Abstract Submitted to the    NANOTUBE'04 Conference:

We have developed a first-principles pseudopotential method to calculate the quantum conductance of nanostructures under finite bias. The present method allows us to calculate the self-consistent potential nad wavefunctions across a nano-sized junction for a given chemical potential difference. To test the present algorithm, the conductance of a few nanostructures with various contact geometries has been calculated. We have also performed first-principles pseudopotential calculations for the field emission from carbon nanotubes by solving the time-dependent Schroedinger equations under high applied voltage. Both capped and open-ended geometries are considered. Carbon atoms bridging two walls are assumed to exist in the open-ended double-wall tubes. The outer wall screens the external field very effectively in general. Double-wall nanotubes with at least one metallic wall are shown to produce more stable emission current than single-wall nanotubes. Implications to the performa nce of the actual field emission display developed in the industry are discussed.