| 1. |
- Eriksson, Martin, 1989, et al.
(författare)
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Nonresonant high frequency excitation of mechanical vibrations in a graphene based nanoresonator
- 2015
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Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 17
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Tidskriftsartikel (refereegranskat)abstract
- We theoretically analyze the dynamics of a suspended graphene membrane which is in tunnel contact with grounded metallic electrodes and subjected to ac-electrostatic potential induced by a gate electrode. It is shown that for such a system the retardation effects in the electronic subsystem generate an effective pumping for the relatively slow mechanical vibrations if the driving frequency exceeds the inverse charge relaxation time. Under this condition there is a critical value of the driving voltage amplitude above which the pumping overcomes the intrinsic damping of the mechanical resonator, leading to a mechanical instability. This nonresonant instability is saturated by nonlinear damping and the system exhibits self-sustained oscillations of relatively large amplitude.
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| 2. |
- Eriksson, Martin, 1989, et al.
(författare)
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Selective nonresonant excitation of vibrational modes in suspended graphene via vibron-plasmon interaction
- 2015
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Ingår i: 2D Materials. - : IOP Publishing. - 2053-1583. ; 2:4
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Tidskriftsartikel (refereegranskat)abstract
- We theoretically study a doped graphene ribbon suspended over a trench and subject to an ac-electrical field polarized perpendicularly to the graphene plane. In such a system, the external ac-field is coupled to the relatively slow mechanical vibrations via plasmonic oscillations in the isolated graphene sheet. We show that the electrical field generates an effective pumping of the mechanical modes. It is demonstrated that in the case of underdamped plasma oscillation, a peculiar kind of geometrical resonance of the mechanical and plasma oscillations appear. The efficiency of pumping significantly increases when the wavenumber of the mechanical mode is in close agreement with the wavenumber of the plasma waves. The intensity of the pumping increases with the wavenumber of the mode. This phenomenon allows selective actuation of different mechanical modes, although the driving field is homogeneous.
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| 3. |
- Kulinich, S.I., et al.
(författare)
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Cooling of mechanical vibrations by heat flow
- 2018
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Ingår i: Low Temperature Physics. - : AIP Publishing. - 1063-777X .- 1090-6517. ; 44:12, s. 1232-1232
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Tidskriftsartikel (refereegranskat)abstract
- We theoretically consider a nanomechanical link between two metallic leads subject to a temperature drop. It is shown that mechanical dynamics of such system can be strongly affected by a heat flow through it via the position dependent electron-electron interaction, even though the electronic transport between leads is blocked. In particular, it is demonstrated that, under certain conditions, the stationary distribution of the excitations in the mechanical subsystem has a Boltzmann form with an effective temperature, which is much lower than the temperature of the environment; this seems rather counterintuitive. We also find that a change in the direction of the temperature gradient can result in the generation of mechanical vibrations rather than the heating of the mechanical subsystem.
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| 4. |
- Parafilo, A. V., et al.
(författare)
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Kondo effect in a Aharonov-Casher interferometer
- 2019
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Ingår i: Physical Review B. - 2469-9950 .- 2469-9969. ; 100:23
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Tidskriftsartikel (refereegranskat)abstract
- We consider a model describing a spin field-effect transistor based on a quantum nanowire with a tunable spin-orbit interaction embedded between two ferromagnetic leads with anticollinear magnetization. We investigate a regime of a strong interplay between resonance Kondo scattering and interference associated with the Aharonov-Casher effect. Using the Keldysh technique at a weak-coupling regime we calculate perturbatively the charge current. It is predicted that the effects of the spin-orbit interaction result in a nonvanishing current for any spin polarization of the leads including the case of fully polarized anticollinear contacts. We analyze the influence of the Aharonov-Casher phase and degree of spin polarization in the leads onto a Kondo temperature.
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| 5. |
- Parafilo, A. V., et al.
(författare)
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Spin-mediated Photomechanical Coupling of a Nanoelectromechanical Shuttle
- 2016
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 117:5
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Tidskriftsartikel (refereegranskat)abstract
- We show that nanomechanical vibrations in a magnetic shuttle device can be strongly affected by external microwave irradiation through photo-assisted electronic spin-flip transitions. Mechanical consequences of these spin flips are due to a spin-dependent magnetic force, which may lead to a nanomechanical instability in the device. We derive a criterion for the instability to occur and analyze different regimes of nanomechanical oscillations. Possible experimental realizations of the spin-mediated photomechanical instability and detection of the device backaction are discussed.
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| 6. |
- Song, T., et al.
(författare)
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Shuttle-promoted nano-mechanical current switch
- 2015
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 107:12
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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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| 7. |
- Vikström, Anton, 1986, et al.
(författare)
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Hypersonic edge solitons in graphene under quantum Hall effect
- 2015
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Ingår i: Europhysics Letters. - : IOP Publishing. - 0295-5075 .- 1286-4854. ; 112:4, s. 44004-
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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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| 8. |
- Vikström, Anton, 1986, et al.
(författare)
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Nanoelectromechanical Heat Engine Based on Electron-Electron Interaction
- 2016
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Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 117:24
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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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| 9. |
- Voinova, Marina, 1958, et al.
(författare)
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Physical processes in polymeric filters used for dialysis
- 2019
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Ingår i: Polymers. - : MDPI AG. - 2073-4360. ; 11:3
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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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