Demonstration of device conductance modulation by electrostatic control of the electron phase

Abstract

In this paper we describe a novel effect observed in a quantum wire containing two parallel "artificial" (i.e., electrostatically defined antidots) impurities. At low magnetic fields we observe a series of resistance peaks. These occur at magnetic fields for which classical electron trajectories are commensurate with the device geometry. The resistance peaks are modulated by periodic oscillations that can be observed both as a function of the applied magnetic field or the gate voltage, which controls the size of the impurities. These oscillations are analyzed in terms of the classical action of ballistic electrons on closed trajectories, the related phase gained along these trajectories, and the resulting quantum interference effect. We show that these oscillations when observed as a function of gate voltage are consistent with changes of the electron wavelength along part of the electron trajectory. The device conductance is thus being modulated by the electrostatic control of the electron phase.