| 1. |
- Fedorets, Dmytro, 1976, et al.
(författare)
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Quantum shuttle phenomena in a nanoelectromechanical single-electron transistor
- 2004
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 92
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Tidskriftsartikel (refereegranskat)abstract
- An analytical analysis of quantum shuttle phenomena in a nanoelectromechanical single-electron transistor has been performed in the realistic case, when the electron tunneling length is much greater than the amplitude of the zero point oscillations of the central island. It is shown that when the dissipation is below a certain threshold value, the vibrational ground state of the central island is unstable. The steady state into which this instability develops is studied. It is found that if the electric field E between the leads is much greater than a characteristic value E-q, the quasiclassical shuttle picture is recovered, while if E0) shuttle vibrations.
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| 2. |
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| 3. |
- Gorelik, Leonid, 1952, et al.
(författare)
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Coulomb promotion of spin-dependent tunneling
- 2005
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 95:11
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Tidskriftsartikel (refereegranskat)abstract
- We study transport of spin-polarized electrons through a magnetic single-electron transistor (SET) in the presence of an external magnetic field. Assuming the SET to have a nanometer size central island with a single-electron level we find that the interplay on the island between coherent spin-flip dynamics and Coulomb interactions can make the Coulomb correlations promote rather than suppress the current through the device. We find the criteria for this new phenomenon-Coulomb promotion of spin-dependent tunneling-to occur. © 2005 The American Physical Society.
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| 4. |
- Gorelik, Leonid, 1952, et al.
(författare)
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Giant shot noise due to mechanical transportation of spin-polarized electrons
- 2008
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Ingår i: Physical Review B. - 1098-0121. ; 77:17, s. 174304-
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Tidskriftsartikel (refereegranskat)abstract
- We show that single-electron "shuttling" of electrons in a magnetic nanoelectromechanical single-electron transistor device can be an efficient tool for studying electron spin-flip relaxation on quantum dots. The reason is traced to a spin blockade of the mechanically aided shuttle current that occurs in devices with highly polarized and collinearly magnetized leads. This results in giant peaks in the shot-noise spectral function, wherein the peak heights are only limited by the rate of electronic spin flips. Therefore, we show that nanomechanical spectroscopy of the spin-flip rate is possible, allowing spin-flip relaxation times as long as 10 mu s to be detected.
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| 5. |
- Gorelik, Leonid, 1952, et al.
(författare)
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Giant super poissonian shot noise in spin-polarized SET structures
- 2007
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Ingår i: Low Temperature Physics. ; 33:9, s. 757-761
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Tidskriftsartikel (refereegranskat)abstract
- We study transport of spin-polarized electrons through a magnetic single-electron transistor (SET) in the presence of an external magnetic field. Assuming the SET to have a nanometer-sized central island with a single electron level, we find that the zero-frequency shot noise diverges as the on-dot spin-flip rate goes to zero, provided the source and drain leads are completely polarized in the same direction. We present an analytical expression for the low-frequency super-Poissonian shot noise that allows one to specify the necessary conditions for the experimental observation of the phenomenon. (c) 2007 American Institute of Physics.
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| 6. |
- Gorelik, Leonid, 1952, et al.
(författare)
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Mechanically assisted spin-dependent transport of electrons
- 2005
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Ingår i: Physical Review B (Condensed Matter and Materials Physics). - 0163-1829. ; 71:3, s. 35327-1
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Tidskriftsartikel (refereegranskat)abstract
- Spin-dependent tunneling of electrons through magnetic nanostructures containing a mechanically movable quantum dot is considered. It is shown that the mechanically assisted current can be made strongly sensitive to an external magnetic field, leading to a giant magnetotransmittance effect for weak external fields of order 1-10 Oe
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| 7. |
- Gorelik, Leonid, 1952, et al.
(författare)
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Shot noise spectroscopy of electronic spin flips in quantum dots
- 2007
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 90:19
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Tidskriftsartikel (refereegranskat)abstract
- Spin decoherence and spin flips crucially affect the tunneling transport of spin-polarized electrons through a quantum dot connected to magnetic leads. Here, the authors show that the low-frequency shot noise in such structures diverges as the spin relaxation rate for electrons on the dot goes to zero, reaching giant super-Poissonian values for realistic spin-flip rates. It is also shown that combined measurements of the average current and the shot noise as a function of bias voltage and external magnetic field offer a spectroscopic tool for studying electronic spin relaxation rates in this system.
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| 8. |
- Gorelik, Leonid, 1952, et al.
(författare)
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Spin-controlled nanoelectromechanics in magnetic NEM-SET systems
- 2005
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Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- We present a theory of the nanoelectromechanical coupling in a magnetic nanoelectromechanical single-electron tunnelling (NEM-SET) device, where a nanometre-sized metallic cluster or 'dot' is suspended between two magnetic leads. In this device, the spin projections of the tunnelling electrons, which can be manipulated by an external magnetic field, control the strength of the tunnel current. The magnitude of the current, in turn, determines the power that can be supplied to the vibrational degree of freedom of the suspended cluster. The electromechanical instability that occurs in the system if the dissipation rate of the mechanical cluster vibration energy is slow enough, is shown to strongly depend on the external magnetic field. As a result different regimes of 'shuttle' vibrations appear and are analysed. The strength of the magnetic field required to control the nanomechanical vibrations decreases as the tunnel resistance of the device increases and can be as low as 10 gauss for gigaohm tunnel structures.
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| 9. |
- Isacsson, Andreas, 1975, et al.
(författare)
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Electronic superlattices in corrugated graphene
- 2008
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Ingår i: Physical Review B. - 1098-0121. ; 77:3, s. 035423-
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Tidskriftsartikel (refereegranskat)abstract
- We theoretically investigate electron transport through corrugated graphene ribbons and show how the ribbon curvature leads to an electronic superlattice with a period set by the corrugation wavelength. Transport through the ribbon depends sensitively on the superlattice band structure which, in turn, strongly depends on the geometry of the deformed sheet. In particular, we find that for ribbon widths where the transverse level separation is comparable to the band edge energy, a strong current switching occurs as a function of an applied back gate voltage. Thus, artificially corrugated graphene sheets or ribbons can be used for the study of Dirac fermions in periodic potentials. Furthermore, this provides an additional design degree of freedom for graphene-based electronics.
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| 10. |
- Jonsson, Magnus, 1979, et al.
(författare)
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Electromechanical instabilities of suspended carbon nanotubes-multi mode excitations
- 2007
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Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- We investigate theoretically the occurrence of ‘shuttle-like’ electromechanical instabilities in systems where charge transfer processes interact with several mechanical degrees of freedom simultaneously. In particular we consider the excitation of the multiple bending modes of a suspended carbon nanotube (CNT) due to the injection of current from the tip of a scanning tunnelling microscope (STM) into the suspended part of the tube. With respect to the shuttle instability, we show that the different bending modes can be treated independently in the limit of weak electromechanical coupling. As a result one or more modes—depending on the strength of the tunnel coupling between the CNT and the STM-tip—can be unstable.We find that it is possible to selectively excite a specific mode by tuning the distance between the STM-tip and the CNT. Furthermore, we have investigated the stable (limit cycle) regime that develops as a result of the shuttle instability when only one bending mode is unstable.
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