| 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. |
- Kadigrobov, Anatoli M., 1937, et al.
(författare)
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Giant lasing effect in magnetic nanoconductors
- 2004
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Ingår i: Europhysics Letters. - : IOP Publishing. - 1286-4854 .- 0295-5075. ; 67:6, s. 948-954
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Tidskriftsartikel (refereegranskat)abstract
- We propose a new principle for a compact solid-state laser in the 1–100 THz regime. This is a frequency range where attempts to fabricate small-size lasers up to now have met severe technical problems. The proposed laser is based on a new mechanism for creating spin-flip processes in ferromagnetic conductors. The mechanism is due to the interaction of light with conduction electrons; the interaction strength, being proportional to the large exchange energy, exceeds the Zeeman interaction by orders of magnitude. On the basis of this interaction, a giant lasing effect is predicted in a system where a population inversion has been created by tunneling injection of spin-polarized electrons from one ferromagnetic conductor to another—the magnetization of the two ferromagnets having different orientations. Using experimental data for ferromagnetic manganese perovskites with nearly 100% spin polarization, we show the laser frequency to be in the range 1–100 THz. The optical gain is estimated to be of order 107 cm−1, which exceeds the gain of conventional semiconductor lasers by 3 or 4 orders of magnitude. A relevant experimental study is proposed and discussed.
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| 3. |
- Krive, Ilya V., et al.
(författare)
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Charge and spin effects in mesoscopic Josephson junctions
- 2004
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Ingår i: Fizika Nizkikh Temperatur (Kharkov). - 0132-6414. ; 30, s. 554-
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Tidskriftsartikel (refereegranskat)abstract
- We consider the charge and spin effects in low dimensional superconducting weak, links. The first part of the review deals with the effects of electron - electron interaction in Superconductor/Luttlnger liquid/Superconductor junctions. The experimental realization of this mesoscopic hybrid system can be the individual single wall carbon nanotube that bridges the gap between two bulk superconductors. The dc Josephson current through a Luttinger liquid is evaluated in the limits of perfectly and poorly transmitting junctions. The relationship between the Josephson effect in a long SNS junction and the Casimir effect is discussed. In the second part of the paper we review the recent results concerning the influence of the Zeeman and Rashba interactions on the thermodynamical properties of ballistic S-QW-S junction fabricated in two dimensional electron gas. It is shown that in magnetically controlled junction there are conditions for resonant Cooper pair transition which results in giant supercurrent through a tunnel junction and a giant magnetic response of a multichannel SNS junction. The supercurrent induced by the joint action of the Zeeman and Rashba interactions in 1D quantum wires connected to bulk superconductors is predicted.
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| 4. |
- Krive, Ilya V., et al.
(författare)
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Chiral symmetry breaking and the Josephson current in a ballistic superconductor-quantum wire-superconductor junction
- 2004
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Ingår i: Fizika Nizkikh Temperatur. - : AIP Publishing. - 0132-6414 .- 1816-0328. ; 30:5, s. 398-404
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Tidskriftsartikel (refereegranskat)abstract
- We evaluate the Josephson current through a quasi-1D quantum wire coupled to bulk superconductors. It Is shown that the interplay of Rashba spin-orbit interaction and Zeeman splitting results in the appearence of a Josephson current even in the absence of any phase difference between the superconductors. In a transparent junction (D [asymptotically equal to] 1) at low temperatures this anomalous supercurrent Jan appears abruptly for a Zeeman splitting of the order of the Andreev level spacing as the magnetic field is varied. In a low transparency (D very much less than 1) junction one has Jan α root D under special (resonance) conditions. In the absence of Zeeman splitting the anomalous supercurrent disappears. We have investigated the influence of dispersion asymmetry induced by the Rashba interaction in quasi-1D quantum wires on the critical Josephson current and have shown that the breakdown of chiral symmetry enhances the supercurrent.
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| 5. |
- Voinova, Marina V., 1958, et al.
(författare)
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On dissipation of quartz crystal microbalance as a mechanical spectroscopy tool
- 2004
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Ingår i: Spectroscopy. - 0712-4813. ; 18:4, s. 537-544
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Tidskriftsartikel (refereegranskat)abstract
- We report on theoretical analysis of dissipative effects in quartz crystal resonator applications to the dynamics of complex biological fluids and soft polymer films. As a mechanical spectroscopy tool, the quartz resonator can probe the storage and loss moduli μ(ω) of a thin material sample in small amplitude oscillations where polymers exhibit linear viscoelasticity. We show how viscosity (internal friction) and slippage (interfacial friction) of the sample affect the acoustical characteristics of the quartz resonator. With respect to biosensor's application, we present rigorous expressions for the resonant frequency and damping of the quartz crystal which allow to quantify friction effects and even distinguish between them in resonator measurements performing on various frequencies. Possible application of the results in electronic nose and electronic tongue sensors is discussed.
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