| 51. |
- Shekhter, Robert I., 1947, et al.
(författare)
-
Electronic spin working mechanically (Review Article)
- 2014
-
Ingår i: Low temperature physics. - : AIP Publishing. - 1063-777X .- 1090-6517. ; 40:7, s. 600-614
-
Tidskriftsartikel (refereegranskat)abstract
- A single-electron tunneling (SET) device with a nanoscale central island that can move with respect to the bulk source- and drain electrodes allows for a nanoelectromechanical (NEM) coupling between the electrical current through the device and mechanical vibrations of the island. Although an electromechanical “shuttle” instability and the associated phenomenon of single-electron shuttling were predicted more than 15 years ago, both theoretical and experimental studies of NEM-SET structures are still carried out. New functionalities based on quantum coherence, Coulomb correlations and coherent electron-spin dynamics are of particular current interest. In this article we present a short review of recent activities in this area.
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| 52. |
- Shekhter, Robert I., 1947, et al.
(författare)
-
Mechano-electronic and electro-mechanical energy transfer in mesoscopic superconducting weak links
- 2012
-
Ingår i: Comptes Rendus Physique. - : Elsevier BV. - 1878-1535 .- 1631-0705. ; 13:5, s. 426-439
-
Forskningsöversikt (refereegranskat)abstract
- In this review we discuss how the nano-electro-mechanical properties of a superconducting weak link, formed by a suspended nanowire bridging two superconductors, can strongly affect mesoscopic effects in both the electronic and the mechanical subsystem. In particular we will discuss how quantum coherence and electron–electron (Coulomb) correlations may result in the possibility to resonantly redistribute energy between the electronic and mechanical degrees of freedom, allowing controllable switching between pumping and cooling of the nano-mechanical vibrations of the suspended nanowire. The two regimes of a given current and a given voltage supplied to the nano-electro-mechanical weak link is considered, resulting respectively in the possibility of ground-state cooling or resonant generation of nano-mechanical vibrations for realistic experimental parameters.
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| 53. |
- Shekhter, Robert I., 1947, et al.
(författare)
-
Nanoelectromechanics of shuttle devices
- 2013
-
Ingår i: Nanoelectromechanical Systems. - : Portico. - 2299-3169. ; 1, s. 1-25
-
Tidskriftsartikel (refereegranskat)abstract
- A single-electron tunneling (SET) device with a nanoscale central island that can move with respect to the bulk sourceand drain electrodes allows for a nanoelectromechanical (NEM) coupling between the electrical current through the device and the mechanical vibrations of the island. Although the electromechanical “shuttle” instability and the associated phenomenon of single-electron shuttling were predicted more than 15 years ago, both theoretical and experimental studies of NEM-SET structures are still carried out. New functionalities based on quantum coherence, Coulomb correlations and coherent electron-spin dynamics are still of particular interest. In this article we present a short review of recent activities in this area.
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| 54. |
- Shekhter, Robert I., 1947, et al.
(författare)
-
Nanomechanical shuttle transfer of electrons
- 2007
-
Ingår i: Journal of Computational and Theoretical Nanoscience. ; 4, s. 860-895
-
Tidskriftsartikel (refereegranskat)abstract
- Small metal particles embedded in a material subject to an external electric field can contribute to the conductance by mechanically transporting charge. This was already demonstrated in Millikan's pioneering experiment that proved that charge is quantized. While the effect of charge quantization can be pronounced for submicron conducting particles and lead to Coulomb blockade of W tunnelling, the nanomechanical aspect of single-electron tunnelling becomes prominent only in 5 nanometer-size self-assembled structures. The coupling between mechanical deformations and LU electronic charge transport in composite materials with nanoscale components gives rise to a new class of phenomena-nanoelectromechanical transport-and opens up a new route in nanotechnology. The interplay between the electronic and mechanical degrees of freedom is especially important in nanocomposites consisting of materials with very different elastic properties. A typical system of this kind is a single-electron transistor (SET) with cleformable tunnel barriers, a so called Nano-Electro-Mechanic.al SET (NEM-SET). The new kind of electron transport in this and other types of nanodevices is referred to as "shuttle transport" of electrons, which implies that electrons is transferred between metallic leads via a movable small-sized cluster. The present review is devoted to the fundamental aspects of shuttle transport and to a description of major developments in the theoretical and experimental research in the field. Prospective applications of this exciting phenomenon that remarkably combines traditional mechanics of materials with the most advanced effects of quantum physics, will also be touched upon.
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| 55. |
- Shekhter, Robert I., 1947, et al.
(författare)
-
Nonequilibrium and quantum coherent phenomena in the electromechanics of suspended nanowires
- 2009
-
Ingår i: Low Temperature Physics. - : AIP Publishing. - 1090-6517 .- 1063-777X. ; 35:8
-
Forskningsöversikt (refereegranskat)abstract
- Strong coupling between electronic and mechanical degrees of freedom is a basic requirement for the operation of any nanoelectromechanical device. In this Review we consider such devices and in particular investigate the properties of small tunnel-junction nanostructures that contain a movable element in the form of a suspended nanowire. In these systems, electrical currents and charge can be concentrated to small spatial volumes resulting in strong coupling between the mechanics and the charge transport. As a result, a variety of mesoscopic phenomena appear, which can be used for the transduction of electrical currents into mechanical operation. Here we will in particular consider nanoelectromechanical dynamics far from equilibrium and the effect of quantum coherence in both the electronic and mechanical degrees of freedom in the context of both normal and superconducting nanostructures.
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| 56. |
- Shekhter, Robert I., 1947, et al.
(författare)
-
Shuttle transport in nanostructures
- 2006
-
Ingår i: Handbook of theoretical and computational nanotechnology. - : American Scientific Publishers. - 1588830470
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The coupling between mechanical deformations and electronic charge transport in nanostructures and in composite materials with nanoscale components gives rise to a new class of phenomena | nanoelectromechanical transport | and opens up a new route in nanotechnology. The interplay between the electronic and mechanical degrees of freedom is especially important in nanocomposites consisting of materials with very di®erent elastic properties. Mechanical degrees of freedom take on a primary role in the charge transfer process in many single-electron devices, where transport is controlled by quantum-mechanical tunnelling and Coulomb interactions, but where tunnel barriers can be modi¯ed as a result of mechanical motion. A typical system of this kind is a single-electron transistor (SET) with deformable tunnel barriers, a so called Nano-Electro-Mechanical SET (NEM- SET). The new kind of electron transport in this and other types of nanodevices is referred to as "shuttle transport" of electrons, which implies that electrons is transferred between metallic leads via a movable small-sized cluster. The present review is devoted to the fundamental aspects of shuttle transport and to a description of major developments in the theoretical and experimental research in the ¯eld. Prospective applications of this exciting phenomenon that remarkably combines traditional mechanics of materials with the most advanced e®ects of quantum physics, will also be touched upon.
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| 57. |
- Song, T., et al.
(författare)
-
Self-sustained oscillations in nanoelectromechanical systems induced by Kondo resonance
- 2014
-
Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 16
-
Tidskriftsartikel (refereegranskat)abstract
- We investigate the instability and dynamical properties of nanoelectromechanical systems represented by a single-electron device containing movable quantum dots attached to a vibrating cantilever via asymmetric tunnel contacts. The Kondo resonance in electron tunneling between the source and shuttle facilitates self-sustained oscillations originating from the strong coupling of mechanical and electronic/spin degrees of freedom. We analyze a stability diagram for the two-channel Kondo shuttling regime due to limitations given by the electromotive force acting on a moving shuttle, and find that the saturation oscillation amplitude is associated with the retardation effect of the Kondo cloud. The results shed light on possible ways to experimentally realize the Kondo-cloud dynamical probe by using high mechanical dissipation tunability as well as supersensitive detection of mechanical displacement.
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| 58. |
- Song, T., et al.
(författare)
-
Shuttle-promoted nano-mechanical current switch
- 2015
-
Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 107:12
-
Tidskriftsartikel (refereegranskat)abstract
- We investigate electron shuttling in three-terminal nanoelectromechanical device built on a movable metallic rod oscillating between two drains. The device shows a double-well shaped electromechanical potential tunable by a source-drain bias voltage. Four stationary regimes controllable by the bias are found for this device: (i) single stable fixed point, (ii) two stable fixed points, (iii) two limit cycles, and (iv) single limit cycle. In the presence of perpendicular magnetic field, the Lorentz force makes possible switching from one electromechanical state to another. The mechanism of tunable transitions between various stable regimes based on the interplay between voltage controlled electromechanical instability and magnetically controlled switching is suggested. The switching phenomenon is implemented for achieving both a reliable active current switch and sensoring of small variations of magnetic field.
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| 59. |
- Sonne, Gustav, 1982, et al.
(författare)
-
Cooling of a suspended nanowire by an ac Josephson current flow
- 2010
-
Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 104:22
-
Tidskriftsartikel (refereegranskat)abstract
- We consider a nanoelectromechanical Josephson junction, where a suspended nanowire serves as a superconducting weak link, and show that an applied dc bias voltage can result in suppression of the flexural vibrations of the wire. This cooling effect is achieved through the transfer of vibronic energy quanta first to voltage-driven Andreev states and then to extended quasiparticle electronic states. Our analysis, which is performed for a nanowire in the form of a metallic carbon nanotube and in the framework of the density matrix formalism, shows that such self-cooling is possible down to the ground state of the flexural vibration mode of the nanowire.
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| 60. |
- Sonne, Gustav, 1982, et al.
(författare)
-
Ground-State Cooling of a Suspended Nanowire through Inelastic Macroscopic Quantum Tunneling in a Current-Biased Josephson Junction
- 2011
-
Ingår i: Physical Reveiw Letters. - 0031-9007 .- 1079-7114. ; 106:16
-
Tidskriftsartikel (refereegranskat)abstract
- We demonstrate that a suspended nanowire forming a weak link between two superconductors can be cooled to its motional ground state by a supercurrent flow. The predicted cooling mechanism has its origins in magnetic field induced inelastic tunneling of the macroscopic superconducting phase associated with the junction. Furthermore, we show that the voltage drop over the junction is proportional to the average population of the vibrational modes in the stationary regime, a phenomenon which can be used to probe the level of cooling.
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| 61. |
- Sonne, Gustav, 1982, et al.
(författare)
-
High-temperature excess current and quantum suppression of electronic backscattering
- 2008
-
Ingår i: Europhysics Letters. - : IOP Publishing. - 0295-5075 .- 1286-4854. ; 84
-
Tidskriftsartikel (refereegranskat)abstract
- We consider the electronic current through a one-dimensional conductor in the ballistic transport regime and show that the quantum oscillations of a weakly pinned single-scattering target results in a temperature- and bias-voltage independent excess current at large bias voltages. This is a genuine quantum effect on transport that derives from an exponential reduction of electron backscattering in the elastic channel due to quantum delocalisation of the scatterer and from a suppression of low-energy electron backscattering in the inelastic channels caused by the Pauli exclusion principle. We show that both the mass of the target and the frequency of its quantum vibrations can be measured by studying the differential conductance and the excess current. We apply our analysis to the particular case of a weakly pinned C60 molecule encapsulated by a single-wall carbon nanotube and find that the discussed phenomena are experimentally observable.
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| 62. |
- Sonne, Gustav, 1982, et al.
(författare)
-
Superconducting pumping of nanomechanical vibrations
- 2008
-
Ingår i: Physical Review B. - 1098-0121. ; 78, s. 144501-
-
Tidskriftsartikel (refereegranskat)abstract
- We demonstrate that a supercurrent can pump energy from a battery that provides a voltage bias into nanomechanical vibrations. Using a device containing a nanowire Josephson weak link as an example we show that a nonlinear coupling between the supercurrent and a static external magnetic field leads to a Lorentz force that excites bending vibrations of the wire at resonance conditions. We also demonstrate the possibility to achieve more than one regime of stationary nonlinear vibrations and how to detect them via the associated dc Josephson currents and we discuss possible applications of such a multistable nanoelectromechanical dynamics.
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| 63. |
- Sonne, Gustav, 1982, et al.
(författare)
-
Voltage-driven superconducting weak link as a refrigerator for cooling of nanomechanical vibrations
- 2010
-
Ingår i: Low Temperature Physics. - : AIP Publishing. - 1090-6517 .- 1063-777X. ; 36:10
-
Tidskriftsartikel (refereegranskat)abstract
- We consider a new type of cooling mechanism for a suspended nanowire acting as a weak link between two superconductive electrodes. By applying a bias voltage over the system, we show that the system can be viewed as a refrigerator for the nanomechanical vibrations, where energy is continuously transferred from the vibrational degrees of freedom to the extended quasiparticle states in the leads through the periodic modulation of the inter-Andreev level separation. The necessary coupling between the electronic and mechanical degrees of freedom responsible for this energy-transfer can be achieved both with an external magnetic or electrical field, and is shown to lead to an effective cooling of the vibrating nanowire. Using realistic parameters for a suspended nanowire in the form of a metallic carbon nanotube we analyze the evolution of the density matrix and demonstrate the possibility to cool the system down to a stationary vibron population of ~0.1. Furthermore, it is shown that the stationary occupancy of the vibrational modes of the nanowire can be directly probed from the dc current responsible for carrying away the absorbed energy from the vibrating nanowire.
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| 64. |
- Vikström, Anton, 1986, et al.
(författare)
-
Hypersonic edge solitons in graphene under quantum Hall effect
- 2015
-
Ingår i: Europhysics Letters. - : IOP Publishing. - 0295-5075 .- 1286-4854. ; 112:4, s. 44004-
-
Tidskriftsartikel (refereegranskat)abstract
- We consider a graphene sheet with a zigzag edge subject to a perpendicular magnetic field and investigate the evolution of in-plane elastic edge deformation. In such a system, resonant electronic edge states generate a strong Landau damping of low-amplitude acoustic edge waves with specific wave vectors. We study the propagation of a short hypersonic edge pulse in the case of a strong interaction with resonant electronic edge states. Using the resonance approximation, we derive the system of equations describing the evolution of the pulse and show that self-induced transparency can appear under certain conditions. As a consequence, pulses with particular profiles can travel without attenuation at a velocity different from that of sound.
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| 65. |
- Vikström, Anton, 1986, et al.
(författare)
-
Nanoelectromechanical Heat Engine Based on Electron-Electron Interaction
- 2016
-
Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 117:24
-
Tidskriftsartikel (refereegranskat)abstract
- We theoretically show that a nanoelectromechanical system can be mechanically actuated by a heat flow through it via an electron-electron interaction. In contrast to most known actuation mechanisms in similar systems, this new mechanism does not involve an electronic current nor external ac fields. Instead, the mechanism relies on deflection-dependent tunneling rates and a heat flow which is mediated by an electron-electron interaction while an electronic current through the device is prohibited by, for instance, a spin-valve effect. Therefore, the system resembles a nanoelectromechanical heat engine. We derive a criterion for the mechanical instability and estimate the amplitude of the resulting self-sustained oscillations. Estimations show that the suggested phenomenon can be studied using available experimental techniques.
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| 66. |
- Voinova, Marina, 1958, et al.
(författare)
-
Physical processes in polymeric filters used for dialysis
- 2019
-
Ingår i: Polymers. - : MDPI AG. - 2073-4360. ; 11:3
-
Forskningsöversikt (refereegranskat)abstract
- The key physical processes in polymeric filters used for the blood purification include transport across the capillary wall and the interaction of blood cells with the polymer membrane surface. Theoretical modeling of membrane transport is an important tool which provides researchers with a quantification of the complex phenomena involved in dialysis. In the paper, we present a dense review of the most successful theoretical approaches to the description of transport across the polymeric membrane wall as well as the cell-polymer surface interaction, and refer to the corresponding experimental methods while studying these phenomena in dialyzing filters.
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| 67. |
- Vyurkov, V., et al.
(författare)
-
Quantum computing based on space states without charge transfer
- 2010
-
Ingår i: Physics Letters, Section A: General, Atomic and Solid State Physics. - : Elsevier BV. - 0375-9601. ; 374:33, s. 3285-3291
-
Tidskriftsartikel (refereegranskat)abstract
- An implementation of a quantum computer based on space states in double quantum dots is discussed. There is no charge transfer in qubits during a calculation, therefore, uncontrolled entanglement between qubits due to long-range Coulomb interaction is suppressed. Encoding and processing of quantum information is merely performed on symmetric and antisymmetric states of the electron in double quantum dots. Other plausible sources of decoherence caused by interaction with phonons and gates could be substantially suppressed in the structure as well. We also demonstrate how all necessary quantum logic operations, initialization, writing, and read-out could be carried out in the computer. (C) 2010 Elsevier B.V. All rights reserved.
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