Interference Effects in a Tunable Quantum Point Contact Integrated with an Electronic Cavity

Abstract

We show experimentally how quantum interference can be produced using an integrated quantum system comprising an arch-shaped short quantum wire (or quantum point contact, QPC) of 1D electrons and a reflector forming an electronic cavity. On tuning the coupling between the QPC and the electronic cavity, fine oscillations are observed when the arch QPC is operated in the quasi-1D regime. These oscillations correspond to interference between the 1D states and a state which is similar to the Fabry-Perot state and suppressed by a small transverse magnetic field of 60mT. Tuning the reflector, we find a peak in resistance which follows the behavior expected for a Fano resonance. We suggest that this is an interesting example of a Fano resonance in an open system which corresponds to interference at or near the Ohmic contacts due to a directly propagating, reflected discrete path and the continuum states of the cavity corresponding to multiple scattering. Remarkably, the Fano factor shows an oscillatory behavior taking peaks for each fine oscillation, thus, confirming coupling between the discrete and continuum states. The results indicate that such a simple quantum device can be used as building blocks to create more complex integrated quantum circuits for possible applications ranging from quantum-information processing to realizing the fundamentals of complex quantum systems.

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Cited by in corpus (6)

• Cavity-mediated coherent coupling between distant quantum dots
• Temperature Dependence of Spin-Split Peaks in Transverse Electron Focusing
• Magnetoresistance in an electronic cavity coupled to one-dimensional systems
• Incipient singlet-triplet states in a hybrid mesoscopic system
• Local signatures of electron-electron scattering in an electronic cavity
• Imaging signatures of the local density of states in an electronic cavity