Double-Dot Quantum Ratchet Driven by an Independently Biased Quantum Point Contact

Khrapai, V. S.; Ludwig, Stefan; Kotthaus, J. P.; Tranitz, Hans-Peter; Wegscheider, Werner

doi:10.1103/physrevlett.97.176803

Cited by 125 publications

(158 citation statements)

References 21 publications

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“…Interactively coupled mesoscopic and nanoscale circuits, such as quantum wires (Debray et al, 2000(Debray et al, , 2001Laroche et al, 2011;Morimoto et al, 2003;Yamamoto et al, 2006), quantum dots (Aguado and Kouwenhoven, 2000;Onac et al, 2006) or point contacts (Khrapai et al, 2006(Khrapai et al, , 2007, provided new fruitful ways of studying Coulomb drag phenomena and revealed a plethora of interesting physics. These devices typically have dimensions smaller than the temperature length L T = v F /T and voltage-related length scale L V = v F /(eV ), and differ substantially from their two-dimensional quantumwell counterparts in several important ways.…”

Section: A Quantum Dots and Quantum Point Contactsmentioning

confidence: 99%

Coulomb drag

2016

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Coulomb drag is a transport phenomenon whereby long-range Coulomb interaction between charge carriers in two closely spaced but electrically isolated conductors induces a voltage (or, in a closed circuit, a current) in one of the conductors when an electrical current is passed through the other. The magnitude of the effect depends on the exact nature of the charge carriers and microscopic, many-body structure of the electronic systems in the two conductors. Drag measurements have become part of the standard toolbox in condensed matter physics that can be used to study fundamental properties of diverse physical systems including semiconductor heterostructures, graphene, quantum wires, quantum dots, and optical cavities.

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Section: A Quantum Dots and Quantum Point Contactsmentioning

confidence: 99%

Coulomb drag

2016

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“…The QPC bias is chosen sufficiently small to avoid back-action on the QD. 19,20 The QD is coupled to source and drain electrodes via two tunneling barriers which can be separately controlled with gate voltages V G1 and V G2 . These gates are also used to tune the number of electrons on the QD.…”

Section: Figmentioning

confidence: 99%

High-order cumulants in the counting statistics of asymmetric quantum dots

Fricke

Hohls

Sethubalasubramanian

et al. 2010

Applied Physics Letters

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Measurements of single electron tunneling through a quantum dot using a quantum point contact as charge detector have been performed for very long time traces with very large event counts. This large statistical basis is used for a detailed examination of the counting statistics for varying symmetry of the quantum dot system. From the measured statistics we extract high order cumulants describing the distribution. Oscillations of the high order cumulants are observed when varying the symmetry. We compare this behavior to the observed oscillation in time dependence and show that the variation of both system variables lead to the same kind of oscillating response.

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“…The process induces a current flow through the system. Since the detuning δ may be varied continuously by applying appropriate gate voltages, the absorbtion energy is fully tunable.The scheme is experimentally challenging, due to low current levels and fast relaxation processes between the QDs [10]. Here, we show that these problems can be overcome by using time-resolved charge-detection techniques to detect single electrons tunneling into and out of the DQD.…”

mentioning

confidence: 99%

Frequency-Selective Single-Photon Detection Using a Double Quantum Dot

et al. 2007

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We use a double quantum dot as a frequency-tunable on-chip microwave detector to investigate the radiation from electron shot-noise in a near-by quantum point contact. The device is realized by monitoring the inelastic tunneling of electrons between the quantum dots due to photon absorption. The frequency of the absorbed radiation is set by the energy separation between the dots, which is easily tuned with gate voltages. Using time-resolved charge detection techniques, we can directly relate the detection of a tunneling electron to the absorption of a single photon.The interplay between quantum optics and mesoscopic physics opens up new horizons for investigating radiation produced in nanoscale conductors [1,2]. Microwave photons emitted from quantum conductors are predicted to show non-classical behavior such as anti-bunching [3] and entanglement [4]. Experimental investigations of such systems require sensitive, high-bandwidth detectors operating at microwave-frequency [5]. On-chip detection schemes, with the device and detector being strongly capacitively coupled, offer advantages in terms of sensitivity and large bandwidths. In previous work, the detection mechanism was implemented utilizing photon-assisted tunneling in a superconductor-insulator-superconductor junction [6,7] or in a single quantum dot (QD) [8].Aguado and Kouwenhoven proposed to use a double quantum dot (DQD) as a frequency-tunable quantum noise detector [9]. The idea is sketched in Fig. 1(a), showing the energy levels of the DQD together with a quantum point contact (QPC) acting as a noise source. The DQD is operated with a fixed detuning δ between the electrochemical potentials of the left and right QD. If the system absorbs an energy E = δ from the environment, the electron in QD1 is excited to QD2. This electron may leave to the drain lead, a new electron enters from the source contact and the cycle can be repeated. The process induces a current flow through the system. Since the detuning δ may be varied continuously by applying appropriate gate voltages, the absorbtion energy is fully tunable.The scheme is experimentally challenging, due to low current levels and fast relaxation processes between the QDs [10]. Here, we show that these problems can be overcome by using time-resolved charge-detection techniques to detect single electrons tunneling into and out of the DQD. Apart from giving higher sensitivity than conventional current measurement techniques, the method also allows us to directly relate a single-electron tunneling event to the absorbtion of a single photon. The system can thus be viewed as a frequency-selective single- * Electronic address: simongus@phys.ethz.ch

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Double-Dot Quantum Ratchet Driven by an Independently Biased Quantum Point Contact

Cited by 125 publications

References 21 publications

Coulomb drag

Coulomb drag

High-order cumulants in the counting statistics of asymmetric quantum dots

Frequency-Selective Single-Photon Detection Using a Double Quantum Dot

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