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32

Sep 19, 2013
09/13

by
O. Entin-Wohlman; A. Aharony; V. Kashcheyevs

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Recent theoretical calculations, demonstrating that quantized charge transfer due to adiabatically modulated potentials in mesoscopic devices can result purely from the interference of the electron wave functions (without invoking electron-electron interactions) are reviewed: (1) A new formula is derived for the pumped charge Q (per period); It reproduces the Brouwer formula without a bias, and also yields the effect of the modulating potential on the Landauer formula in the presence of a bias....

Source: http://arxiv.org/abs/cond-mat/0208069v1

41
41

Sep 21, 2013
09/13

by
V. N. Kuzovkov; V. Kashcheyevs; W. von Niessen

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We reply to comments by P.Marko$\breve{s}$, L.Schweitzer and M.Weyrauch [preceding paper] on our recent paper [J. Phys.: Condens. Matter 63, 13777 (2002)]. We demonstrate that our quite different viewpoints stem for the different physical assumptions made prior to the choice of the mathematical formalism. The authors of the Comment expect \emph{a priori} to see a single thermodynamic phase while our approach is capable of detecting co-existence of distinct pure phases. The limitations of the...

Source: http://arxiv.org/abs/cond-mat/0402468v1

29
29

Sep 18, 2013
09/13

by
V. N. Kuzovkov; W. von Niessen; V. Kashcheyevs; O. Hein

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The Anderson localization problem in one and two dimensions is solved analytically via the calculation of the generalized Lyapunov exponents. This is achieved by making use of signal theory. The phase diagram can be analyzed in this way. In the one dimensional case all states are localized for arbitrarily small disorder in agreement with existing theories. In the two dimensional case for larger energies and large disorder all states are localized but for certain energies and small disorder...

Source: http://arxiv.org/abs/cond-mat/0212036v1

32
32

Sep 23, 2013
09/13

by
V. Kashcheyevs; C. Karrasch; T. Hecht; A. Weichselbaum; V. Meden; A. Schiller

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Understanding the charging of exceptionally narrow levels in quantum dots in the presence of interactions remains a challenge within mesoscopic physics. We address this fundamental question in the generic model of a narrow level capacitively coupled to a broad one. Using bosonization we show that for arbitrary capacitive coupling charging can be described by an analogy to the magnetization in the anisotropic Kondo model, featuring a low-energy crossover scale that depends in a power-law fashion...

Source: http://arxiv.org/abs/0810.2538v2

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46

Sep 22, 2013
09/13

by
B. Kaestner; Ch. Leicht; V. Kashcheyevs; K. Pierz; U. Siegner; H. W. Schumacher

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We study single-parameter quantized charge pumping via a semiconductor quantum dot in high magnetic fields. The quantum dot is defined between two top gates in an AlGaAs/GaAs heterostructure. Application of an oscillating voltage to one of the gates leads to pumped current plateaus in the gate characteristic, corresponding to controlled transfer of integer multiples of electrons per cycle. In a perpendicular-to-plane magnetic field the plateaus become more pronounced indicating an improved...

Source: http://arxiv.org/abs/0811.1121v1

35
35

Sep 18, 2013
09/13

by
B. Kaestner; V. Kashcheyevs; G. Hein; K. Pierz; U. Siegner; H. W. Schumacher

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This paper investigates a scheme for quantized charge pumping based on single-parameter modulation. The device was realized in an AlGaAs-GaAs gated nanowire. We find a remarkable robustness of the quantized regime against variations in the driving signal, which increases with applied rf power. This feature together with its simple configuration makes this device a potential module for a scalable source of quantized current.

Source: http://arxiv.org/abs/0803.0869v1

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100

Jul 20, 2013
07/13

by
B. Kaestner; C. Leicht; P. Mirovsky; V. Kashcheyevs; E. V. Kurganova; U. Zeitler; K. Pierz; H. W. Schumacher

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We investigate a recently developed scheme for quantized charge pumping based on single-parameter modulation. The device was realized in an AlGaAl-GaAs gated nanowire. It has been shown theoretically that non-adiabaticity is fundamentally required to realize single-parameter pumping, while in previous multi-parameter pumping schemes it caused unwanted and less controllable currents. In this paper we demonstrate experimentally the constructive and destructive role of non-adiabaticity by...

Source: http://arxiv.org/abs/1007.2062v1

4
4.0

Jun 29, 2018
06/18

by
P. Clapera; J. Klochan; R. Lavieville; S. Barraud; L. Hutin; M. Sanquer; M. Vinet; A. Cinins; G. Barinovs; V. Kashcheyevs; X. Jehl

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We report CMOS-compatible quantized current sources (electron pumps) fabricated with nanowires (NWs) on 300 mm SOI wafers. Unlike other Al, GaAs or Si based metallic or semiconductor pumps, the fabrication does not rely on electron-beam lithography. The structure consists of two gates in series on the nanowire and the only difference with the SOI nanowire process lies in long (40 nm) nitride spacers. As a result a single, silicided island gets isolated between the gates and transport is...

Topics: Mesoscale and Nanoscale Physics, Condensed Matter

Source: http://arxiv.org/abs/1612.09547

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30

Sep 19, 2013
09/13

by
C. Leicht; P. Mirovsky; B. Kaestner; F. Hohls; V. Kashcheyevs; E. V. Kurganova; U. Zeitler; T. Weimann; K. Pierz; H. W. Schumacher

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We operate an on-demand source of single electrons in high perpendicular magnetic fields up to 30T, corresponding to a filling factor below 1/3. The device extracts and emits single charges at a tunable energy from and to a two-dimensional electron gas, brought into well defined integer and fractional quantum Hall (QH) states. It can therefore be used for sensitive electrical transport studies, e.g. of excitations and relaxation processes in QH edge states.

Source: http://arxiv.org/abs/1009.5897v1

6
6.0

Jun 27, 2018
06/18

by
J. Waldie; P. See; V. Kashcheyevs; J. P. Griffiths; I. Farrer; G. A. C. Jones; D. A. Ritchie; T. J. B. M. Janssen; M. Kataoka

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We report an experimental technique to measure and manipulate the arrival-time and energy distributions of electrons emitted from a semiconductor electron pump, operated as both a single-electron source and a two-electron source. Using an energy-selective detector whose transmission we control on picosecond timescales, we can measure directly the electron arrival-time distribution and we determine the upper-bound to the distribution width to be 30 ps. We study the effects of modifying the shape...

Topics: Condensed Matter, Mesoscale and Nanoscale Physics

Source: http://arxiv.org/abs/1503.07140

51
51

Jul 20, 2013
07/13

by
M. R. Buitelaar; V. Kashcheyevs; P. J. Leek; V. I. Talyanskii; C. G. Smith; D. Anderson; G. A. C. Jones; J. Wei; D. H. Cobden

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We investigate charge pumping in carbon nanotube quantum dots driven by the electric field of a surface acoustic wave. We find that at small driving amplitudes, the pumped current reverses polarity as the conductance is tuned through a Coulomb blockade peak using a gate electrode. We study the behavior as a function of wave amplitude, frequency and direction and develop a model in which our results can be understood as resulting from adiabatic charge redistribution between the leads and quantum...

Source: http://arxiv.org/abs/0804.3219v1

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51

Sep 18, 2013
09/13

by
B. Kaestner; V. Kashcheyevs; S. Amakawa; L. Li; M. D. Blumenthal; T. J. B. M. Janssen; G. Hein; K. Pierz; T. Weimann; U. Siegner; H. W. Schumacher

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Controlled charge pumping in an AlGaAs/GaAs gated nanowire by single-parameter modulation is studied experimentally and theoretically. Transfer of integral multiples of the elementary charge per modulation cycle is clearly demonstrated. A simple theoretical model shows that such a quantized current can be generated via loading and unloading of a dynamic quasi-bound state. It demonstrates that non-adiabatic blockade of unwanted tunnel events can obliterate the requirement of having at least two...

Source: http://arxiv.org/abs/0707.0993v1