Carbon nanotubes and related fullerene structures are investigated for their usefulness as memory and logic elements, as well as manipulation tools, in molecular electronics.
Multi-wall carbon nano-capsules containing charged fullerene ions, such as K@C60+, behave as tunable two-level systems. Transitions between the two states can be induced by applying an electric field between the end caps of the outer capsule. Since the position of the encapsulated fullerene can be associated with a bit value, these systems can be used as nonvolatile memory elements.
Due to their small size and absence of incoherent scattering, nanotubes themselves behave as quantum conductors. Whereas the conductance of ballistic conductors is an integer multiple of the conductance quantum in most systems, the weak inter-wall interactions in multi-wall nanotubes may block some of the quantum conductance channels and redistribute the current nonuniformly over the individual tubes. These results provide a natural explanation for the unexpected non-integer conductance values observed for multi-wall nanotubes.
Nanotubes may also be used for a precise, semi-continuous deposition of atoms on nanostructures. Such atoms, when intercalated in nanotubes, are dragged by an electric current, which may be induced and controlled by the relative phase shift between two laser beams irradiating the tubes at frequencies \omega and 2\omega.
ANL Physics Division Colloquium Schedule