Electroconductance oscillations and quantum interference in ballistic nanostructures

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 ${\mathit{V}}_{\mathit{T}}$ 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 states in the different branches. Electric depopulation of subbands can also be seen at larger ${\mathit{V}}_{\mathit{T}}$. We show that these aperiodic oscillations are strong for realistic structural parameters, robust against increasing temperature, and compare well with the expected phase changes in a simple single-channel model.