ELECTROCONDUCTANCE OSCILLATIONS AND QUANTUM INTERFERENCE IN BALLISTICNANOSTRUCTURES

We report theoretical studies of a quantum-interference phenomenon in ballistic nanometer-size constrictions analogous to the electrostatic Aharonov-Bohm effect. Modulating an applied-potential step V(T) in one of the branches of a multiply connected system allows the observation of conductance oscillations, even in the absence of magnetic fields, as they are produced by quantum-interference between voltage-shifted s tates in the different branches. Electric depopulation of subbands can also be seen at larger V(T). We show that these aperiodic oscillation s are strong for realistic structural parameters, robust against incre asing temperature, and compare well with the expected phase changes in a simple single-channel model.