Quantum Interference Hybrid Single-Electron Transistor

Emanuele Enrico, Elia Strambini, Francesco Giazotto

Published Sep 27, 2016• 0 citations

Abstract

The manipulation of single charge quanta in solid state systems has been a field of active interest for several decades. At the basis of such structures lays the Coulombic repulsion between electrons in a small metallic island yielding the so-called Coulomb-blockade regime. Many quantum phenomena, such as the tunnelling effect or the Josephson coupling in superconducting junctions, have been exploited so far to control the charging state of a conducting island, and enable a number of applications ranging from on-chip cooling and current generation to single-photon detection. Yet, in all Coulombic systems the external control parameters play a crucial role, reaching sometimes a rather complex experimental configuration. Here we show that quantum interference established in a superconducting nanowire can provide a phase-tunable energy barrier which allows charge manipulation with enhanced functionalities. This additional degree of freedom for single electronics stems from the coupling between magnetic flux-dependent proximity effect and charging levels discretization present in a Coulomb-blockaded island. Our quantum interference nanostructure represents the first realization of a superconducting hybrid single-electron transistor called SQUISET in which the charging landscape is phase-coherently manipulated by an external magnetic flux. The interferometric nature of the transistor adds new perspectives to single electronics making it a promising alternative building block in quantum metrology, coherent caloritronics, and quantum information technology.

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