In this proposal the principal investigator will study the feasibility of a Quantum Field-Effect Directional Coupler (QFED). The QFED is a proposed device that intends to exploit the wave nature of electrons confined to a very small semiconductor structures. The QFED consists basically of two parallel electron waveguides sufficiently closely spaced over a certain length (the interaction length) so that electrons can be transferred from one waveguide to the other by quantum mechanical tunneling. In a QFED, electrons transfer alternatively between the two waveguides as the electron wave packet travels down the coupler. For a coupler to transfer any given fraction of the electrons from one waveguide to the other, coupling between the waveguides can be controlled without changing their interaction length. This is achieved by the field-effect action of a metal gate running through the middle of the coupler. The QFED behaves as a current switch, much like an entire Emitter-Coupler Logic gate.
