  We give a detailed discussion of the Quantum Interference Effect Transistor
(QuIET), a proposed device which exploits interference between electron paths
through aromatic molecules to modulate current flow. In the off state, perfect
destructive interference stemming from the molecular symmetry blocks current,
while in the on state, current is allowed to flow by locally introducing either
decoherence or elastic scattering. Details of a model calculation demonstrating
the efficacy of the QuIET are presented, and various fabrication scenarios are
proposed, including the possibility of using conducting polymers to connect the
QuIET with multiple leads.
