SwePub - sökning: WFRF:(Gorelik Leonid 1952)

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1.	Atalaya, Juan, 1981, et al. (författare) Spintronics-based mesoscopic heat engine 2012 Ingår i: Physical Review B - Condensed Matter and Materials Physics. - 2469-9950 .- 2469-9969. ; 85:24, s. Article Number: 245309 - Tidskriftsartikel (refereegranskat)abstract We consider a nanowire suspended between two spin-polarized leads and subjected to a nonuniform magnetic field. We show that a temperature drop between the leads can significantly affect the nanowire dynamics. In particular, it is demonstrated that, under certain conditions, the stationary distribution of the mechanical subsystem has a Boltzmann form with an effective temperature, which is lower than the temperature of the "cold" lead; 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.
2.	Bahrova, O. M., et al. (författare) Cooling of nanomechanical vibrations by Andreev injection 2022 Ingår i: Low Temperature Physics. - : AIP Publishing. - 1063-777X .- 1090-6517. ; 48:6, s. 476-482 Tidskriftsartikel (refereegranskat)abstract A nanoelectromechanical weak link composed of a carbon nanotube suspended between two normal electrodes in a gap between two superconducting leads is considered. The nanotube is treated as a movable single level quantum dot in which the position-dependent superconducting order parameter is induced due to the Cooper pair tunneling. We show that electron tunneling processes significantly affect the state of the mechanical subsystem. We found that at a given direction of the applied voltage between the electrodes, the stationary state of the mechanical subsystem has a Boltzmann form with an effective temperature dependent on the parameters of the device. As this takes place, the effective temperature can reach significantly small values (cooling effect). We also demonstrate that nanotube fluctuations strongly affect the dc current through the system. The latter can be used to probe the predicted effects in an experiment. Published under an exclusive license by AIP Publishing.
3.	Bahrova, O. M., et al. (författare) Entanglement between charge qubit states and coherent states of nanomechanical resonator generated by ac Josephson effect 2021 Ingår i: Low Temperature Physics. - : AIP Publishing. - 1063-777X .- 1090-6517. ; 47:4, s. 287-293 Tidskriftsartikel (refereegranskat)abstract We considered a nanoelectromechanical system consisting of a movable Cooper-pair box qubit, which is subject to an electrostatic field, and coupled to the two bulk superconductors via tunneling processes. We suggest that qubit dynamics is related to that of a quantum oscillator and demonstrate that a bias voltage applied between superconductors generates states represented by the entanglement of qubit states and coherent states of the oscillator if certain resonant conditions are fulfilled. It is shown that a structure of this entanglement may be controlled by the bias voltage in a way that gives rise to the entanglement incorporating so-called cat-states—the superposition of coherent states. We characterize the formation and development of such states analyzing the entropy of entanglement and corresponding Wigner function. The experimentally feasible detection of the effect by measuring the average current is also considered.
4.	Bahrova, O. M., et al. (författare) Nanomechanics driven by the superconducting proximity effect 2022 Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 24:3 Tidskriftsartikel (refereegranskat)abstract We consider a nanoelectromechanical weak link composed of a carbon nanotube suspended above a trench in a normal metal electrode and positioned in a gap between two superconducting leads. The nanotube is treated as a movable single-level quantum dot (QD) in which the position-dependent superconducting order parameter is induced as a result of Cooper pair tunneling. We show that in such a system, self-sustained bending vibrations can emerge if a bias voltage is applied between normal and superconducting electrodes. The occurrence of this effect crucially depends on the direction of the bias voltage and the relative position of the QD level. We also demonstrate that the nanotube vibrations strongly affect the dc current through the system, a characteristic that can be used for the direct experimental observation of the predicted phenomenon.
5.	Eriksson, Martin, 1989, et al. (författare) Nonresonant high frequency excitation of mechanical vibrations in a graphene based nanoresonator 2015 Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 17 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.
6.	Eriksson, Martin, 1989, et al. (författare) Selective nonresonant excitation of vibrational modes in suspended graphene via vibron-plasmon interaction 2015 Ingår i: 2D Materials. - : IOP Publishing. - 2053-1583. ; 2:4 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.
7.	Fedorets, D., et al. (författare) Quantum precursor of shuttle instability 2004 Ingår i: Fundamental problems of mesoscopic physics / Lerner, I.V. , Altshuler, B.L. , Gefen, Y.. ; , s. 65-73 Bokkapitel (övrigt vetenskapligt/konstnärligt)
8.	Fedorets, Dmytro, 1976, et al. (författare) Quantum shuttle phenomena in a nanoelectromechanical single-electron transistor 2004 Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 92 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.
9.	Fedorets, Dmytro, 1976, et al. (författare) Spintronics of a nanoelectromechanical shuttle 2005 Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 95:5 Tidskriftsartikel (refereegranskat)
10.	Gorelik, Leonid, 1952, et al. (författare) Coulomb promotion of spin-dependent tunneling 2005 Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 95:11 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.
11.	Gorelik, Leonid, 1952, et al. (författare) Giant shot noise due to mechanical transportation of spin-polarized electrons 2008 Ingår i: Physical Review B. - 1098-0121. ; 77:17, s. 174304- 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.
12.	Gorelik, Leonid, 1952, et al. (författare) Giant super poissonian shot noise in spin-polarized SET structures 2007 Ingår i: Low Temperature Physics. ; 33:9, s. 757-761 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.
13.	Gorelik, Leonid, 1952, et al. (författare) Mechanically assisted spin-dependent transport of electrons 2005 Ingår i: Physical Review B (Condensed Matter and Materials Physics). - 0163-1829. ; 71:3, s. 35327-1 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
14.	Gorelik, Leonid, 1952, et al. (författare) Mechanically mediated electron transfer in model metallo-enzyme interfaces 2006 Ingår i: Biosensors and Bioelectronics. - : Elsevier BV. - 0956-5663 .- 1873-4235. ; 22:3, s. 405-408 Tidskriftsartikel (refereegranskat)abstract In this paper, we develop a physical analysis of charge transfer in the model ‘metallo-enzyme’ complex which consists of a synthetic redox-addressed assembly (a ‘reaction center’) hybridized with a quantum dot (a gold nanoparticle) and attached via molecular bridge (a spacer) to the electrode. This artificial system allows us to model electronic transduction in experimental redox ezyme-gold nanoparticle hybrid structure recently reported by Xiao et al. [Xiao, Y., Patolsky, F., Katz, E., Hainfeid, J.F., Willner, I., 2003. Science 299, 1877–1881]. We consider a photosensitive spacer that allows us to control the conductivity of the bridge by light. In this paper we will focus on a special type of nanoelectro-mechanical processes in this system and investigate single electronic effects in there.
15.	Gorelik, Leonid, 1952, et al. (författare) Resonant microwave properties of a voltage-biased single-Cooper-pair transistor 2004 Ingår i: Physical Review B. ; 69, s. 094516 - Tidskriftsartikel (refereegranskat)
16.	Gorelik, Leonid, 1952, et al. (författare) Shot noise spectroscopy of electronic spin flips in quantum dots 2007 Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 90:19 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.
17.	Gorelik, Leonid, 1952, et al. (författare) Spin-controlled nanoelectromechanics in magnetic NEM-SET systems 2005 Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 7 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.
18.	Gorelik, Leonid, 1952, et al. (författare) Spin-dependent transport of electrons in a shuttle structure 2006 Ingår i: Theory of Quantum Transport in Metallic and Hybrid Nanostructures. - Dordrecht : Kluwer Academic Publishers. - 1568-2609. - 9781402047770 ; , s. 307-319 Konferensbidrag (refereegranskat)
19.	Gorelik, Leonid, 1952, et al. (författare) Suppression of thermal fluctuations of nanomechanical resonator (ground state cooling) by thermally activated electronic flow 2011 Ingår i: 21st International Conference on Noise and Fluctuations, ICNF 2011; Toronto, ON; 12 June 2011 through 16 June 2011. - 9781457701924 ; , s. 223-226 Konferensbidrag (refereegranskat)abstract We consider a doubly clamped suspended metallic carbon nanotube in which extra charge is injected from the tipof a scanning tunneling microscopy (STM). Our analysis shows that the quantum superposition between the different inelastic electronic tunneling paths can be controlled by the bias voltage. In particular, we find that below Coulomb blockade threshold the vibron emission induced by thermally activated electron transportation can be significantly reduced in comparison to the vibron absorption. As a consequence a net suppression of the thermal fluctuations ("cooling") of the vibrational degrees of freedom can be achieved. © 2011 IEEE.
20.	Gorelik, Leonid Y., 1952, et al. (författare) Suppression of thermal fluctuations of nanomechanical resonator (ground state cooling) by thermally activated electronic flow 2011 Ingår i: 21st International Conference on Noise and Fluctuations, ICNF 2011; Toronto, ON; 12 June 2011 through 16 June 2011. - 9781457701924 ; , s. 223-226 Konferensbidrag (refereegranskat)
21.	Jonsson, Magnus, 1979, et al. (författare) Electromechanical instabilities of suspended carbon nanotubes-multi mode excitations 2007 Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 9 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.
22.	Jonsson, Magnus, 1979, et al. (författare) Electromechanical instability in suspended carbon nanotubes 2005 Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 5:6, s. 1165-1169 Tidskriftsartikel (refereegranskat)
23.	Jonsson, Magnus, 1979, et al. (författare) Self-organization of irregular nanoelectromechanical vibrations in multimode shuttle structures 2008 Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 100:18 Tidskriftsartikel (refereegranskat)abstract We investigate theoretically multimode electromechanical "shuttle" instabilities in dc voltage-biased nanoelectromechanical single-electron tunneling devices. We show that initially irregular (quasiperiodic) oscillations that occur as a result of the simultaneous self-excitation of several mechanical modes with incommensurable frequencies self-organize into periodic oscillations with a frequency corresponding to the eigenfrequency of one of the unstable modes. This effect demonstrates that a local probe can selectively excite global vibrations of extended objects.
24.	Kabir, Mohammad, 1974, et al. (författare) Giant field effect in self-assembled metallo-organic nanoscale networks 2005 Ingår i: Physical Review B. ; 72, s. 235424- Tidskriftsartikel (refereegranskat)abstract Three-terminal devices have been produced by self-assembly of chemically stabilized gold clusters of 57 nm in diameter in a nanogap between the source and drain electrodes on top of an electrostatic gate made of oxidized aluminium. The conductivity of the devices with the agglomerates of clusters, self-assembled in the gap, was modulated substantially by the electric field of the gate. The effect is attributed to the mechanical deformation of the organic tunneling barriers between the gold clusters under the influence of Coulomb forces. A peculiar interplay between the mechanical deformations caused by the gate and the source-drain voltages leads to unusual current-voltage characteristics of the devices. A phenomenological theory based on these ideas has been developed.
25.	Kiselev, M. N., et al. (författare) Kondo Force in Shuttling Devices: Dynamical Probe for a Kondo Cloud 2013 Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 110:6 Tidskriftsartikel (refereegranskat)abstract Abstract: We consider the electromechanical properties of a single-electronic device consisting of a movable quantum dot attached to a vibrating cantilever, forming a tunnel contact with a nonmovable source electrode. We show that the resonance Kondo tunneling of electrons amplifies exponentially the strength of nanoelectromechanical (NEM) coupling in such a device and make the latter insensitive to mesoscopic fluctuations of electronic levels in a nanodot. It is also shown that the study of a Kondo-NEM phenomenon provides additional (as compared with standard conductance measurements in a nonmechanical device) information on retardation effects in the formation of a many-particle cloud accompanying the Kondo tunneling. A possibility for superhigh tunability of mechanical dissipation as well as supersensitive detection of mechanical displacement is demonstrated.
26.	Krive, Ilya V., et al. (författare) Chiral symmetry breaking and the Josephson current in a ballistic superconductor-quantum wire-superconductor junction 2004 Ingår i: Fizika Nizkikh Temperatur. - : AIP Publishing. - 0132-6414 .- 1816-0328. ; 30:5, s. 398-404 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.
27.	Krive, Ilya V., et al. (författare) Rashba spin-orbit interaction in a ballistic Josephson junction 2006 Ingår i: Theory of Quantum Transport in Metallic and Hybrid Nanostructures. - Dordrecht : Kluwer Academic Publishers. - 1568-2609. - 9781402047770 ; , s. 215-228 Konferensbidrag (refereegranskat)
28.	Kulinich, S.I., et al. (författare) Cooling of mechanical vibrations by heat flow 2018 Ingår i: Low Temperature Physics. - : AIP Publishing. - 1063-777X .- 1090-6517. ; 44:12, s. 1232-1232 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.
29.	Kulinich, S. I., et al. (författare) Nanomechanical pumping of Cooper pairs through NS junction 2023 Ingår i: Low Temperature Physics. - 1063-777X. ; 49:10, s. 1219-1224 Tidskriftsartikel (refereegranskat)abstract We consider a system consisting of a single-level quantum dot that performs mechanical periodic oscillations between spatially distant normal and superconducting electrodes, approaching them at a distance that allows the exchange of electrons through the vacuum tunnel barrier. Considering that the distance between the electrodes is much greater than the tunneling length, we show that charge pumping occurs in such a nanosystem even when the electrochemical potentials of the electrodes coincide. In this case, the direction of the electron flow is determined by the position of the quantum dot level relative to the electrochemical potential in bulk electrodes. The latter can be controlled by applying a voltage between the ground and the electrodes. It is also shown that the value of the average current is critically sensitive to the strength of the tunnel coupling between the quantum dot and the superconducting electrode, which, in turn, is controlled by the amplitude of mechanical oscillations.
30.	Kulinich, Sergeij I., et al. (författare) Nanomechanics of a magnetic shuttle device 2014 Ingår i: Low temperature physics. - : AIP Publishing. - 1063-777X .- 1090-6517. ; 40:10, s. 1161-1169 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.
31.	Kulinich, Sergeij I., et al. (författare) Single-Electron Shuttle Based on Electron Spin 2014 Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 112:11 Tidskriftsartikel (refereegranskat)abstract A nanoelectromechanical device based on magnetic exchange forces and electron spin flips induced by a weak external magnetic field is suggested. It is shown that this device can operate as a new type of single-electron "shuttle" in the Coulomb blockade regime of electron transport.
32.	Kulinich, Sergeij I., et al. (författare) Umklapp-assisted electron transport oscillations in metal superlattices 2012 Ingår i: Physical Review B. - 1098-0121. ; 85:18, s. artikel nr 184202- Tidskriftsartikel (refereegranskat)abstract We consider a superlattice of parallel metal tunnel junctions with a spatially nonhomogeneous probability for electrons to tunnel. In such structures tunneling can be accompanied by electron scattering that conserves energy but not momentum. In the special case of a tunneling probability that varies periodically with period a in the longitudinal direction, i.e., perpendicular to the junctions, electron tunneling is accompanied by umklapp scattering, where the longitudinal momentum changes by a multiple of h/a. We predict that as a result a sequence of metal-insulator transitions can be induced by an external electric or magnetic field as the field strength is increased.
33.	Nord, Tomas, et al. (författare) Energy pumping in a quantum nanoelectromechanical system 2005 Ingår i: Low Temperature Physics. ; 31, s. 534-537 Tidskriftsartikel (refereegranskat)
34.	Nordenfelt, Anders, et al. (författare) Magnetomotive Instability and Generation of Mechanical Vibrations in Suspended Semiconducting Carbon Nanotubes 2010 Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 12:12 Tidskriftsartikel (refereegranskat)abstract We investigate the electromechanics of a freely suspended semiconducting carbon nanotube subjected to a magnetic field H in the current-biased regime and show that self-excitation of mechanical nanotube vibrations can occur if H exceeds a critical value Hc of the order of 10–100 mT. The effect can be detected by measuring the magnetic field dependence of the time-averaged voltage drop across the nanotube, which has a singularity at H=Hc. We discuss the applications of the device as an active, tuneable radiofrequency oscillator.
35.	Parafilo, A. V., et al. (författare) Kondo effect in a Aharonov-Casher interferometer 2019 Ingår i: Physical Review B. - 2469-9950 .- 2469-9969. ; 100:23 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.
36.	Parafilo, A. V., et al. (författare) Nanomechanics driven by Andreev tunneling 2020 Ingår i: Physical Review B. - 2469-9950 .- 2469-9969. ; 102:23 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.
37.	Parafilo, A. V., et al. (författare) Pumping and Cooling of Nanomechanical Vibrations Generated by Cooper-Pair Exchange 2022 Ingår i: Journal of Low Temperature Physics. - : Springer Science and Business Media LLC. - 0022-2291 .- 1573-7357. ; 210:1-2, s. 150-65 Tidskriftsartikel (refereegranskat)abstract We consider a nanoelectromechanical system composed of a carbon nanotube suspended between two normal leads and coupled to a superconducting scanning tunneling microscope (STM) tip via vacuum tunnel barrier. Treating the nanotube as a single-level quantum dot, it is shown that an applied voltage between the superconducting STM tip and normal leads gives rise to a pumping or a cooling of the mechanical subsystem depending on the direction of the electronic flow. It is also demonstrated that the transition between these two regimes is controlled by the strength of the tunnel coupling between the nanotube and superconducting STM tip and the relative position of the electronic level. Such phenomena are realized due to a specific electromechanical coupling that is fully governed by the quantum dynamics of the Cooper pairs. The amplitude of the self-sustained oscillations in the pumping regime is analyzed numerically, and the effective temperature of the mechanical subsystem in the cooling regime is obtained.
38.	Parafilo, A. V., et al. (författare) Spin-mediated Photomechanical Coupling of a Nanoelectromechanical Shuttle 2016 Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 117:5 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.
39.	Peña-Aza, Milton Eduardo, 1981, et al. (författare) Parametric excitation of dc current in a single-dot shuttle system via spontaneous symmetry breaking 2013 Ingår i: Physical Review B. - 1098-0121. ; 88:3, s. artikel nr 035412- Tidskriftsartikel (refereegranskat)abstract We investigate theoretically the dynamics of a spatially symmetric shuttle system subjected to an ac gate voltage. We demonstrate that in such a system parametric excitation gives rise to mechanical vibrations when the frequency of the ac signal is close to the eigenfrequency of the mechanical subsystem. These mechanical oscillations result in a dc shuttle current in a certain direction due to spontaneous symmetry breaking. The direction of the current is determined by the phase shift between the ac gate voltage and the parametrically excited mechanical oscillations. The dependence of the shuttle current on the dc gate voltage is also analyzed.
40.	Radic, D., et al. (författare) Nanomechanical cat states generated by a dc voltage-driven Cooper pair box qubit 2022 Ingår i: npj Quantum Information. - : Springer Science and Business Media LLC. - 2056-6387. ; 8:1 Tidskriftsartikel (refereegranskat)abstract We study a nanoelectromechanical system consisting of a Cooper pair box qubit performing nanomechanical vibrations between two bulk superconductors. We demonstrate that a bias voltage applied to the superconductors may generate states represented by entanglement between qubit states and quantum 'cat states', i.e. a superposition of the coherent states of the nanomechanical oscillator. We characterize the formation and development of such states in terms of the corresponding Wigner function and entropy of entanglement. Also, we propose an experimentally feasible detection scheme for the effect, in which the average current that attains the specific features created by the entanglement is measured.
41.	Radić, D., et al. (författare) Nanomechanical manipulation of superconducting charge-qubit quantum networks 2024 Ingår i: Physica B: Condensed Matter. - 0921-4526. ; 684 Tidskriftsartikel (refereegranskat)abstract We suggest a nanoelectromechanical setup and corresponding time-protocol for controlling parameters in order to demonstrate nanomechanical manipulation of superconducting charge-qubit quantum network. We illustrate it on an example reflecting important task for quantum information processing — transmission of quantum information between two charge-qubits facilitated by nanomechanics. The setup is based on terminals utilizing the AC Josephson effect between bias voltage-controlled bulk superconductors and mechanically vibrating mesoscopic superconducting grain in the regime of the Cooper pair box, controlled by the gate voltage. The described manipulation of quantum network is achieved by transduction of quantum information between charge-qubits and intentionally built nanomechanical coherent states, which facilitate its transmission between qubits. This performance is achieved using quantum entanglement between electrical and mechanical states.
42.	Radic, D., et al. (författare) Quantum Theory of Magnetoelectromotive Instability in Nanoelectromechanical Systems with Positive Differential Conductance 2013 Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 111:18, s. 5- Tidskriftsartikel (refereegranskat)abstract We consider dc-electronic transport through a nanowire suspended between two normal-metal leads in the presence of an external magnetic field. We show the very mechanism through which such a system, whose stationary current-voltage characteristic is essentially characterized by positive differential conductance, becomes unstable with respect to an onset of self-excited oscillations in electrical transport and mechanical vibrations. The self-excitation mechanism is based on the correlation between the occupancy of the quantized spin-split electronic energy levels inside the nanowire and the velocity of the nanowire with the crucial influence of strong enough retardation effects in magnetomotive coupling coming from mechanical vibrations.
43.	Radic, Danko, 1970, et al. (författare) Self-excited oscillations of charge-spin accumulation due to single-electron tunneling 2010 Ingår i: Physical Review B. - 1098-0121. ; 82:12, s. 125311 (7 pages)- Tidskriftsartikel (refereegranskat)abstract We theoretically study electronic transport through a layer of quantum dots connecting two metallic leads. By the inclusion of an inductor in series with the junction, we show that steady electronic transport in such a system may be unstable with respect to temporal oscillations caused by an interplay between the Coulomb blockade of tunneling and spin accumulation in the dots. When this instability occurs, a new stable regime is reached, where the average spin and charge in the dots oscillate periodically in time. The frequency of these oscillations is typically on the order of 1 GHz for realistic values of the junction parameters.
44.	Radic, Danko, 1970, et al. (författare) Spin-controlled nanomechanics induced by single-electron tunneling 2011 Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 107:23 Tidskriftsartikel (refereegranskat)abstract We consider dc-electronic transport through a nanowire suspended between normal- and spin-polarized metal leads in the presence of an external magnetic field. We show that magnetomotive coupling between the electrical current through the nanowire and vibrations of the wire may result in self-excitation of mechanical vibrations. The self-excitation mechanism is based on correlations between the occupancy of the quantized electronic energy levels inside the nanowire and the velocity of the nanowire. We derive conditions for the occurrence of the instability and find stable regimes of mechanical oscillations.
45.	Radić, D., et al. (författare) Transduction of quantum information from charge qubit to nanomechanical cat-state 2023 Ingår i: Physica B: Condensed Matter. - 0921-4526 .- 1873-2135. ; 665 Tidskriftsartikel (refereegranskat)abstract We suggest a nanoelectromechanical setup and corresponding time-protocol of its manipulation by which we transduce quantum information from charge qubit to nanomechanical cat-state. The setup is based on the AC Josephson effect between bulk superconductors and mechanically vibrating mesoscopic superconducting island in the regime of the Cooper pair box. Starting with a pure state with quantum information initially encoded into superposition of the Cooper pair box states, applying a specially tailored time-protocol upon bias voltage and gate electrodes, we obtain a new pure state with information finally encoded into superposition of nanomechanical coherent states constituting the cat-state. This performance is achieved using quantum entanglement between electrical and mechanical states. Nanomechanical cat-states serve as a “storage” of quantum information, motivated by significantly longer decoherence time with respect to the charge qubit states, from which the information can be transdued back to the charge qubit applying the reverse time-protocol.
46.	Santandrea, Fabio, 1981, et al. (författare) Cooling of Nanomechanical Resonators by Thermally Activated Single-Electron Transport 2011 Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 106:18 Tidskriftsartikel (refereegranskat)abstract We show that the vibrations of a nanomechanical resonator can be cooled to near its quantum ground state by tunneling injection of electrons from a scanning tunneling microscope tip. The interplay between two mechanisms for coupling the electronic and mechanical degrees of freedom results in a bias-voltage-dependent difference between the probability amplitudes for vibron emission and absorption during tunneling. For a bias voltage just below the Coulomb blockade threshold, we find that absorption dominates, which leads to cooling corresponding to an average vibron population of the fundamental bending mode of 0.2.
47.	Santandrea, Fabio, 1981, et al. (författare) Suppression of the stochastic fluctuations of suspended nanowires by temperature-induced single-electron tunneling 2011 Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 13:10 Tidskriftsartikel (refereegranskat)abstract We theoretically investigate the electromechanical properties of freely suspended nanowires that are in tunneling contact with the tip of a scanning tunneling microscope (STM) and two supporting metallic leads. The aim of our analysis is to characterize the fluctuations of the dynamical variables of the nanowire when a temperature drop is maintained between the STM tip and the leads, which are all assumed to be electrically grounded. By solving a quantum master equation that describes the coupled dynamics of electronic and mechanical degrees of freedom, we found that the stationary state of the mechanical oscillator has a Gaussian character, but that the amplitude of its root-mean square center-of-mass fluctuations is smaller than would be expected if the system were coupled only to the leads at thermal equilibrium.
48.	Shekhter, Robert I., 1947, et al. (författare) Electronic Aharonov-Bohm effect induced by quantum vibrations 2006 Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 97:15 Tidskriftsartikel (refereegranskat)abstract Mechanical displacements of a nanoelectromechanical system shift the electron trajectories and hence perturb phase coherent charge transport through the device. We show theoretically that in the presence of a magnetic field such quantum-coherent displacements may give rise to an Aharonov-Bohm-type of effect. In particular, we demonstrate that quantum vibrations of a suspended carbon nanotube result in a positive nanotube magnetoresistance, which decreases slowly with the increase of temperature. This effect may enable one to detect quantum displacement fluctuations of a nanomechanical device.
49.	Shekhter, Robert I., 1947, et al. (författare) Electronic spin working mechanically 2014 Ingår i: Fizika Nizkikh Temperatur. - 0132-6414 .- 1816-0328. ; 40:7, s. 775-792 Tidskriftsartikel (refereegranskat)abstract A single-electron tunneling (SET) device with a nanoscale central island that can move with respect to the bulk source- and drain electrodes allows for a nanoelectromechanical (NEM) coupling between the electrical current through the device and mechanical vibrations of the island. Although an electromechanical "shuttle" in-stability and the associated phenomenon of single-electron shuttling were predicted more than 15 years ago, both theoretical and experimental studies of NEM-SET structures are still carried out. New functionalities based on quantum coherence, Coulomb correlations and coherent electron-spin dynamics are of particular current interest. In this article we present a short review of recent activities in this area.
50.	Shekhter, Robert I., 1947, et al. (författare) Electronic spin working mechanically (Review Article) 2014 Ingår i: Low temperature physics. - : AIP Publishing. - 1063-777X .- 1090-6517. ; 40:7, s. 600-614 Tidskriftsartikel (refereegranskat)abstract A single-electron tunneling (SET) device with a nanoscale central island that can move with respect to the bulk source- and drain electrodes allows for a nanoelectromechanical (NEM) coupling between the electrical current through the device and mechanical vibrations of the island. Although an electromechanical “shuttle” instability and the associated phenomenon of single-electron shuttling were predicted more than 15 years ago, both theoretical and experimental studies of NEM-SET structures are still carried out. New functionalities based on quantum coherence, Coulomb correlations and coherent electron-spin dynamics are of particular current interest. In this article we present a short review of recent activities in this area.

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