Quantized current in a quantum-dot turnstile using oscillating tunnel barriers

Kouwenhoven, Leo P.; Johnson, A. T. Charlie; Vaart, N.C. van der; Harmans, C.J.P.M.; Foxon, C.T.

doi:10.1103/physrevlett.67.1626

Cited by 488 publications

(414 citation statements)

References 10 publications

Supporting

Mentioning

406

Contrasting

Order By: Relevance

“…This device ideally generates a quantized output current, I P = nef , where n is an integer and f is the frequency of an external periodic drive. Several enabling technologies have already been developed including metal/oxide tunnel barrier devices 6,7 , normal-metal/superconductor turnstiles 8,9 , graphene double quantum dots 10 , donor-based pumps [11][12][13] , silicon-based quantum dot pumps [14][15][16][17][18] and GaAs-based quantum dot pumps [19][20][21][22][23][24][25][26][27] . To date, the latter scheme provides the lowest uncertainty of 1.2 parts per million (ppm) yielding current in excess of 150 pA 27 .…”

mentioning

confidence: 99%

An Accurate Single-Electron Pump Based on a Highly Tunable Silicon Quantum Dot

et al. 2014

View full text Add to dashboard Cite

Nanoscale single-electron pumps can be used to generate accurate currents, and can potentially serve to realize a new standard of electrical current based on elementary charge. Here, we use a silicon-based quantum dot with tunable tunnel barriers as an accurate source of quantized current. The charge transfer accuracy of our pump can be dramatically enhanced by controlling the electrostatic confinement of the dot using purposely engineered gate electrodes. Improvements in the operational robustness, as well as suppression of non-adiabatic transitions that reduce pumping accuracy, are achieved via small adjustments of the gate voltages. We can produce an output current in excess of 80 pA with experimentally determined relative uncertainty below 50 parts per million.As early as one and a half centuries ago, J. C. Maxwell envisaged the need for a system of standards based on phenomena at the atomic scale and directly related to invariant constants of nature. 1 However, Maxwell could not anticipate that, in order to harness the behaviour of the world at the nanometer scale, a completely new physical interpretation was needed, namely, quantum mechanics. At first, the laws of quantum mechanics seemed to reveal fundamental limits to the accuracy of physical measurements. Concepts like the Heisenberg uncertainty principle, which imposes intrinsic fluctuations on the values of non-commuting observables, and the wavefunction collapse, responsible for the randomization of a system configuration after performing a measurement, appeared to be at odds with the requirement of deterministic consistency that is paramount for metrological purposes. Nevertheless, quantum-based systems are today acknowledged as the most stable and reliable metrological tools, as they can be strongly intertwined with fundamental constants. Exquisitely quantum-mechanical phenomena such as the ac Josephson effect 2 and the quantum Hall effect 3 have paved the way towards new and more reliable reference standards for the units of voltage and resistance, respectively.Major efforts are currently ongoing to re-define the unit of electrical current, the ampere (A), in terms of the elementary charge, e, by means of quantum technologies 4,5 . A practical implementation of this standard may be the electron pump, a device in which a quantum phenomenon, namely tunnelling, and classical Coulomb repulsion, are combined to control the transfer of an integer number of elementary charges. This device ideally generates a quantized output current, I P = nef , where n is an integer and f is the frequency of an external periodic drive. Several enabling technologies have already been developed including metal/oxide tunnel barrier devices 6,7 , normal-metal/superconductor turnstiles 8,9 , graphene double quantum dots 10 , donor-based pumps 11-13 , silicon-based quantum dot pumps 14-18 and GaAs-based quantum dot pumps [19][20][21][22][23][24][25][26][27] . To date, the latter scheme provides the lowest uncertainty of 1.2 parts per million (ppm) yielding current in excess o...

show abstract

mentioning

confidence: 99%

An Accurate Single-Electron Pump Based on a Highly Tunable Silicon Quantum Dot

et al. 2014

View full text Add to dashboard Cite

show abstract

“…This inhibits charge fluctuations due to disorder and offers well-defined spin-qubits ('static' qubits) which can be manipulated using electric fields, magnetic fields and their mutual Coulomb interaction. Single conduction electrons ('flying' qubits) can be added one at a time to semiconducting single-wall nanotubes, using a turnstile device [68]. They may also be selected for their spin orientation, using a magnetic contact, a quantum-dot filter [69] or a Zener filter [70].…”

Section: Static and Flying Qubits In Nanotubesmentioning

confidence: 99%

Towards a fullerene-based quantum computer

Benjamin

Ardavan

Briggs

et al. 2006

J. Phys.: Condens. Matter

174

141

View full text Add to dashboard Cite

Abstract. Molecular structures appear to be natural candidates for a quantum technology: individual atoms can support quantum superpositions for long periods, and such atoms can in principle be embedded in a permanent molecular scaffolding to form an array. This would be true nanotechnology, with dimensions of order of a nanometre. However, the challenges of realising such a vision are immense. One must identify a suitable elementary unit and demonstrate its merits for qubit storage and manipulation, including input / output. These units must then be formed into large arrays corresponding to an functional quantum architecture, including a mechanism for gate operations. Here we report our efforts, both experimental and theoretical, to create such a technology based on endohedral fullerenes or 'buckyballs'. We describe our successes with respect to these criteria, along with the obstacles we are currently facing and the questions that remain to be addressed.

show abstract

“…However, in systems of mesoscopic scale a dc current can be generated even at zero bias. This captivating quantum coherent effect is called quantum charge pumping [1,2,3] and it is of considerable interest both theoretically [1,2,3,4,5,6,7,8] and experimentally [9,10]. A device capable of providing such effect is called a quantum pump and typically involves the cyclic change of two device-control parameters with a frequency ω 0 .…”

Section: Introductionmentioning

confidence: 99%

Mono-parametric quantum charge pumping: Interplay between spatial interference and photon-assisted tunneling

2005

View full text Add to dashboard Cite

We analyze quantum charge pumping in an open ring with a dot embedded in one of its arms. We show that cyclic driving of the dot levels by a single parameter leads to a pumped current when a static magnetic flux is simultaneously applied to the ring. Based on the computation of the Floquet-Green's functions, we show that for low driving frequencies ω0, the interplay between the spatial interference through the ring plus photon-assisted tunneling gives an average direct current (dc) which is proportional to ω 2 0 . The direction of the pumped current can be reversed by changing the applied magnetic field.

show abstract

Quantized current in a quantum-dot turnstile using oscillating tunnel barriers

Cited by 488 publications

References 10 publications

An Accurate Single-Electron Pump Based on a Highly Tunable Silicon Quantum Dot

An Accurate Single-Electron Pump Based on a Highly Tunable Silicon Quantum Dot

Towards a fullerene-based quantum computer

Mono-parametric quantum charge pumping: Interplay between spatial interference and photon-assisted tunneling

Contact Info

Product

Resources

About