Accuracy evaluation and mechanism crossover of single-electron transfer in Si tunable-barrier turnstiles

Yamahata, Gento; Nishiguchi, Katsuhiko; Fujiwara, Akira

doi:10.1103/physrevb.89.165302

Cited by 30 publications

(57 citation statements)

References 25 publications

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“…4(c), inset) and also a thermal equilibrium model. 9,11 The decay cascade model yielded a better fit, as was also found at the much lower temperature of 25 mK. 9 The plateaus are considerably sharper using the slow loading pulse, consistent with pumped current measurements in which the rise time (proportional to the inverse of the pumping frequency) was varied in the 1 À 10 ns range.…”

supporting

confidence: 51%

“…Recently, DC measurements 8 have shown that $6 Â 10 8 electrons per second can be transferred through a QD with an average error rate as low as 2 Â 10 À7 . To probe the individual probabilities P n , mesoscopic charge detectors need to be used to measure the number of electrons pumped onto charge sensing islands, [9][10][11][12] with the lowest reported error probability, 10 À4 , achieved in a silicon QD pump.…”

mentioning

confidence: 99%

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High-resolution error detection in the capture process of a single-electron pump

Giblin

See

A.Petrie

et al. 2016

Applied Physics Letters

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The dynamic capture of electrons in a semiconductor quantum dot (QD) by raising a potential barrier is a crucial stage in metrological quantized charge pumping. In this work, we use a quantum point contact (QPC) charge sensor to study errors in the electron capture process of a QD formed in a GaAs heterostructure. Using a two-step measurement protocol to compensate for 1/f noise in the QPC current, and repeating the protocol more than 10 6 times, we are able to resolve errors with probabilities of order 10 −6 . For the studied sample, one-electron capture is affected by errors in ∼ 30 out of every million cycles, while two-electron capture was performed more than 10 6 times with only one error. For errors in one-electron capture, we detect both failure to capture an electron, and capture of two electrons. Electron counting measurements are a valuable tool for investigating non-equilibrium charge capture dynamics, and necessary for validating the metrological accuracy of semiconductor electron pumps.

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supporting

confidence: 51%

mentioning

confidence: 99%

High-resolution error detection in the capture process of a single-electron pump

Giblin

See

A.Petrie

et al. 2016

Applied Physics Letters

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“…In addition, it is valuable to also fit the characteristics using an equation based on the generalized grand canonical distribution (thermal equilibrium limit)163334:…”

Section: Resultsmentioning

confidence: 99%

High-accuracy current generation in the nanoampere regime from a silicon single-trap electron pump

Yamahata

Giblin

Kataoka

et al. 2017

Sci Rep

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A gigahertz single-electron (SE) pump with a semiconductor charge island is promising for a future quantum current standard. However, high-accuracy current in the nanoampere regime is still difficult to achieve because the performance of SE pumps tends to degrade significantly at frequencies exceeding 1 GHz. Here, we demonstrate robust SE pumping via a single-trap level in silicon up to 7.4 GHz, at which the pumping current exceeds 1 nA. An accuracy test with an uncertainty of about one part per million (ppm) reveals that the pumping current deviates from the ideal value by only about 20 ppm at the flattest part of the current plateau. This value is two orders of magnitude better than the best one reported in the nanoampere regime. In addition, the pumping accuracy is almost unchanged up to 7.4 GHz, probably due to strong electron confinement in the trap. These results indicate that trap-mediated SE pumping is promising for achieving the practical operation of the quantum current standard.

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“…Understanding ultrafast coherent electron dynamics is necessary for application of a single-electron source to metrological standards 1 , quantum information processing 2 , including electron quantum optics 3 , and quantum sensing 4,5 .…”

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confidence: 99%

Picosecond coherent electron motion in a silicon single-electron source

et al. 2019

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Understanding ultrafast coherent electron dynamics is necessary for application of a single-electron source to metrological standards 1 , quantum information processing 2 , including electron quantum optics 3 , and quantum sensing 4,5 .While the dynamics of an electron emitted from the source has been extensively studied 6-11 , there is as yet no study of the dynamics inside the source. This is because the speed of the internal dynamics is typically higher than 100 GHz, beyond state-of-the-art experimental bandwidth 2 . Here, we theoretically and experimentally demonstrate that the internal dynamics in a silicon singleelectron source comprising a dynamic quantum dot can be detected, utilising a resonant level with which the dynamics is read out as gate-dependent current oscillations. Our experimental observation and simulation with realistic parameters show that an electron wave packet spatially oscillates quantum-coherently at ∼ 200 GHz inside the source. Our results will lead to a protocol for detecting such fast dynamics in a cavity and offer a means of engineering electron wave packets 12 . This could allow high-accuracy current sources [13][14][15][16] , high-resolution and high-speed electromagnetic-field sensing 4 , and high-fidelity initialisation of flying qubits 17,18 .Owing to recent demonstrations of high-accuracy GHz operation 13-16 , a single-electron pump with a tunable-barrier quantum dot (QD) becomes promising for application to ondemand single-electron sources 1 . Because of the fast dynamic movement of the QD, there can occur nontrivial electron dynamics, such as non-adiabatic excitation 19 and subsequent coherent time evolution. While the non-adiabatic excitation could degrade the pumping accuracy, a spatial movement of an electron wave packet due to the coherent time evolution can be used for engineering a wave packet emitted from the QD 12 , which could make possible electron quantum optics experiments and high-speed quantum sensing with high resolution.In addition, understanding of the fast electron dynamics could offer insight into quantum computing with QDs. However, the existing standard measurement technique 20-22 does not have enough bandwidth to detect fast dynamics beyond 100 GHz. In order to overcome the limitation and detect the fast dynamics in the QD, we use a temporal change in a tunnel rate between a resonant level in a tunnel barrier and a QD, which is induced by the dynamic change of the QD potential.First of all, we explain how coherent oscillations of an electron in a single-electron pump 2 occur. A single-electron pump with a tunable-barrier QD consists of the entrance (Fig. 1a, left) and exit (right) potential barriers, formed by applying gate voltages V ent and V exit , respectively 23 . An AC voltage V ac (t) with frequency f in is added to dynamically tune the entrance barrier. The QD energy level is also tuned owing to the cross coupling. When the energy level E qd n (n = 1, 2, · · ·) of the QD with n electrons is lower than the Fermi level E f , electrons can be load...

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Accuracy evaluation and mechanism crossover of single-electron transfer in Si tunable-barrier turnstiles

Cited by 30 publications

References 25 publications

High-resolution error detection in the capture process of a single-electron pump

High-resolution error detection in the capture process of a single-electron pump

High-accuracy current generation in the nanoampere regime from a silicon single-trap electron pump

Picosecond coherent electron motion in a silicon single-electron source

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