| 1. |
- Ilinskaya, O. A., et al.
(författare)
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Coulomb effects on thermally induced shuttling of spin-polarized electrons
- 2019
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Ingår i: Low Temperature Physics. - : AIP Publishing. - 1063-777X .- 1090-6517. ; 45:9, s. 1032-1040
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Tidskriftsartikel (refereegranskat)abstract
- A thermally driven single-electron transistor with magnetic leads and a movable central island (a quantum dot) subject to an external magnetic field is considered. The possibility of a mechanical instability caused by magnetic exchange interactions between spin-polarized electrons in this system was studied by the density matrix method. We proved analytically that for noninteracting electrons in the dot there is no such mechanical instability. However, for finite strengths of the Coulomb correlations in the dot we numerically found critical magnetic fields separating regimes of mechanical instability and electron shuttling on the one hand and damped mechanical oscillations on the other. It was shown that thermally induced magnetic shuttling of spin-polarized electrons is a threshold phenomenon, and the dependence of the threshold bias temperature on model parameters was calculated.
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| 2. |
- 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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| 3. |
- Ilinskaya, O. A., et al.
(författare)
-
Coulomb-promoted spintromechanics in magnetic shuttle devices
- 2019
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Ingår i: Physical Review B. - 2469-9950. ; 100:4
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Tidskriftsartikel (refereegranskat)abstract
- Exchange forces on the movable dot ("shuttle") in a magnetic shuttle device depend on the parity of the number of shuttling electrons. The performance of such a device can therefore be tuned by changing the strength U of Coulomb correlations to block or unblock parity fluctuations. We show that by increasing U the spintromechanics of the device crosses over, at U = U-c(T), from a mechanically stable regime to a regime of spin-induced shuttle instabilities (neglecting electric forces). This is due to enhanced spin-dependent mechanical forces as parity fluctuations are reduced by a Coulomb blockade of tunneling and demonstrates that single-electron manipulation of single-spin controlled nanomechanics is possible.
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| 4. |
- Ilinskaya, O. A., et al.
(författare)
-
Magnetically controlled single-electron shuttle
- 2015
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Ingår i: Low temperature physics. - : AIP Publishing. - 1063-777X .- 1090-6517. ; 41:1, s. 70-74
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Tidskriftsartikel (refereegranskat)abstract
- A theory of single-electron shuttling in an external magnetic field in nanoelectromechanical system with magnetic leads is presented. We consider partially spin-polarized electrons in the leads and electron transport in both the Coulomb blockade regime and in the limit of large bias voltages when the Coulomb blockade is lifted. The influence of the degree of spin polarization on shuttle instability is considered. It is shown that there is certain degree of spin polarization above which the magnetic field ceases to control electron transport. In the Coulomb blockade regime the depend- ence of the threshold magnetic field, which separates the “shuttle” and vibron regimes, on the degree of polarization is evaluated. The possibility of re-entrant transitions to the shuttle phase is discussed.
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| 5. |
- Ilinskaya, O. A., et al.
(författare)
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Mechanically induced thermal breakdown in magnetic shuttle structures
- 2018
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Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 20
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Tidskriftsartikel (refereegranskat)abstract
- A theory of a thermally induced single-electron 'shuttling' instability in a magnetic nano-mechanical device subject to an external magnetic field is presented in the Coulomb blockade regime of electron transport. The model magnetic shuttle device considered comprises a movable metallic grain suspended between two magnetic leads, which are kept at different temperatures and assumed to be fully spin-polarized with anti-parallel magnetizations. For a given temperature difference shuttling is found to occur for a region of external magnetic fields between a lower and an upper critical field strength, which separate the shuttling regime from normal small-amplitude 'vibronic' regimes. We find that (i) the upper critical magnetic field saturates to a constant value in the high temperature limit and that the shuttle instability domain expands with a decrease of the temperature; (ii) the lower critical magnetic field depends not only on the temperature-independent phenomenological friction coefficient used in the model but also on intrinsic friction (which vanishes in the high temperature limit) caused by magnetic exchange forces and electron tunneling between the quantum dot and the leads. The feasibility of using thermally driven magnetic shuttle systems to harvest thermal breakdown phenomena is discussed.
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| 6. |
- Ilinskaya, O. A., et al.
(författare)
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Polaronic suppression of shuttle vibrations
- 2023
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Ingår i: Low Temperature Physics. - : AIP Publishing. - 1063-777X .- 1090-6517. ; 49:1, s. 75-80
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Tidskriftsartikel (refereegranskat)abstract
- A re-entrant behavior of electron shuttling is shown to occur in a nanoelectromechanical transistor made of magnetic material where spin-polarized electrons are injected into a quantum dot with a single electron level split into two by an external magnetic field. A suppression of shuttle vibrations occurs at a certain value of a bias voltage that starts to allow for transport also through the upper energy level of the dot, while for a further increase of the voltage shuttling recovers. The effect is due to a time-dependent polaronic shift of the dot energy level, which results in a reduction of the supply of electric power to the mechanical motion.
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| 7. |
- Ilinskaya, O. A., et al.
(författare)
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Shuttling of spin polarized electrons in molecular transistors
- 2016
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Ingår i: Synthetic Metals. - : Elsevier BV. - 0379-6779. ; 216, s. 83-87
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Tidskriftsartikel (refereegranskat)abstract
- Shuttling of electrons in single-molecule transistors with magnetic leads in the presence of an external magnetic field is considered theoretically. For a current of partially spin-polarized electrons a shuttle instability is predicted to occur for a finite interval of external magnetic field strengths. The lower critical magnetic field is determined by the degree of spin polarization and it vanishes as the spin polarization approaches 100%. The feasibility of detecting magnetic shuttling in a C-60-based molecular transistor with magnetic (Ni) electrodes is discussed (Pasupathy et al. (2004) [7]). (C) 2015 Elsevier B.V. All rights reserved.
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| 8. |
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