Pair tunneling and shot noise through a single molecule in a strong electron-phonon coupling regime

Hwang, Myung-Joong; Choi, Myeon-Song; López, Rosa

doi:10.1103/physrevb.76.165312

Cited by 17 publications

(23 citation statements)

References 35 publications

(48 reference statements)

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“…For sufficiently strong Holstein coupling, the induced polaronic shift can overcome the Coulomb repulsion, resulting in a bipolaronic attraction between electrons and thus a negative effective charging energy for the QD. This possibility has spurred some theories exploring the manifestation of negative charging energy in transport, which mainly concern the charge Kondo effect [8], pair tunneling [9][10][11], and cotunneling [10]. However, these high-order transport behaviors are fragile, requiring harsh experimental conditions.…”

Section: Introductionmentioning

confidence: 99%

Bipolaronic blockade effect in quantum dots with negative charging energy

Fang¹,

Zhang²,

Niu³

et al. 2014

EPL

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We investigate single-electron transport through quantum dots with negative charging energy induced by a polaronic energy shift. For weak dot-lead tunnel couplings, we demonstrate a bipolaronic blockade effect at low biases which suppresses the oscillating linear conductance, while the conductance resonances under large biases are enhanced. Novel conductance plateau develops when the coupling asymmetry is introduced, with its height and width tuned by the coupling strength and external magnetic field. It is further shown that the amplitude ratio of magnetic-split conductance peaks changes from 3 to 1 for increasing coupling asymmetry. Though we demonstrate all these transport phenomena in the low-order single-electron tunneling regime, they are already strikingly different from the usual Coulomb blockade physics and are easy to observe experimentally.

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Section: Introductionmentioning

confidence: 99%

Bipolaronic blockade effect in quantum dots with negative charging energy

Fang¹,

Zhang²,

Niu³

et al. 2014

EPL

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“…This effect is known as the Franck-Condon blockade [12,15,[29][30][31], and arises for the following reason. In a transport situation, the system is voltage-tuned to a point along one of the instability lines, e.g., the 0/2 boundary.…”

Section: Resultsmentioning

confidence: 99%

“…The possibility of vibration-mediated attractive interaction among confined electrons has been discussed, e.g., in the context of amorphous semiconductors [8], vacancies in silicon [9,10], fullerenes [11], and molecular junctions [12][13][14][15]. Figure 1a depicts the simplest model capturing the basic ingredients of the effect: it involves (i) a single vibrational mode (phonon), characterized by a mass m and frequency ω, (ii) a single electronic orbital that can be occupied by one or two electrons, i.e., the occupation number is N ∈ {0, 1, 2}; this orbital is characterized by an on-site energy and a repulsive Coulomb energy U > 0, (iii) the coupling between the phonon and the confined charge, characterized by the force λ encoding the coupling strength, and (iv) a (zero-temperature) electron reservoir, with Fermi energy * Corresponding author: matthias.droth@mail.bme.hu µ = 0, which can supply electrons to the orbital.…”

Section: Introductionmentioning

confidence: 99%

“…Figure 1a depicts the simplest model capturing the basic ingredients of the effect: it involves (i) a single vibrational mode (phonon), characterized by a mass m and frequency ω, (ii) a single electronic orbital that can be occupied by one or two electrons, i.e., the occupation number is N ∈ {0, 1, 2}; this orbital is characterized by an on-site energy and a repulsive Coulomb energy U > 0, (iii) the coupling between the phonon and the confined charge, characterized by the force λ encoding the coupling strength, and (iv) a (zero-temperature) electron reservoir, with Fermi energy * Corresponding author: matthias.droth@mail.bme.hu µ = 0, which can supply electrons to the orbital. We refer to this as the Anderson-Holstein model [15]. (See Methods for more details.)…”

Section: Introductionmentioning

confidence: 99%

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Electron-electron attraction in an engineered electromechanical system

2017

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Two electrons in a quantum dot repel each other: their interaction can be characterized by a positive interaction energy. From the theory of superconductivity, we also know that mechanical vibrations of the crystal lattice can make the electron-electron interaction attractive. Analogously, if a quantum dot interacts with a mechanical degree of freedom, the effective interaction energy can be negative; that is, the electron-electron interaction might be attractive. In this work, we propose and theoretically study an engineered electromechanical system that exhibits electron-electron attraction: a quantum dot suspended on a nonlinear mechanical resonator, tuned by a bottom and a top gate electrode. We focus on the example of a dot embedded in a suspended graphene ribbon, for which we identify conditions for electron-electron attraction. Our results suggest the possibility of electronic transport via tunneling of packets of multiple electrons in such devices, similar to that in superconducting nanostructures, but without the use of any superconducting elements.

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“…Pair-tunneling.-Single-particle transitions between the reservoir and the wire are excluded for sufficiently low values of temperature and bias Á when U < 0. Two-particle transitions may occur due to higher-order processes in the coupling between the reservoirs and the wire [31,32]: Normal cotunneling results in a weak background conductance for any bias. Pair-tunneling, neglecting the effects of temperature and lifetime broadening, is only allowed for jE 2nþ2 À E 2n j < Á, where E N is the ground state energy of the N-particle state and n is an integer.…”

Section: Fig 2 (Color Onlinementioning

confidence: 99%

Total Current Blockade in an Ultracold Dipolar Quantum Wire

et al. 2013

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Total current blockade in an ultracold dipolar quantum wire.Kristinsdottir, Liney Halla; Karlström, Olov; Bjerlin, Johannes; Cremon, Jonas; Schlagheck, P; Wacker, Andreas; Reimann, Stephanie General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal Take down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Cold-atom systems offer a great potential for the future design of new mesoscopic quantum systems with properties that are fundamentally different from semiconductor nanostructures. Here, we investigate the quantum-gas analogue of a quantum wire and find a new scenario for the quantum transport: Attractive interactions may lead to a complete suppression of current in the low-bias range, a total current blockade. We demonstrate this effect for the example of ultracold quantum gases with dipolar interactions.

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Pair tunneling and shot noise through a single molecule in a strong electron-phonon coupling regime

Cited by 17 publications

References 35 publications

Bipolaronic blockade effect in quantum dots with negative charging energy

Bipolaronic blockade effect in quantum dots with negative charging energy

Electron-electron attraction in an engineered electromechanical system

Total Current Blockade in an Ultracold Dipolar Quantum Wire

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