of the radial breathing modes as well as an increased resistance to oxidation.