| 1. |
- Parafilo, A. V., et al.
(författare)
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Thermoelectric effects in electron chiral tunneling in metallic carbon nanotubes
- 2015
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Ingår i: Superlattices and Microstructures. - : Elsevier BV. - 0749-6036. ; 88, s. 72-79
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Tidskriftsartikel (refereegranskat)abstract
- Thermoelectric effects in a metallic single-wall carbon nanotube in the presence of long-range electrostatic and pseudomagnetic potentials (produced by strain) are considered. It is shown that for strong scattering potentials (chiral tunneling) a pronounced energy "gap" appears in the energy dependence of electron transmission coefficient. This results in strong violation of Wiedemann-Franz law and in a peak-like behavior of thermopower as a function of chemical potential. The electronic figure-of-merit (ZT) is calculated and shown to be sensitive at low temperatures to nanotube chirality. By tuning chemical potential, ZT can reach high values (ZT approximate to 5) that makes specially engineered nanotube-based thermocouple to be a promising nano-device with a high thermoelectric performance. (C) 2015 Elsevier Ltd. All rights reserved.
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| 2. |
- Shkop, A. D., et al.
(författare)
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Low-energy anomalies in electron tunneling through strongly asymmetric Majorana nanowire
- 2016
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Ingår i: Low Temperature Physics. - : AIP Publishing. - 1063-777X .- 1090-6517. ; 42:4, s. 308-312
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Tidskriftsartikel (refereegranskat)abstract
- Electron transport through Majorana nanowire with strongly asymmetric couplings to normal metal leads is considered. In three terminal geometry (electrically grounded nanowire) it is shown that the presence of unbiased electrode restores zero-bias anomaly even for strong Majorana energy splitting. For effectively two-terminal geometry we show that electrical current through asymmetric Majorana junction is qualitatively different from the analogous current through a resonant (Breit-Wigner) level. Published by AIP Publishing.
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| 3. |
- Kulinich, Sergeij I., et al.
(författare)
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Nanomechanics of a magnetic shuttle device
- 2014
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Ingår i: Low temperature physics. - : AIP Publishing. - 1063-777X .- 1090-6517. ; 40:10, s. 1161-1169
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Tidskriftsartikel (refereegranskat)abstract
- We show that self sustained mechanical vibrations in a model magnetic shuttle device can be driven by both the charge and the spin accumulated on the movable central island of the device. Different scenarios for how spin- and charge-induced shuttle instabilities may develop are discussed and shown to depend on whether there is a Coulomb blockade of tunneling or not. The crucial role of electronic spin flips in a magnetically driven shuttle is established and shown to cause giant magnetoresistance and dynamic magnetostriction effects.
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| 4. |
- Parafilo, A., et al.
(författare)
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Nanoelectromechanics of superconducting weak links
- 2012
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Ingår i: Low Temperature Physics. - : AIP Publishing. - 1063-777X .- 1090-6517. ; 38:4, s. 273-282
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Tidskriftsartikel (refereegranskat)abstract
- Nanoelectromechanical effects in superconducting weak links are considered. Three different superconducting devices are studied: (i) a single-Cooper-pair transistor, (ii) a transparent SNS junction, and (iii) a single-level quantum dot coupled to superconducting electrodes. The electromechanical coupling is due to electrostatic or magnetomotive forces acting on a movable part of the device. It is demonstrated that depending on the frequency of mechanical vibrations the electromechanical coupling could either suppress or enhance the Josephson current. Nonequilibrium effects associated with cooling of the vibrational subsystem or pumping energy into it at low bias voltages are discussed.
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| 5. |
- Parafilo, A. V., et al.
(författare)
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Chiral effects in normal and superconducting carbon nanotube-based nanostructures
- 2010
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Ingår i: Low Temperature Physics. - : AIP Publishing. - 1063-777X .- 1090-6517. ; 36:10/11, s. 959-968
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Tidskriftsartikel (refereegranskat)abstract
- The novel phenomenon of chiral tunneling in metallic single-wall carbon nanotubes is considered. It is induced by the interplay of electrostatic and pseudomagnetic effects in electron scattering in chiral nanotubes and is characterized by an oscillatory dependence of the electron transmission probability on the nanotube chiral angle and the strength of the scattering potential. The appearance of a special (Aharonov–Bohm-like) phase in chiral tunneling affects various phase-coherent phenomena in nanostructures. We examine chiral effects in: (i) persistent currents in circular nanotubes, (ii) Josephson currents in nanotube-based SNS junctions, and (iii) resonant electron tunneling through chiral nanotube-based quantum dots.
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| 6. |
- Parafilo, A. V., et al.
(författare)
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Chiral tunnelling in metallic carbon nanotubes
- 2011
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Ingår i: Physical Review B. - 1098-0121. ; 83
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Tidskriftsartikel (refereegranskat)abstract
- The concept of chiral tunneling in metallic single-wall carbon nanotubes, originating from the interplay of local electrostatic and pseudomagnetic potentials, is considered and applied to an evaluation of the Josephson current in a nanotube-based superconductor–normal metal–superconductor (SNS) junction and the persistent current in a circular nanotube. In the former case, an oscillatory dependence of the critical supercurrent on the potential strength and the nanotube chiral angle is predicted. In the latter case, the existence of a spontaneous persistent current in an isolated ringlike nanotube is discussed.
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| 7. |
- 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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| 8. |
- Parafilo, A. V., et al.
(författare)
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Manifestation of polaronic effects in Josephson currents
- 2013
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Ingår i: Low temperature physics. - : AIP Publishing. - 1063-777X .- 1090-6517. ; 39:8, s. 685-694
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Tidskriftsartikel (refereegranskat)abstract
- Polaronic effects on the Josephson current through a vibrating quantum dot are considered. In the regime of strong electron-vibron interactions they lead to a power-law suppression of the critical current. This is manifested in an anomalous temperature dependence of the critical current at temperatures of the order of the polaronic energy shift.
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| 9. |
- Parafilo, A. V., et al.
(författare)
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Nanomechanics driven by Andreev tunneling
- 2020
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Ingår i: Physical Review B. - 2469-9950 .- 2469-9969. ; 102:23
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Tidskriftsartikel (refereegranskat)abstract
- We predict and analyze mechanical instability and corresponding self-sustained mechanical oscillations occurring in a nanoelectromechanical system composed of a metallic carbon nanotube (CNT) suspended between two superconducting leads and coupled to a scanning tunneling microscope (STM) tip. We show that such phenomena are realized in the presence of both the coherent Andreev tunneling between the CNT and superconducting leads, and an incoherent single electron tunneling between the voltage biased STM tip and CNT. Treating the CNT as a single-level quantum dot, we demonstrate that the mechanical instability is controlled by the Josephson phase difference, relative position of the electron energy level, and the direction of the charge flow. It is found numerically that the emergence of the self-sustained oscillations leads to a substantial suppression of DC electric current. © 2020 American Physical Society.
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| 10. |
- Parafilo, A. V., et al.
(författare)
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Polaronic effects and thermally enhanced weak superconductivity
- 2014
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121. ; 89:11
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Tidskriftsartikel (refereegranskat)abstract
- We theoretically analyze the d.c Josephson current between two superconductors connected by a vibrating weak link. Assuming the weak link to be a ``quantum dot" we predict that the critical current is thermally enhanced at low temperatures if the electron-vibron interaction is strong and has an anomalous temperature dependence in a large temperature interval. We estimate that this unusual behavior, which occurs because the current through the weak link is carried by ``polaronic" Andreev states, is measurable in experiments on, e.g., carbon-nanotube based Josepshon junctions.
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