1
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Kuo DMT. Effects of Coulomb Blockade on the Charge Transport through the Topological States of Finite Armchair Graphene Nanoribbons and Heterostructures. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:nano13111757. [PMID: 37299660 DOI: 10.3390/nano13111757] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 05/26/2023] [Accepted: 05/28/2023] [Indexed: 06/12/2023]
Abstract
In this study, we investigate the charge transport properties of semiconducting armchair graphene nanoribbons (AGNRs) and heterostructures through their topological states (TSs), with a specific focus on the Coulomb blockade region. Our approach employs a two-site Hubbard model that takes into account both intra- and inter-site Coulomb interactions. Using this model, we calculate the electron thermoelectric coefficients and tunneling currents of serially coupled TSs (SCTSs). In the linear response regime, we analyze the electrical conductance (Ge), Seebeck coefficient (S), and electron thermal conductance (κe) of finite AGNRs. Our results reveal that at low temperatures, the Seebeck coefficient is more sensitive to many-body spectra than electrical conductance. Furthermore, we observe that the optimized S at high temperatures is less sensitive to electron Coulomb interactions than Ge and κe. In the nonlinear response regime, we observe a tunneling current with negative differential conductance through the SCTSs of finite AGNRs. This current is generated by electron inter-site Coulomb interactions rather than intra-site Coulomb interactions. Additionally, we observe current rectification behavior in asymmetrical junction systems of SCTSs of AGNRs. Notably, we also uncover the remarkable current rectification behavior of SCTSs of 9-7-9 AGNR heterostructure in the Pauli spin blockade configuration. Overall, our study provides valuable insights into the charge transport properties of TSs in finite AGNRs and heterostructures. We emphasize the importance of considering electron-electron interactions in understanding the behavior of these materials.
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Affiliation(s)
- David M T Kuo
- Department of Electrical Engineering, National Central University, Chungli 320, Taiwan, China
- Department of Physics, National Central University, Chungli 320, Taiwan, China
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2
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Kuo DMT. Effects of metallic electrodes on the thermoelectric properties of zigzag graphene nanoribbons with periodic vacancies. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 35:305301. [PMID: 37068484 DOI: 10.1088/1361-648x/accdac] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 04/17/2023] [Indexed: 06/19/2023]
Abstract
We theoretically analyze the thermoelectric properties of graphene quantum dot arrays (GQDAs) with line- or surface-contacted metal electrodes. Such GQDAs are realized as zigzag graphene nanoribbons (ZGNRs) with periodic vacancies. Gaps and minibands are formed in these GQDAs, which can have metallic and semiconducting phases. The electronic states of the first conduction (valence) miniband with nonlinear dispersion may have long coherent lengths along the zigzag edge direction. With line-contacted metal electrodes, the GQDAs have the characteristics of serially coupled quantum dots (SCQDs) if the armchair edge atoms of the ZGNRs are coupled to the electrodes. By contrast, the GQDAs have the characteristics of parallel quantum dots if the zigzag edge atoms are coupled to the electrodes. The maximum thermoelectric power factors of SCQDs with line-contacted electrodes of Cu, Au, Pt, Pd, or Ti at room temperature were similar or greater than 0.186 nW K-1; their figures of merit were greater than three. GQDAs with line-contacted metal electrodes have much better thermoelectric performance than surface contacted metal electrodes.
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Affiliation(s)
- David M T Kuo
- Department of Electrical Engineering and Department of Physics, National Central University, Chungli 320, Taiwan
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3
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Haldar S, Havir H, Khan W, Lehmann S, Thelander C, Dick KA, Maisi VF. Energetics of Microwaves Probed by Double Quantum Dot Absorption. PHYSICAL REVIEW LETTERS 2023; 130:087003. [PMID: 36898111 DOI: 10.1103/physrevlett.130.087003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 01/24/2023] [Indexed: 06/18/2023]
Abstract
We explore the energetics of microwaves interacting with a double quantum dot photodiode and show wave-particle aspects in photon-assisted tunneling. The experiments show that the single-photon energy sets the relevant absorption energy in a weak-drive limit, which contrasts the strong-drive limit where the wave amplitude determines the relevant-energy scale and opens up microwave-induced bias triangles. The threshold condition between these two regimes is set by the fine-structure constant of the system. The energetics are determined here with the detuning conditions of the double dot system and stopping-potential measurements that constitute a microwave version of the photoelectric effect.
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Affiliation(s)
- Subhomoy Haldar
- NanoLund and Solid State Physics, Lund University, Box 118, 22100 Lund, Sweden
| | - Harald Havir
- NanoLund and Solid State Physics, Lund University, Box 118, 22100 Lund, Sweden
| | - Waqar Khan
- NanoLund and Solid State Physics, Lund University, Box 118, 22100 Lund, Sweden
- Center for Analysis and Synthesis, Lund University, Box 124, 22100 Lund, Sweden
| | - Sebastian Lehmann
- NanoLund and Solid State Physics, Lund University, Box 118, 22100 Lund, Sweden
| | - Claes Thelander
- NanoLund and Solid State Physics, Lund University, Box 118, 22100 Lund, Sweden
| | - Kimberly A Dick
- NanoLund and Solid State Physics, Lund University, Box 118, 22100 Lund, Sweden
- Center for Analysis and Synthesis, Lund University, Box 124, 22100 Lund, Sweden
| | - Ville F Maisi
- NanoLund and Solid State Physics, Lund University, Box 118, 22100 Lund, Sweden
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4
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Sarkar S, Dubi Y. Emergence and Dynamical Stability of a Charge Time-Crystal in a Current-Carrying Quantum Dot Simulator. NANO LETTERS 2022; 22:4445-4451. [PMID: 35580301 DOI: 10.1021/acs.nanolett.2c00976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Periodically driven open quantum systems that never thermalize exhibit a discrete time-crystal behavior, a nonequilibrium quantum phenomenon that has shown promise in quantum information processing applications. Measurements of time-crystallinity are currently limited to (magneto-) optical experiments in atom-cavity systems and spin-systems making it an indirect measurement. We theoretically show that time-crystallinity can be measured directly in the charge-current from a spin-less Hubbard ladder, which can be simulated on a quantum-dot array. We demonstrate that one can dynamically tune the system out and then back on a time-crystal phase, proving its robustness against external forcings. These findings motivate further theoretical and experimental efforts to simulate the time-crystal phenomena in current-carrying nanoscale systems.
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Affiliation(s)
- Subhajit Sarkar
- Department of Chemistry, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
- School of Electrical and Computer Engineering, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Yonatan Dubi
- Department of Chemistry, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
- Ilse Katz Center for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
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5
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Efficient and continuous microwave photoconversion in hybrid cavity-semiconductor nanowire double quantum dot diodes. Nat Commun 2021; 12:5130. [PMID: 34446735 PMCID: PMC8390526 DOI: 10.1038/s41467-021-25446-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 08/11/2021] [Indexed: 11/30/2022] Open
Abstract
Converting incoming photons to electrical current is the key operation principle of optical photodetectors and it enables a host of emerging quantum information technologies. The leading approach for continuous and efficient detection in the optical domain builds on semiconductor photodiodes. However, there is a paucity of efficient and continuous photon detectors in the microwave regime, because photon energies are four to five orders of magnitude lower therein and conventional photodiodes do not have that sensitivity. Here we tackle this gap and demonstrate how microwave photons can be efficiently and continuously converted to electrical current in a high-quality, semiconducting nanowire double quantum dot resonantly coupled to a cavity. In particular, in our photodiode device, an absorbed photon gives rise to a single electron tunneling through the double dot, with a conversion efficiency reaching 6%. Efficient conversion of microwave photons into electrical current would enable several applications in quantum technologies, especially if one could step outside of the gated-time regime. Here, the authors demonstrate continuous-time microwave photoconversion in double quantum dots with 6% efficiency.
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6
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Dorsch S, Svilans A, Josefsson M, Goldozian B, Kumar M, Thelander C, Wacker A, Burke A. Heat Driven Transport in Serial Double Quantum Dot Devices. NANO LETTERS 2021; 21:988-994. [PMID: 33459021 PMCID: PMC7875509 DOI: 10.1021/acs.nanolett.0c04017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 01/12/2021] [Indexed: 06/12/2023]
Abstract
Studies of thermally induced transport in nanostructures provide access to an exciting regime where fluctuations are relevant, enabling the investigation of fundamental thermodynamic concepts and the realization of thermal energy harvesters. We study a serial double quantum dot formed in an InAs/InP nanowire coupled to two electron reservoirs. By means of a specially designed local metallic joule-heater, the temperature of the phonon bath in the vicinity of the double quantum dot can be enhanced. This results in phonon-assisted transport, enabling the conversion of local heat into electrical power in a nanosized heat engine. Simultaneously, the electron temperatures of the reservoirs are affected, resulting in conventional thermoelectric transport. By detailed modeling and experimentally tuning the interdot coupling, we disentangle both effects. Furthermore, we show that phonon-assisted transport is sensitive to excited states. Our findings demonstrate the versatility of our design to study fluctuations and fundamental nanothermodynamics.
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Affiliation(s)
- Sven Dorsch
- Solid
State Physics and NanoLund, Lund University, Box 118, SE-221 00 Lund, Sweden
| | - Artis Svilans
- Solid
State Physics and NanoLund, Lund University, Box 118, SE-221 00 Lund, Sweden
| | - Martin Josefsson
- Solid
State Physics and NanoLund, Lund University, Box 118, SE-221 00 Lund, Sweden
| | - Bahareh Goldozian
- Mathematical
Physics and NanoLund, Lund University, Box 118, SE-221 00 Lund, Sweden
| | - Mukesh Kumar
- Solid
State Physics and NanoLund, Lund University, Box 118, SE-221 00 Lund, Sweden
| | - Claes Thelander
- Solid
State Physics and NanoLund, Lund University, Box 118, SE-221 00 Lund, Sweden
| | - Andreas Wacker
- Mathematical
Physics and NanoLund, Lund University, Box 118, SE-221 00 Lund, Sweden
| | - Adam Burke
- Solid
State Physics and NanoLund, Lund University, Box 118, SE-221 00 Lund, Sweden
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7
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Ghirri A, Cornia S, Affronte M. Microwave Photon Detectors Based on Semiconducting Double Quantum Dots. SENSORS (BASEL, SWITZERLAND) 2020; 20:s20144010. [PMID: 32707648 PMCID: PMC7412044 DOI: 10.3390/s20144010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 07/01/2020] [Accepted: 07/15/2020] [Indexed: 05/14/2023]
Abstract
Detectors of microwave photons find applications in different fields ranging from security to cosmology. Due to the intrinsic difficulties related to the detection of vanishingly small energy quanta ℏ ω , significant portions of the microwave electromagnetic spectrum are still uncovered by suitable techniques. No prevailing technology has clearly emerged yet, although different solutions have been tested in different contexts. Here, we focus on semiconductor quantum dots, which feature wide tunability by external gate voltages and scalability for large architectures. We discuss possible pathways for the development of microwave photon detectors based on photon-assisted tunneling in semiconducting double quantum dot circuits. In particular, we consider implementations based on either broadband transmission lines or resonant cavities, and we discuss how developments in charge sensing techniques and hybrid architectures may be beneficial for the development of efficient photon detectors in the microwave range.
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Affiliation(s)
- Alberto Ghirri
- Istituto Nanoscienze-CNR, via Campi 213/a, 41125 Modena, Italy; (S.C.); (M.A.)
- Correspondence:
| | - Samuele Cornia
- Istituto Nanoscienze-CNR, via Campi 213/a, 41125 Modena, Italy; (S.C.); (M.A.)
- Dipartimento di Scienze Fisiche, Informatiche e Matematiche, Università di Modena e Reggio Emilia, via Campi 213/a, 41125 Modena, Italy
| | - Marco Affronte
- Istituto Nanoscienze-CNR, via Campi 213/a, 41125 Modena, Italy; (S.C.); (M.A.)
- Dipartimento di Scienze Fisiche, Informatiche e Matematiche, Università di Modena e Reggio Emilia, via Campi 213/a, 41125 Modena, Italy
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8
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Single-Shot Readout Performance of Two Heterojunction-Bipolar-Transistor Amplification Circuits at Millikelvin Temperatures. Sci Rep 2019; 9:16976. [PMID: 31740683 PMCID: PMC6861249 DOI: 10.1038/s41598-019-52868-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 09/29/2019] [Indexed: 11/30/2022] Open
Abstract
High-fidelity single-shot readout of spin qubits requires distinguishing states much faster than the T1 time of the spin state. One approach to improving readout fidelity and bandwidth (BW) is cryogenic amplification, where the signal from the qubit is amplified before noise sources are introduced and room-temperature amplifiers can operate at lower gain and higher BW. We compare the performance of two cryogenic amplification circuits: a current-biased heterojunction bipolar transistor circuit (CB-HBT), and an AC-coupled HBT circuit (AC-HBT). Both circuits are mounted on the mixing-chamber stage of a dilution refrigerator and are connected to silicon metal oxide semiconductor (Si-MOS) quantum dot devices on a printed circuit board (PCB). The power dissipated by the CB-HBT ranges from 0.1 to 1 μW whereas the power of the AC-HBT ranges from 1 to 20 μW. Referred to the input, the noise spectral density is low for both circuits, in the 15 to 30 fA/\documentclass[12pt]{minimal}
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\begin{document}$$\sqrt{{\bf{Hz}}}$$\end{document}Hz range. The charge sensitivity for the CB-HBT and AC-HBT is 330 μe/\documentclass[12pt]{minimal}
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\begin{document}$$\sqrt{{\bf{Hz}}}$$\end{document}Hz and 400 μe/\documentclass[12pt]{minimal}
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\begin{document}$$\sqrt{{\bf{Hz}}}$$\end{document}Hz, respectively. For the single-shot readout performed, less than 10 μs is required for both circuits to achieve bit error rates below 10−3, which is a putative threshold for quantum error correction.
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9
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Bülte J, Bednorz A, Bruder C, Belzig W. Noninvasive Quantum Measurement of Arbitrary Operator Order by Engineered Non-Markovian Detectors. PHYSICAL REVIEW LETTERS 2018; 120:140407. [PMID: 29694141 DOI: 10.1103/physrevlett.120.140407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 10/30/2017] [Indexed: 06/08/2023]
Abstract
The development of solid-state quantum technologies requires the understanding of quantum measurements in interacting, nonisolated quantum systems. In general, a permanent coupling of detectors to a quantum system leads to memory effects that have to be taken into account in interpreting the measurement results. We analyze a generic setup of two detectors coupled to a quantum system and derive a compact formula in the weak-measurement limit that interpolates between an instantaneous (text-book type) and almost continuous-detector dynamics-dependent-measurement. A quantum memory effect that we term "system-mediated detector-detector interaction" is crucial to observe noncommuting observables simultaneously. Finally, we propose a mesoscopic double-dot detector setup in which the memory effect is tunable and that can be used to explore the transition to non-Markovian quantum measurements experimentally.
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Affiliation(s)
- Johannes Bülte
- Fachbereich Physik, Universität Konstanz, D-78457 Konstanz, Germany
| | - Adam Bednorz
- Faculty of Physics, University of Warsaw, Pasteura 5, PL02-093 Warsaw, Poland
| | - Christoph Bruder
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Wolfgang Belzig
- Fachbereich Physik, Universität Konstanz, D-78457 Konstanz, Germany
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10
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Crépieux A, Sahoo S, Duong TQ, Zamoum R, Lavagna M. Emission Noise in an Interacting Quantum Dot: Role of Inelastic Scattering and Asymmetric Coupling to the Reservoirs. PHYSICAL REVIEW LETTERS 2018; 120:107702. [PMID: 29570316 DOI: 10.1103/physrevlett.120.107702] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Indexed: 06/08/2023]
Abstract
A theory is developed for the emission noise at frequency ν in a quantum dot in the presence of Coulomb interactions and asymmetric couplings to the reservoirs. We give an analytical expression for the noise in terms of the various transmission amplitudes. Including the inelastic scattering contribution, it can be seen as the analog of the Meir-Wingreen formula for the current. A physical interpretation is given on the basis of the transmission of one electron-hole pair to the concerned reservoir where it emits an energy after recombination. We then treat the interactions by solving the self-consistent equations of motion for the Green functions. The results for the noise derivative versus eV show a zero value until eV=hν, followed by a Kondo peak in the Kondo regime, in good agreement with recent measurements in carbon nanotube quantum dots.
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Affiliation(s)
- A Crépieux
- Aix Marseille Univ, Université de Toulon, CNRS, CPT UMR 7332, 13288 Marseille, France
| | - S Sahoo
- Univ. Grenoble Alpes, CEA, INAC-Pheliqs, 38000 Grenoble, France
- Physics Department and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - T Q Duong
- Aix Marseille Univ, Université de Toulon, CNRS, CPT UMR 7332, 13288 Marseille, France
| | - R Zamoum
- Faculté des sciences et des sciences appliquées, Université de Bouira, rue Drissi Yahia, Bouira 10000, Algeria
| | - M Lavagna
- Univ. Grenoble Alpes, CEA, INAC-Pheliqs, 38000 Grenoble, France
- Centre National de la Recherche Scientifique-CNRS, 38042 Grenoble, France
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11
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Kohler S. Dispersive Readout of Adiabatic Phases. PHYSICAL REVIEW LETTERS 2017; 119:196802. [PMID: 29219518 DOI: 10.1103/physrevlett.119.196802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Indexed: 06/07/2023]
Abstract
We propose a protocol for the measurement of adiabatic phases of periodically driven quantum systems coupled to an open cavity that enables dispersive readout. It turns out that the cavity transmission exhibits peaks at frequencies determined by a resonance condition that involves the dynamical and the geometric phase. Since these phases scale differently with the driving frequency, one can determine them by fitting the peak positions to the theoretically expected behavior. For the derivation of the resonance condition and for a numerical study, we develop a Floquet theory for the dispersive readout of ac driven quantum systems. The feasibility is demonstrated for two test cases that generalize Landau-Zener-Stückelberg-Majorana interference to two-parameter driving.
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Affiliation(s)
- Sigmund Kohler
- Instituto de Ciencia de Materiales de Madrid, CSIC, E-28049 Madrid, Spain
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12
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Kaasbjerg K, Jauho AP. Correlated Coulomb Drag in Capacitively Coupled Quantum-Dot Structures. PHYSICAL REVIEW LETTERS 2016; 116:196801. [PMID: 27232031 DOI: 10.1103/physrevlett.116.196801] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Indexed: 06/05/2023]
Abstract
We study theoretically Coulomb drag in capacitively coupled quantum dots (CQDs)-a bias-driven dot coupled to an unbiased dot where transport is due to Coulomb mediated energy transfer drag. To this end, we introduce a master-equation approach that accounts for higher-order tunneling (cotunneling) processes as well as energy-dependent lead couplings, and identify a mesoscopic Coulomb drag mechanism driven by nonlocal multielectron cotunneling processes. Our theory establishes the conditions for a nonzero drag as well as the direction of the drag current in terms of microscopic system parameters. Interestingly, the direction of the drag current is not determined by the drive current, but by an interplay between the energy-dependent lead couplings. Studying the drag mechanism in a graphene-based CQD heterostructure, we show that the predictions of our theory are consistent with recent experiments on Coulomb drag in CQD systems.
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Affiliation(s)
- Kristen Kaasbjerg
- Center for Nanostructured Graphene (CNG), Department of Micro- and Nanotechnology, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Antti-Pekka Jauho
- Center for Nanostructured Graphene (CNG), Department of Micro- and Nanotechnology, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
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13
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Bischoff D, Eich M, Zilberberg O, Rössler C, Ihn T, Ensslin K. Measurement Back-Action in Stacked Graphene Quantum Dots. NANO LETTERS 2015; 15:6003-6008. [PMID: 26280388 DOI: 10.1021/acs.nanolett.5b02167] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We present an electronic transport experiment in graphene where both classical and quantum mechanical charge detector back-action on a quantum dot are investigated. The device consists of two stacked graphene quantum dots separated by a thin layer of boron nitride. This device is fabricated by van der Waals stacking and is equipped with separate source and drain contacts to both dots. By applying a finite bias to one quantum dot, a current is induced in the other unbiased dot. We present an explanation of the observed measurement-induced current based on strong capacitive coupling and energy dependent tunneling barriers, breaking the spatial symmetry in the unbiased system. This is a special feature of graphene-based quantum devices. The experimental observation of transport in classically forbidden regimes is understood by considering higher-order quantum mechanical back-action mechanisms.
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Affiliation(s)
- D Bischoff
- Solid State Physics Laboratory and ‡Institute for Theoretical Physics, ETH Zurich , 8093 Zurich, Switzerland
| | - M Eich
- Solid State Physics Laboratory and ‡Institute for Theoretical Physics, ETH Zurich , 8093 Zurich, Switzerland
| | - O Zilberberg
- Solid State Physics Laboratory and ‡Institute for Theoretical Physics, ETH Zurich , 8093 Zurich, Switzerland
| | - C Rössler
- Solid State Physics Laboratory and ‡Institute for Theoretical Physics, ETH Zurich , 8093 Zurich, Switzerland
| | - T Ihn
- Solid State Physics Laboratory and ‡Institute for Theoretical Physics, ETH Zurich , 8093 Zurich, Switzerland
| | - K Ensslin
- Solid State Physics Laboratory and ‡Institute for Theoretical Physics, ETH Zurich , 8093 Zurich, Switzerland
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14
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Li ZZ, Lam CH, You JQ. Probing Majorana bound states via counting statistics of a single electron transistor. Sci Rep 2015; 5:11416. [PMID: 26098973 PMCID: PMC4476256 DOI: 10.1038/srep11416] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 05/22/2015] [Indexed: 11/09/2022] Open
Abstract
We propose an approach for probing Majorana bound states (MBSs) in a nanowire via counting statistics of a nearby charge detector in the form of a single-electron transistor (SET). We consider the impacts on the counting statistics by both the local coupling between the detector and an adjacent MBS at one end of a nanowire and the nonlocal coupling to the MBS at the other end. We show that the Fano factor and the skewness of the SET current are minimized for a symmetric SET configuration in the absence of the MBSs or when coupled to a fermionic state. However, the minimum points of operation are shifted appreciably in the presence of the MBSs to asymmetric SET configurations with a higher tunnel rate at the drain than at the source. This feature persists even when varying the nonlocal coupling and the pairing energy between the two MBSs. We expect that these MBS-induced shifts can be measured experimentally with available technologies and can serve as important signatures of the MBSs.
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Affiliation(s)
- Zeng-Zhao Li
- Laboratory for Quantum Optics and Quantum Information, Beijing Computational Science Research Center, Beijing 100094, China.,Department of Applied Physics, Hong Kong Polytechnic University, Hung Hom, Hong Kong, China
| | - Chi-Hang Lam
- Department of Applied Physics, Hong Kong Polytechnic University, Hung Hom, Hong Kong, China
| | - J Q You
- Laboratory for Quantum Optics and Quantum Information, Beijing Computational Science Research Center, Beijing 100094, China
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15
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Parlavecchio O, Altimiras C, Souquet JR, Simon P, Safi I, Joyez P, Vion D, Roche P, Esteve D, Portier F. Fluctuation-dissipation relations of a tunnel junction driven by a quantum circuit. PHYSICAL REVIEW LETTERS 2015; 114:126801. [PMID: 25860764 DOI: 10.1103/physrevlett.114.126801] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Indexed: 06/04/2023]
Abstract
We derive fluctuation-dissipation relations for a tunnel junction driven through a resonator displaying strong quantum fluctuations. We find that the fluctuation-dissipation relations derived for classical external drives hold, provided the effect of the circuit's quantum fluctuations is incorporated into the modified nonlinear current voltage characteristics. We also demonstrate that all quantities measured under a time dependent bias can be reconstructed from their values measured under a dc bias using photoassisted tunneling relations. We confirm these predictions by implementing the circuit and measuring the dc current through the junction, its high frequency admittance, and its current noise at the frequency of the resonator.
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Affiliation(s)
- O Parlavecchio
- SPEC (UMR 3680 CEA-CNRS), CEA Saclay, 91191 Gif-sur-Yvette, France
| | - C Altimiras
- SPEC (UMR 3680 CEA-CNRS), CEA Saclay, 91191 Gif-sur-Yvette, France
| | - J-R Souquet
- Laboratoire de Physique des Solides, Université Paris-Sud, 91405 Orsay, France
| | - P Simon
- Laboratoire de Physique des Solides, Université Paris-Sud, 91405 Orsay, France
| | - I Safi
- Laboratoire de Physique des Solides, Université Paris-Sud, 91405 Orsay, France
| | - P Joyez
- SPEC (UMR 3680 CEA-CNRS), CEA Saclay, 91191 Gif-sur-Yvette, France
| | - D Vion
- SPEC (UMR 3680 CEA-CNRS), CEA Saclay, 91191 Gif-sur-Yvette, France
| | - P Roche
- SPEC (UMR 3680 CEA-CNRS), CEA Saclay, 91191 Gif-sur-Yvette, France
| | - D Esteve
- SPEC (UMR 3680 CEA-CNRS), CEA Saclay, 91191 Gif-sur-Yvette, France
| | - F Portier
- SPEC (UMR 3680 CEA-CNRS), CEA Saclay, 91191 Gif-sur-Yvette, France
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16
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Detecting noise with shot noise using on-chip photon detector. Nat Commun 2015; 6:6130. [PMID: 25625934 DOI: 10.1038/ncomms7130] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Accepted: 12/16/2014] [Indexed: 11/08/2022] Open
Abstract
The high-frequency radiation emitted by a quantum conductor presents a rising interest in quantum physics and condensed matter. However, its detection with microwave circuits is challenging. Here, we propose to use the photon-assisted shot noise for on-chip radiation detection. It is based on the low-frequency current noise generated by the partitioning of photon-excited electrons and holes, which are scattered inside the conductor. For a given electromagnetic coupling to the radiation, the photon-assisted shot noise response is shown to be independent on the nature and geometry of the quantum conductor used for the detection, up to a Fano factor, characterizing the type of scattering mechanism. Ordered in temperature or frequency range, from few tens of mK or GHz to several hundred of K or THz respectively, a wide variety of conductors can be used like Quantum Point Contacts (this work), diffusive metallic or semi-conducting films, graphene, carbon nanotubes and even molecule, opening new experimental opportunities in quantum physics.
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17
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Liu YY, Petersson KD, Stehlik J, Taylor JM, Petta JR. Photon emission from a cavity-coupled double quantum dot. PHYSICAL REVIEW LETTERS 2014; 113:036801. [PMID: 25083659 DOI: 10.1103/physrevlett.113.036801] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Indexed: 06/03/2023]
Abstract
We study a voltage biased InAs double quantum dot (DQD) that is coupled to a superconducting transmission line resonator. Inelastic tunneling in the DQD is mediated by electron phonon coupling and coupling to the cavity mode. We show that electronic transport through the DQD leads to photon emission from the cavity at a rate of 10 MHz. With a small cavity drive field, we observe a gain of up to 15 in the cavity transmission. Our results are analyzed in the context of existing theoretical models and suggest that it may be necessary to account for inelastic tunneling processes that proceed via simultaneous emission of a phonon and a photon.
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Affiliation(s)
- Y-Y Liu
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - K D Petersson
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - J Stehlik
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - J M Taylor
- Joint Quantum Institute/NIST, College Park, Maryland 20742, USA
| | - J R Petta
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
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18
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Kanazawa K, Sagawa T, Hayakawa H. Energy pumping in electrical circuits under avalanche noise. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 90:012115. [PMID: 25122259 DOI: 10.1103/physreve.90.012115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Indexed: 06/03/2023]
Abstract
We theoretically study energy pumping processes in an electrical circuit with avalanche diodes, where non-Gaussian athermal noise plays a crucial role. We show that a positive amount of energy (work) can be extracted by an external manipulation of the circuit in a cyclic way, even when the system is spatially symmetric. We discuss the properties of the energy pumping process for both quasistatic and finite-time cases, and analytically obtain formulas for the amounts of the work and the power. Our results demonstrate the significance of the non-Gaussianity in energetics of electrical circuits.
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Affiliation(s)
- Kiyoshi Kanazawa
- Yukawa Institute for Theoretical Physics, Kyoto University, Kitashirakawa-oiwake cho, Sakyo-ku, Kyoto 606-8502, Japan
| | - Takahiro Sagawa
- Department of Basic Science, The University of Tokyo, Komaba 3-8-1, Meguro-ku, Tokyo 153-8902, Japan
| | - Hisao Hayakawa
- Yukawa Institute for Theoretical Physics, Kyoto University, Kitashirakawa-oiwake cho, Sakyo-ku, Kyoto 606-8502, Japan
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19
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Altimiras C, Parlavecchio O, Joyez P, Vion D, Roche P, Esteve D, Portier F. Dynamical Coulomb blockade of shot noise. PHYSICAL REVIEW LETTERS 2014; 112:236803. [PMID: 24972223 DOI: 10.1103/physrevlett.112.236803] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Indexed: 06/03/2023]
Abstract
We observe the suppression of the finite frequency shot noise produced by a voltage biased tunnel junction due to its interaction with a single electromagnetic mode of high impedance. The tunnel junction is embedded in a λ/4 resonator containing a dense SQUID array providing it with a characteristic impedance in the kΩ range and a resonant frequency tunable in the 4-6 GHz range. Such high impedance gives rise to a sizable Coulomb blockade on the tunnel junction ( 30% reduction in the differential conductance) and allows an efficient measurement of the spectral density of the current fluctuations at the resonator frequency. The observed blockade of shot noise is found in agreement with an extension of the dynamical Coulomb blockade theory.
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Affiliation(s)
- Carles Altimiras
- Service de Physique de l'Etat Condensé (CNRS URA 2464), IRAMIS, CEA-Saclay, 91191 Gif-sur-Yvette, France
| | - Olivier Parlavecchio
- Service de Physique de l'Etat Condensé (CNRS URA 2464), IRAMIS, CEA-Saclay, 91191 Gif-sur-Yvette, France
| | - Philippe Joyez
- Service de Physique de l'Etat Condensé (CNRS URA 2464), IRAMIS, CEA-Saclay, 91191 Gif-sur-Yvette, France
| | - Denis Vion
- Service de Physique de l'Etat Condensé (CNRS URA 2464), IRAMIS, CEA-Saclay, 91191 Gif-sur-Yvette, France
| | - Patrice Roche
- Service de Physique de l'Etat Condensé (CNRS URA 2464), IRAMIS, CEA-Saclay, 91191 Gif-sur-Yvette, France
| | - Daniel Esteve
- Service de Physique de l'Etat Condensé (CNRS URA 2464), IRAMIS, CEA-Saclay, 91191 Gif-sur-Yvette, France
| | - Fabien Portier
- Service de Physique de l'Etat Condensé (CNRS URA 2464), IRAMIS, CEA-Saclay, 91191 Gif-sur-Yvette, France
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20
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Dorfman KE, Mukamel S. Indistinguishability and correlations of photons generated by quantum emitters undergoing spectral diffusion. Sci Rep 2014; 4:3996. [PMID: 24510121 PMCID: PMC3918844 DOI: 10.1038/srep03996] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 01/13/2014] [Indexed: 01/25/2023] Open
Abstract
Photon-based quantum information processing is based on manipulating multi photon interference. We focus on the Hong-Ou-Mandel (HOM) dip in the photon coincidence rate which provides a direct measure of interference of indistinguishable photons linked to their Bose statistics. The effect has been first observed with entangled photons generated by parametric down conversion and then extended to independent emitters. Fluctuations caused by coupling between emitters and a bath can erode the interference which causes the dip. Here we show how the magnitude and shape of the HOM dip is affected by spectral diffusion induced by coupling to a brownian oscillator bath. Conditions for maintaining and controlling the interference are specified.
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Affiliation(s)
| | - Shaul Mukamel
- University of California, Irvine, California 92697-2025
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21
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Li ZZ, Lam CH, Yu T, You JQ. Detector-induced backaction on the counting statistics of a double quantum dot. Sci Rep 2013; 3:3026. [PMID: 24149587 PMCID: PMC3805975 DOI: 10.1038/srep03026] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Accepted: 10/04/2013] [Indexed: 12/02/2022] Open
Abstract
Full counting statistics of electron transport is of fundamental importance for a deeper understanding of the underlying physical processes in quantum transport in nanoscale devices. The backaction effect from a detector on the nanoscale devices is also essential due to its inevitable presence in experiments. Here we investigate the backaction of a charge detector in the form of a quantum point contact (QPC) on the counting statistics of a biased double quantum dot (DQD). We show that this inevitable QPC-induced backaction can have profound effects on the counting statistics under certain conditions, e.g., changing the shot noise from being sub-Poissonian to super-Poissonian, and changing the skewness from being positive to negative. Also, we show that both Fano factor and skewness can be either enhanced or suppressed by increasing the energy difference between two single-dot levels of the DQD under the detector-induced backaction.
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Affiliation(s)
- Zeng-Zhao Li
- Beijing Computational Science Research Center, Beijing 100084, China
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22
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Müller T, Choi T, Hellmüller S, Ensslin K, Ihn T, Schön S. A circuit analysis of an in situ tunable radio-frequency quantum point contact. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2013; 84:083902. [PMID: 24007074 DOI: 10.1063/1.4817306] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
A detailed analysis of the tunability of a radio-frequency quantum point contact setup using a C - LCR circuit is presented. We calculate how the series capacitance influences resonance frequency and charge-detector resistance for which matching is achieved as well as the voltage and power delivered to the load. Furthermore, we compute the noise contributions in the system and compare our findings with measurements taken with an etched quantum point contact. While our considerations mostly focus on our specific choice of matching circuit, the discussion of the influence of source-to-load power transfer on the signal-to-noise ratio is valid generally.
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Affiliation(s)
- T Müller
- Solid State Physics Laboratory, ETH Zürich, 8093 Zürich, Switzerland
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23
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Taubert D, Schuh D, Wegscheider W, Ludwig S. Determination of energy scales in few-electron double quantum dots. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2011; 82:123905. [PMID: 22225229 DOI: 10.1063/1.3673003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The capacitive couplings between gate-defined quantum dots and their gates vary considerably as a function of applied gate voltages. The conversion between gate voltages and the relevant energy scales is usually performed in a regime of rather symmetric dot-lead tunnel couplings strong enough to allow direct transport measurements. Unfortunately, this standard procedure fails for weak and possibly asymmetric tunnel couplings, often the case in realistic devices. We have developed methods to determine the gate voltage to energy conversion accurately in the different regimes of dot-lead tunnel couplings and demonstrate strong variations of the conversion factors. Our concepts can easily be extended to triple quantum dots or even larger arrays.
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Affiliation(s)
- D Taubert
- Center for NanoScience and Fakultät für Physik, Ludwig-Maximilians-Universität München, Geschwister-Scholl-Platz 1, D-80539 München, Germany
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24
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Chen YF, Hover D, Sendelbach S, Maurer L, Merkel ST, Pritchett EJ, Wilhelm FK, McDermott R. Microwave photon counter based on Josephson junctions. PHYSICAL REVIEW LETTERS 2011; 107:217401. [PMID: 22181922 DOI: 10.1103/physrevlett.107.217401] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Revised: 07/12/2011] [Indexed: 05/27/2023]
Abstract
We describe a microwave photon counter based on the current-biased Josephson junction. The junction is tuned to absorb single microwave photons from the incident field, after which it tunnels into a classically observable voltage state. Using two such detectors, we have performed a microwave version of the Hanbury Brown-Twiss experiment at 4 GHz and demonstrated a clear signature of photon bunching for a thermal source. The design is readily scalable to tens of parallelized junctions, a configuration that would allow number-resolved counting of microwave photons.
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Affiliation(s)
- Y-F Chen
- Department of Physics, University of Wisconsin, Madison, 53706, USA
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25
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Filippone M, Le Hur K, Mora C. Giant charge relaxation resistance in the Anderson model. PHYSICAL REVIEW LETTERS 2011; 107:176601. [PMID: 22107549 DOI: 10.1103/physrevlett.107.176601] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Indexed: 05/31/2023]
Abstract
We investigate the dynamical charge response of the Anderson model viewed as a quantum RC circuit. Applying a low-energy effective Fermi liquid theory, a generalized Korringa-Shiba formula is derived at zero temperature, and the charge relaxation resistance is expressed solely in terms of static susceptibilities which are accessible by Bethe ansatz. We identify a giant charge relaxation resistance at intermediate magnetic fields related to the destruction of the Kondo singlet. The scaling properties of this peak are computed analytically in the Kondo regime. We also show that the resistance peak fades away at the particle-hole symmetric point.
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Affiliation(s)
- Michele Filippone
- Laboratoire Pierre Aigrain, École Normale Supérieure, Université Paris 7 Diderot, CNRS, 24 rue Lhomond, 75005 Paris, France
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26
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Huefner M, Schnez S, Kueng B, Ihn T, Reinwald M, Wegscheider W, Ensslin K. Mapping leakage currents in a nanostructure fabricated via local anodic oxidation. NANOTECHNOLOGY 2011; 22:295306. [PMID: 21693803 DOI: 10.1088/0957-4484/22/29/295306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The functionality of nanostructures fabricated via local anodic oxidation is limited by undesired leakage currents. We use low-temperature scanning gate microscopy to pin down the spatial position where leakage currents are most likely to occur. We show that leakage currents do not flow homogeneously along the complete barrier but at distinct weak points such as crossings of two oxide lines. These findings can be used to improve the design of such nanostructures.
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Affiliation(s)
- M Huefner
- Solid State Physics Laboratory, ETH Zürich, Zürich, Switzerland
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27
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Basset J, Bouchiat H, Deblock R. Emission and absorption quantum noise measurement with an on-chip resonant circuit. PHYSICAL REVIEW LETTERS 2010; 105:166801. [PMID: 21230992 DOI: 10.1103/physrevlett.105.166801] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Indexed: 05/30/2023]
Abstract
Using a quantum detector, a superconductor-insulator-superconductor junction, we probe separately the emission and absorption noise in the quantum regime of a superconducting resonant circuit at equilibrium. At low temperature the resonant circuit exhibits only absorption noise related to zero point fluctuations, whereas at higher temperature emission noise is also present. By coupling a Josephson junction, biased above the superconducting gap, to the same resonant circuit, we directly measure the noise power of quasiparticles tunneling through the junction at two resonance frequencies. It exhibits a strong frequency dependence, consistent with theoretical predictions.
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Affiliation(s)
- J Basset
- Laboratoire de Physique des Solides, Université Paris-Sud, CNRS, UMR 8502, F-91405 Orsay Cedex, France
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28
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29
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Petersson KD, Smith CG, Anderson D, Atkinson P, Jones GAC, Ritchie DA. Charge and spin state readout of a double quantum dot coupled to a resonator. NANO LETTERS 2010; 10:2789-2793. [PMID: 20698590 DOI: 10.1021/nl100663w] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
State readout is a key requirement for a quantum computer. For semiconductor-based qubit devices it is usually accomplished using a separate mesoscopic electrometer. Here we demonstrate a simple detection scheme in which a radio frequency resonant circuit coupled to a semiconductor double quantum dot is used to probe its charge and spin states. These results demonstrate a new noninvasive technique for measuring charge and spin states in quantum dot systems without requiring a separate mesoscopic detector.
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Affiliation(s)
- K D Petersson
- Cavendish Laboratory, JJ Thomson Road, Cambridge CB3 0HE, United Kingdom.
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30
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Schneider NL, Schull G, Berndt R. Optical probe of quantum shot-noise reduction at a single-atom contact. PHYSICAL REVIEW LETTERS 2010; 105:026601. [PMID: 20867722 DOI: 10.1103/physrevlett.105.026601] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2010] [Indexed: 05/13/2023]
Abstract
Visible and infrared light emitted at a Ag-Ag(111) junction has been investigated from tunneling to single-atom contact conditions with a scanning tunneling microscope. The light intensity varies in a highly nonlinear fashion with the conductance of the junction and exhibits a minimum at conductances close to the conductance quantum. The data are interpreted in terms of current noise at optical frequencies, which is characteristic of partially open transport channels.
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Affiliation(s)
- Natalia L Schneider
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, D-24098 Kiel, Germany
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31
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Gasser U, Gustavsson S, Küng B, Ensslin K, Ihn T. Phonon-mediated back-action of a charge readout on a double quantum dot. NANOTECHNOLOGY 2010; 21:274003. [PMID: 20571190 DOI: 10.1088/0957-4484/21/27/274003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Quantum point contacts are in use as an on-chip capacitative readout for the charge state of quantum dot systems. Here we investigate experimentally the back-action of quantum point contacts (QPCs) on a nearby double quantum dot (DQD). Driving current through a QPC influences the DQD state and leads to a measurable current flow in the DQD circuit with no bias voltage applied. The responsible mechanism is an indirect back-action process due to ohmic heating of the phonon bath. The system behaves like a thermoelectric engine, where a temperature gradient between the phonon bath and the electronic bath generates work observable as a measurable current flowing through the DQD.
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Affiliation(s)
- U Gasser
- Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland.
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32
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33
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Puller VI, Meir Y. How to measure the transmission phase through a quantum dot in a two-terminal interferometer. PHYSICAL REVIEW LETTERS 2010; 104:256801. [PMID: 20867406 DOI: 10.1103/physrevlett.104.256801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2010] [Indexed: 05/29/2023]
Abstract
Measurement of the transmission phase through a quantum dot (QD) embedded in an arm of a two-terminal Aharonov-Bohm (AB) interferometer is inhibited by phase symmetry, i.e., the property that the linear response conductance of a two-terminal device is an even function of the magnetic field. It is demonstrated that in a setup consisting of an interferometer with a QD in each of its arms, with one of the QDs capacitively coupled to a nearby quantum point contact (QPC), phase symmetry is broken when a finite voltage bias is applied to the QPC. The transmission phase via the uncoupled QD can then be deduced from the amplitude of the odd component of the AB oscillations.
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Affiliation(s)
- Vadim I Puller
- Department of Physics, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
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34
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Zakka-Bajjani E, Dufouleur J, Coulombel N, Roche P, Glattli DC, Portier F. Experimental determination of the statistics of photons emitted by a tunnel junction. PHYSICAL REVIEW LETTERS 2010; 104:206802. [PMID: 20867050 DOI: 10.1103/physrevlett.104.206802] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Indexed: 05/29/2023]
Abstract
We report on an Hanbury Brown-Twiss experiment probing the statistics of microwave photons emitted by a tunnel junction in the shot-noise regime at low temperature. By measuring the cross correlation of the fluctuations of the occupation numbers of the photon modes of both detection branches, we show that while the statistics of electrons is Poissonian, the photons obey chaotic statistics. This is observed even for low photon occupation number when the voltage across the junction is close to hν/e.
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Affiliation(s)
- Eva Zakka-Bajjani
- Service de Physique de l'Etat Condensé/IRAMIS/DSM (CNRS URA 2464), CEA Saclay, F-91191 Gif-sur-Yvette, France
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35
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Harbusch D, Taubert D, Tranitz HP, Wegscheider W, Ludwig S. Phonon-mediated versus coulombic backaction in quantum dot circuits. PHYSICAL REVIEW LETTERS 2010; 104:196801. [PMID: 20866986 DOI: 10.1103/physrevlett.104.196801] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2009] [Indexed: 05/29/2023]
Abstract
Quantum point contacts (QPCs) are commonly employed to detect capacitively the charge state of coupled quantum dots (QDs). An indirect backaction of a biased QPC onto a double QD laterally defined in a GaAs/AlGaAs heterostructure is observed. Energy is emitted by nonequilibrium charge carriers in the leads of the biased QPC. Part of this energy is absorbed by the double QD where it causes charge fluctuations that can be observed under certain conditions in its stability diagram. By investigating the spectrum of the absorbed energy, we find that both acoustic phonons and Coulomb interaction can be involved in the backaction, depending on the geometry and coupling constants.
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Affiliation(s)
- D Harbusch
- Center for NanoScience and Fakultät für Physik, Ludwig-Maximilians-Universität München, Geschwister-Scholl-Platz 1, D-80539 München, Germany
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36
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Young CE, Clerk AA. Inelastic backaction due to quantum point contact charge fluctuations. PHYSICAL REVIEW LETTERS 2010; 104:186803. [PMID: 20482197 DOI: 10.1103/physrevlett.104.186803] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2009] [Indexed: 05/29/2023]
Abstract
We study theoretically transitions of a double quantum-dot qubit caused by nonequilibrium charge fluctuations in a nearby quantum point contact (QPC) used as a detector. We show that these transitions are related to the fundamental Heisenberg backaction associated with the measurement, and use the uncertainty principle to derive a lower bound on the transition rates. We also derive simple expressions for the transition rates for the usual model of a QPC as a mesoscopic conductor, with screening treated at the RPA level. Finally, numerical results are presented which demonstrate that the charge noise and shot noise backaction mechanisms can be distinguished in QPCs having nonadiabatic potentials. The enhanced sensitivity of the charge noise to the QPC potential is explained in terms of interference contributions similar to those which cause Friedel oscillations.
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Affiliation(s)
- C E Young
- Department of Physics, McGill University, Montreal, Quebec, Canada H3A 2T8
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37
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Schinner GJ, Tranitz HP, Wegscheider W, Kotthaus JP, Ludwig S. Phonon-mediated nonequilibrium interaction between nanoscale devices. PHYSICAL REVIEW LETTERS 2009; 102:186801. [PMID: 19518896 DOI: 10.1103/physrevlett.102.186801] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2009] [Indexed: 05/27/2023]
Abstract
Interactions between mesoscopic devices induced by interface acoustic phonons propagating in the plane of a two-dimensional electron system (2DES) are investigated by phonon spectroscopy. In our experiments, ballistic electrons injected from a biased quantum point contact emit phonons and a portion of them are reabsorbed exciting electrons in a nearby degenerate 2DES. We perform energy spectroscopy on these excited electrons employing a tunable electrostatic barrier in an electrically separate and unbiased detector circuit. The transferred energy is found to be bounded by a maximum value corresponding to Fermi-level electrons excited and backscattered by absorbing interface phonons. Our results imply that phonon-mediated interaction plays an important role for the decoherence of solid-state-based quantum circuits.
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Affiliation(s)
- G J Schinner
- Center for NanoScience and Fakultät für Physik, Ludwig-Maximilians-Universität, Geschwister-Scholl-Platz 1, 80539 München, Germany
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38
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Gustavsson S, Leturcq R, Studer M, Ihn T, Ensslin K, Driscoll DC, Gossard AC. Time-resolved detection of single-electron interference. NANO LETTERS 2008; 8:2547-2550. [PMID: 18611057 DOI: 10.1021/nl801689t] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We demonstrate real-time detection of self-interfering electrons in a double quantum dot embedded in an Aharonov-Bohm interferometer, with visibility approaching unity. We use a quantum point contact as a charge detector to perform time-resolved measurements of single-electron tunneling. With increased bias voltage, the quantum point contact exerts a back-action on the interferometer leading to decoherence. We attribute this to emission of radiation from the quantum point contact, which drives noncoherent electronic transitions in the quantum dots.
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Affiliation(s)
- S Gustavsson
- Solid State Physics Laboratory, ETH Zürich, Zürich, Switzerland.
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39
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Taubert D, Pioro-Ladrière M, Schröer D, Harbusch D, Sachrajda AS, Ludwig S. Telegraph noise in coupled quantum dot circuits induced by a quantum point contact. PHYSICAL REVIEW LETTERS 2008; 100:176805. [PMID: 18518321 DOI: 10.1103/physrevlett.100.176805] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2008] [Indexed: 05/26/2023]
Abstract
Charge detection utilizing a highly biased quantum point contact has become the most effective probe for studying few electron quantum dot circuits. Measurements on double and triple quantum dot circuits is performed to clarify a back action role of charge sensing on the confined electrons. The quantum point contact triggers inelastic transitions, which occur quite generally. Under specific device and measurement conditions these transitions manifest themselves as bounded regimes of telegraph noise within a stability diagram. A nonequilibrium transition from artificial atomic to molecular behavior is identified. Consequences for quantum information applications are discussed.
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Affiliation(s)
- D Taubert
- Center for NanoScience and Fakultät für Physik, Ludwig-Maximilians-Universität, Geschwister-Scholl-Platz 1, D-80539 München, Germany
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40
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Zakka-Bajjani E, Ségala J, Portier F, Roche P, Glattli DC, Cavanna A, Jin Y. Experimental test of the high-frequency quantum shot noise theory in a quantum point contact. PHYSICAL REVIEW LETTERS 2007; 99:236803. [PMID: 18233393 DOI: 10.1103/physrevlett.99.236803] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2007] [Indexed: 05/25/2023]
Abstract
We report on direct measurements of the electronic shot noise of a quantum point contact at frequencies nu in the range 4-8 GHz. The very small energy scale used ensures energy independent transmissions of the few transmitted electronic modes and their accurate knowledge. Both the thermal energy and the quantum point contact drain-source voltage V_{ds} are comparable to the photon energy hnu leading to observation of the shot noise suppression when V_{ds}<hnu/e. Our measurements provide the first complete test of the finite frequency shot noise scattering theory without adjustable parameters.
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Affiliation(s)
- E Zakka-Bajjani
- Nanoelectronic Group, Service de Physique de l'Etat Condensé, CEA Saclay, F-91191 Gif-Sur-Yvette, France
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