Interference-modulated conductance in a three-terminal nanotube system

We study ballistic conductance in a three-terminal carbon nanotube system a nd show that conductance between two of the terminals can be controlled via the third terminal. The conductance is modulated by tuning the energy spec trum of the third terminal. Such a system may provide the core of a nanotra nsistor. We show more generally that the quasi one-dimensional nature of na notubes can persist in branched topologies and that insights gained in anal yzing one-dimensional systems can therefore be applied in analyzing network s of nanotubes.