SwePub - search: WFRF:(Shekhter Robert I. 1947)

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1.	Fogel, Nina Ya., et al. (author) Direct evidence for interfacial superconductivity in two-layer semiconducting heterostructures 2006 In: Physical Review B. - 1098-0121. ; 73:16 Journal article (peer-reviewed)abstract We have discovered superconductivity in the two-layer semiconducting monochalcogenide heterostrutures PbTe/PbS, PbTe/PbSe and PbTe/YbS. By comparing data from two-layer samples with data from single monochalcogenide films we conclude that the superconductivity is connected with the interface between the two semiconductors. Evidence for the low dimensional nature of the superconducting interlayer is presented and a model that explains the appearance of single-interface superconductivity is proposed.
2.	Fogel, Nina Ya. 1938, et al. (author) Interfacial superconductivity in semiconducting monochalcogenide superlattices 2002 In: Physical Review B - Condensed Matter and Materials Physics. - 2469-9950 .- 2469-9969. ; 66:17, s. 174513(11pp.)- Journal article (peer-reviewed)abstract Superconducting and structural properties of superconducting semiconducting multilayers are investigated. These layered systems are obtained by epitaxial growth of the isomorphic monochalcogenides of Pb, Sn, and rare-earth elements on a KCl substrate. Some of these compounds are narrow-gap semiconductors (PbTe, PbS, PbSe, SnTe). Layered structures containing one or two narrow-gap semiconductors have a metallic type of conductivity and a transition to a superconducting state at temperatures in the range of 2.56 K. Structures containing only wide-gap semiconductors (YbS, EuS, EuSe) do not demonstrate such properties. All superconducting layered systems are type-II superconductors. The critical magnetic fields and the resistive behavior in the mixed state reveal features characteristic of other layered superconductors. However, data obtained in magnetic fields testify that the period of the superstructure corresponds to half of that obtained from x-ray-diffractometry investigations. This is evidence that the superconducting layers in these samples are confined to the interfaces between two semiconductors. Electron microscopy studies reveal that in the case of epitaxial growth the interfaces contain regular grids of misfit dislocations covering all the interface area. These samples appear to undergo a superconducting transition if they have a metallic type of conductivity in the normal state. Samples with island-type dislocation grids only reveal partial superconducting transitions. The correlations between the appearance of superconductivity and the presence of dislocations, which have been found experimentally, lead to the conclusion that the normal metallic conductivity as well as the superconductivity are induced by the elastic deformation fields created by the misfit dislocation grids. A theoretical model is proposed for the description of the narrow-gap semiconductor metallization, which is due to a band inversion effect and the appearance of electron- or hole-type inversion layers near the interfaces. For different combinations of the semiconductors, such inversion layers in the superlattices can have different shapes and topology. In particular, they can form multiply connected periodic nets having a repetition period coinciding with that of the dislocation grids. Numerical estimates show that such a scenario for the appearance of superconductivity is quite likely. It is shown that the new type of metallic and superconducting nanoscale two-dimensional structures with unusual properties may be obtained from monochalcogenide semiconductors.
3.	Ilinskaya, O. A., et al. (author) Mechanically induced thermal breakdown in magnetic shuttle structures 2018 In: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 20 Journal article (peer-reviewed)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.
4.	Kadigrobov, Anatoli M., 1937, et al. (author) Hot electrons in magnetic point contacts as a photon source 2011 In: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 13 Journal article (peer-reviewed)abstract We propose to use a point contact between a ferromagnetic and a normal metal in the presence of a magnetic field for creating a large inverted spin population of hot electrons in the contact core. The key point of the proposal is that when these hot electrons relax by flipping their spin, microwave photons are emitted, with a frequency tunable by the applied magnetic field. While point contacts are an established technology, their use as a photon source is a new and potentially very useful application. We show that this photon emission process can be detected by means of transport spectroscopy and demonstrate stimulated emission of radiation in the 10–100 GHz range for a model point contact system using a minority-spin ferromagnetic injector. These results can potentially lead to new types of lasers based on spin injection in metals.
5.	Shekhter, Robert I., 1947, et al. (author) Electronic spin working mechanically 2014 In: Fizika Nizkikh Temperatur. - 0132-6414 .- 1816-0328. ; 40:7, s. 775-792 Journal article (peer-reviewed)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.
6.	Shekhter, Robert I., 1947, et al. (author) Subwavelength terahertz spin-flip laser based on a magnetic point-contact array 2011 In: Optics Letters. - 0146-9592 .- 1539-4794. ; 36:12, s. 2381-2383 Journal article (peer-reviewed)abstract We present a theoretical design for a single-mode, truly subwavelength terahertz disk laser based on a nanocomposite gain medium comprising an array of normal-metal/ferromagnetic (FM) point contacts embedded in a thin dielectric layer. Stimulated emission of light occurs due to spin-flip relaxation of spin-polarized electrons injected from the FM side of the contacts. Ultrahigh electrical current densities in the contacts and a dielectric material with a large refractive index, neither condition being achievable in conventional semiconductor media, enables the thresholds of lasing to be overcome for the lowest-order modes of the disk, making single-mode operation possible.
7.	Gorelik, Leonid, 1952, et al. (author) Coulomb promotion of spin-dependent tunneling 2005 In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 95:11 Journal article (peer-reviewed)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.
8.	Gorelik, Leonid, 1952, et al. (author) Giant shot noise due to mechanical transportation of spin-polarized electrons 2008 In: Physical Review B. - 1098-0121. ; 77:17, s. 174304- Journal article (peer-reviewed)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.
9.	Gorelik, Leonid, 1952, et al. (author) Giant super poissonian shot noise in spin-polarized SET structures 2007 In: Low Temperature Physics. ; 33:9, s. 757-761 Journal article (peer-reviewed)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.
10.	Gorelik, Leonid, 1952, et al. (author) Mechanically assisted spin-dependent transport of electrons 2005 In: Physical Review B (Condensed Matter and Materials Physics). - 0163-1829. ; 71:3, s. 35327-1 Journal article (peer-reviewed)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
11.	Gorelik, Leonid, 1952, et al. (author) Shot noise spectroscopy of electronic spin flips in quantum dots 2007 In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 90:19 Journal article (peer-reviewed)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.
12.	Gorelik, Leonid, 1952, et al. (author) Spin-dependent transport of electrons in a shuttle structure 2006 In: Theory of Quantum Transport in Metallic and Hybrid Nanostructures. - Dordrecht : Kluwer Academic Publishers. - 1568-2609. - 9781402047770 ; , s. 307-319 Conference paper (peer-reviewed)
13.	Ilinskaya, O. A., et al. (author) Shuttling of spin polarized electrons in molecular transistors 2016 In: Synthetic Metals. - : Elsevier BV. - 0379-6779. ; 216, s. 83-87 Journal article (peer-reviewed)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.
14.	Ilinskaya, O. A., et al. (author) Spin-polaronic effects in electric shuttling in a single molecule transistor with magnetic leads 2020 In: Physica E-Low-Dimensional Systems & Nanostructures. - : Elsevier BV. - 1386-9477. ; 122 Journal article (peer-reviewed)
15.	Kadigrobov, Anatoli M., 1937, et al. (author) Giant lasing effect in magnetic point contacts and its detection by DC electrical measurements 2011 In: Proc. of SPIE. - 0277-786X. - 9780819484703 ; 7933 Conference paper (peer-reviewed)abstract We propose a new principle for a compact solid-state laser in 1-100 THz regime based on a new mechanism for creating spin-flip processes in ferromagnetic conductors. On the base of this mechanism, a giant lasing effect is predicted. The optical gain is estimated to exceed the optical gain of conventional semiconductor lasers by 4 or 5 orders of magnitude. We propose to use a point contact between ferromagnetic metals in order to create an inverted spin-population of hot electrons in the contact region. While point contact spectroscopy is an established technology the use of magnetic point contacts as a photon source is a new and potentially very useful application. We show that the generated photons conveniently can be detected by measuring the current through the illuminated point contact.
16.	Kadigrobov, Anatoli M., 1937, et al. (author) Joule heating and current-induced instabilities in magnetic nanocontacts 2006 In: Physical Review B. - 1098-0121 .- 1550-235X. ; 74:19 Journal article (peer-reviewed)abstract We consider the electrical current through a magnetic point contact in the limit of a strong inelastic scattering of electrons. In this limit local Joule heating of the contact region plays a decisive role in determining the transport properties of the point contact. We show that if an applied constant bias voltage exceeds a critical value, the stationary state of the system is unstable, and that periodic, nonharmonic oscillations in time of both the electrical current through the contact and the local temperature in the contact region develop spontaneously. Our estimations show that the necessary experimental conditions for observing such oscillations with characteristic frequencies in the range 10(8)-10(9) Hz can easily be met. We also show a possibility to manipulate upon the magnetization direction of a magnetic grain coupled through a point contact to a bulk ferromagnet by exciting the above-mentioned thermal-electric oscillations.
17.	Kadigrobov, Anatoli M., 1937, et al. (author) Microwave-induced spin-flip scattering of electrons in point contacts 2011 In: Low Temperature Physics. - 1063-777X. ; 37:11, s. 925-932 Journal article (peer-reviewed)abstract We investigate resonant interaction of conduction electrons with an electromagnetic field that irradiates a point contact between a ferromagnetic and a normal metal in the presence of a strong magnetic field of order 1 T. We show that electron spin-flips caused by resonant absorption and stimulated emission of photons result in a sharp peak in the magnetic-field dependence of the point-contact resistance. The height of the peak is shown to be directly proportional to the net rate of energy transfer to the electromagnetic field in the point contact due to absorption and stimulated emission of photons. Estimations indicate that our theory can serve as a basis for the explanation of recent experiments [A.M. Kadigrobov et al., New J. Phys. 13, 023007 (2011)].
18.	Krive, Ilya V., et al. (author) Charge and spin effects in mesoscopic Josephson junctions 2004 In: Fizika Nizkikh Temperatur (Kharkov). - 0132-6414. ; 30, s. 554- Journal article (peer-reviewed)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.
19.	Kulinich, Sergeij I., et al. (author) Nanomechanics of a magnetic shuttle device 2014 In: Low temperature physics. - : AIP Publishing. - 1063-777X .- 1090-6517. ; 40:10, s. 1161-1169 Journal article (peer-reviewed)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.
20.	Kulinich, Sergeij I., et al. (author) Single-Electron Shuttle Based on Electron Spin 2014 In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 112:11 Journal article (peer-reviewed)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.
21.	Kulinich, Sergeij I., et al. (author) Umklapp-assisted electron transport oscillations in metal superlattices 2012 In: Physical Review B. - 1098-0121. ; 85:18, s. artikel nr 184202- Journal article (peer-reviewed)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.
22.	Naidyuk, Yu. G., et al. (author) Stimulated emission and absorption of photons in magnetic point contacts 2012 In: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 14 Journal article (peer-reviewed)abstract Point contacts between high anisotropy ferromagnetic SmCo5 and normal metal Cu are used to achieve a strong spin-population inversion in the contact core. Subjected to microwave irradiation in resonance with the Zeeman splitting in Cu, the inverted spin population relaxes through stimulated spin-flip photon emission, detected as peaks in the point-contact resistance. Resonant spin-flip photon absorption is detected as resistance minima, corresponding to sourcing the photon field energy into the electrical circuit. These results demonstrate fundamental mechanisms that are potentially useful in designing metallic spin-based lasers.
23.	Parafilo, A. V., et al. (author) Spin-mediated Photomechanical Coupling of a Nanoelectromechanical Shuttle 2016 In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 117:5 Journal article (peer-reviewed)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.
24.	Shekhter, Robert I., 1947, et al. (author) Electronic Aharonov-Bohm effect induced by quantum vibrations 2006 In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 97:15 Journal article (peer-reviewed)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.
25.	Shekhter, Robert I., 1947, et al. (author) Electronic spin working mechanically (Review Article) 2014 In: Low temperature physics. - : AIP Publishing. - 1063-777X .- 1090-6517. ; 40:7, s. 600-614 Journal article (peer-reviewed)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.
26.	Skorobagatko, G. A., et al. (author) Magnetopolaronic effects in electron transport through a single-level vibrating quantum dot 2011 In: Low Temperature Physics. - 1063-777X. ; 37:12, s. 1032-1037 Journal article (peer-reviewed)abstract Magnetopolaronic effects are considered in electron transport through a single-level vibrating quantum dot subjected to a transverse (to the current flow) magnetic field. It is shown that the effects are most pronounced in the regime of sequential electron tunneling, where a polaronic blockade of the current at low temperatures and an anomalous temperature dependence of the magnetoconductance are predicted. In contrast, for resonant tunneling of polarons the peak conductance is not affected by the magnetic field.
27.	Sonne, Gustav, 1982, et al. (author) Superconducting pumping of nanomechanical vibrations 2008 In: Physical Review B. - 1098-0121. ; 78, s. 144501- Journal article (peer-reviewed)abstract We demonstrate that a supercurrent can pump energy from a battery that provides a voltage bias into nanomechanical vibrations. Using a device containing a nanowire Josephson weak link as an example we show that a nonlinear coupling between the supercurrent and a static external magnetic field leads to a Lorentz force that excites bending vibrations of the wire at resonance conditions. We also demonstrate the possibility to achieve more than one regime of stationary nonlinear vibrations and how to detect them via the associated dc Josephson currents and we discuss possible applications of such a multistable nanoelectromechanical dynamics.
28.	Aharony, A., et al. (author) Effects of Different Lead Magnetizations on the Datta-Das Spin Field-Effect Transistor 2019 In: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 123:17, s. 11094-11100 Journal article (peer-reviewed)abstract A Datta-Das spin field-effect transistor is built of a one-dimensional weak link, with Rashba spin-orbit interactions (SOIs), which connects two magnetized reservoirs. The particle and spin currents between the two reservoirs are calculated to lowest order in the tunneling through the weak link and in the wide-band approximation, with emphasis on their dependence on the origins of the "bare" magnetizations in the reservoirs. The SOI is found to generate magnetization components in each reservoir, which rotate in the plane of the electric field (generating the SOI) and the weak link, only if the "bare" magnetization of the other reservoir has a nonzero component in that plane. The SOI affects the charge current only if both reservoirs are polarized. The charge current is conserved, but the transverse rotating magnetization current is not conserved because the SOI in the weak link generates extra spin polarizations which are injected into the reservoirs.
29.	Aharony, A., et al. (author) Electric and magnetic gating of Rashba-active weak links 2018 In: Physical Review B. - 2469-9950. ; 97:22 Journal article (peer-reviewed)abstract In a one-dimensional weak-link wire the spin-orbit interaction (SOI) alone cannot generate a nonzero spin current. We show that a Zeeman field acting in the wire in conjunction with the Rashba SOI there does yield such a current, whose magnitude and direction depend on the direction of the field. When this field is not parallel to the effective field due to the SOI, both the charge and the spin currents oscillate with the length of the wire. Measuring the oscillating anisotropic magnetoresistance can thus yield information on the SOI strength. These features are tuned by applying a magnetic and/or an electric field, with possible applications to spintronics.
30.	Bahrova, O. M., et al. (author) Cooling of nanomechanical vibrations by Andreev injection 2022 In: Low Temperature Physics. - : AIP Publishing. - 1063-777X .- 1090-6517. ; 48:6, s. 476-482 Journal article (peer-reviewed)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.
31.	Bahrova, O. M., et al. (author) Nanomechanics driven by the superconducting proximity effect 2022 In: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 24:3 Journal article (peer-reviewed)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.
32.	Entin-Wohlman, O., et al. (author) Magnetization near a constriction between BCS superconductors by spin-dependent tunneling 2023 In: Physical Review B. - 2469-9950. ; 108:18 Journal article (peer-reviewed)abstract Spin-dependent electron tunneling through a voltage-biased microconstriction between two bulk superconductors is shown to create a dc component of the magnetization in the superconductors near the constriction and an ac Josephson-like spin current. The static magnetization appears in one superconductor even if the other is replaced by a normal conductor. Although spin-dependent tunneling generates quantum spin fluctuations also in the absence of a bias, the formation of spin-triplet Cooper pairs, necessary for the creation of magnetization, is blocked by destructive interference between different quasielectron and quasihole tunneling channels, unless there is an asymmetry between the tunneling densities of states for electrons and holes. Breaking the symmetry in the electron-hole tunnel density of states and creating electron-hole tunneling imbalance by biasing the device destroys the destructive interference and enables triplet Cooper-pair formation. As a result, magnetizing the superconductor becomes possible. The role of the voltage in lifting the blockade hindering the spin-triplet Cooper pair formation is an example of an electrically controlled dissipationless spintronic phenomenon.
33.	Entin-Wohlman, O., et al. (author) Photovoltaic effect generated by spin-orbit interactions 2020 In: Physical Review B. - 2469-9950. ; 101:12 Journal article (peer-reviewed)abstract An AC electric field applied to a junction comprising two spin-orbit coupled weak links connecting a quantum dot to two electronic terminals is proposed to induce a DC current and to generate a voltage drop over the junction if it is a part of an open circuit. This photovoltaic effect requires a junction in which mirror reflection symmetry is broken. Its origin lies in the different ways inelastic processes modify the reflection of electrons from the junction back into the two terminals, which leads to uncompensated DC transport. The effect can be detected by measuring the voltage drop that is built up due to that DC current. This voltage is an even function of the frequency of the AC electric field.
34.	Fedorets, Dmytro, 1976, et al. (author) Quantum shuttle phenomena in a nanoelectromechanical single-electron transistor 2004 In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 92 Journal article (peer-reviewed)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.
35.	Fedorets, Dmytro, 1976, et al. (author) Spintronics of a nanoelectromechanical shuttle 2005 In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 95:5 Journal article (peer-reviewed)
36.	Gorelik, Leonid, 1952, et al. (author) Resonant microwave properties of a voltage-biased single-Cooper-pair transistor 2004 In: Physical Review B. ; 69, s. 094516 - Journal article (peer-reviewed)
37.	Gorelik, Leonid, 1952, et al. (author) Spin-controlled nanoelectromechanics in magnetic NEM-SET systems 2005 In: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 7 Journal article (peer-reviewed)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.
38.	Gorelik, Leonid, 1952, et al. (author) Suppression of thermal fluctuations of nanomechanical resonator (ground state cooling) by thermally activated electronic flow 2011 In: 21st International Conference on Noise and Fluctuations, ICNF 2011; Toronto, ON; 12 June 2011 through 16 June 2011. - 9781457701924 ; , s. 223-226 Conference paper (peer-reviewed)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.
39.	Gorelik, Leonid Y., 1952, et al. (author) Suppression of thermal fluctuations of nanomechanical resonator (ground state cooling) by thermally activated electronic flow 2011 In: 21st International Conference on Noise and Fluctuations, ICNF 2011; Toronto, ON; 12 June 2011 through 16 June 2011. - 9781457701924 ; , s. 223-226 Conference paper (peer-reviewed)
40.	Ilinskaya, O. A., et al. (author) Coulomb effects on thermally induced shuttling of spin-polarized electrons 2019 In: Low Temperature Physics. - : AIP Publishing. - 1063-777X .- 1090-6517. ; 45:9, s. 1032-1040 Journal article (peer-reviewed)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.
41.	Ilinskaya, O. A., et al. (author) Coulomb-promoted spintromechanics in magnetic shuttle devices 2019 In: Physical Review B. - 2469-9950. ; 100:4 Journal article (peer-reviewed)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.
42.	Ilinskaya, O. A., et al. (author) Magnetically controlled single-electron shuttle 2015 In: Low temperature physics. - : AIP Publishing. - 1063-777X .- 1090-6517. ; 41:1, s. 70-74 Journal article (peer-reviewed)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.
43.	Ilinskaya, O. A., et al. (author) Polaronic suppression of shuttle vibrations 2023 In: Low Temperature Physics. - : AIP Publishing. - 1063-777X .- 1090-6517. ; 49:1, s. 75-80 Journal article (peer-reviewed)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.
44.	Jonson, Mats, 1947, et al. (author) DC spin generation by junctions with AC driven spin-orbit interaction 2019 In: Physical Review B. - 2469-9950. ; 100:11 Journal article (peer-reviewed)abstract An unbiased one-dimensional weak link between two terminals, subjected to the Rashba spin-orbit interaction caused by an AC electric field which rotates periodically in the plane perpendicular to the link, is shown to inject spin-polarized electrons into the terminals. The injected spin polarization has a DC component along the link and a rotating transverse component in the perpendicular plane. In the low-rotation-frequency regime, these polarization components are proportional to the frequency. The DC component of the polarization vanishes for a linearly polarized electric field.
45.	Jonson, Mats, 1947, et al. (author) Mechanically driven spin-orbit-active weak links 2018 In: Fizika Nizkikh Temperatur. - : AIP Publishing. - 0132-6414. ; 44:12, s. 1577-1581 Journal article (peer-reviewed)abstract We show that new functionality of spin-orbit-active electronic weak links can be achieved by their time-dependent mechanical deformation. As an illustration we use a simple model to calculate the electronic spin current generated by rotating a bent spin-orbit-active nanowire coupled to bulk metallic leads. © Institute for Low Temperature Physics and Engineering. All rights reserved.
46.	Jonsson, Magnus, 1979, et al. (author) Electromechanical instabilities of suspended carbon nanotubes-multi mode excitations 2007 In: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 9 Journal article (peer-reviewed)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.
47.	Jonsson, Magnus, 1979, et al. (author) Electromechanical instability in suspended carbon nanotubes 2005 In: Nano Letters. - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 5:6, s. 1165-1169 Journal article (peer-reviewed)
48.	Jonsson, Magnus, 1979, et al. (author) Self-organization of irregular nanoelectromechanical vibrations in multimode shuttle structures 2008 In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 100:18 Journal article (peer-reviewed)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.
49.	Kadigrobov, Anatoli M., 1937, et al. (author) Current-induced magnetic superstructures in exchange-spring devices 2012 In: Physical Review B. - 1098-0121. ; 86:1 Journal article (peer-reviewed)abstract We investigate the potential to use a magnetothermoelectric instability that may be induced in a mesoscopic magnetic multilayer (F/f/F) to create and control magnetic superstructures. In the studied multilayer two strongly ferromagnetic layers (F) are coupled through a weakly ferromagnetic spacer (f) by an “exchange spring” with a temperature-dependent “spring constant” that can be varied by Joule heating caused by an electrical dc current. We show that in the current-in-plane configuration a distribution of the magnetization, which is homogeneous in the direction of the current flow, is unstable in the presence of an external magnetic field if the length L of the sample in this direction exceeds some critical value Lc∼10 μm. This spatial instability results in the spontaneous formation of a moving domain of magnetization directions, the length of which can be controlled by the bias voltage in the limit L≫Lc. Furthermore, we show that in such a situation the current-voltage characteristic has a plateau with hysteresis loops at its ends and demonstrate that if biased in the plateau region the studied device functions as an exponentially precise current stabilizer.
50.	Kadigrobov, Anatoli M., 1937, et al. (author) Dynamics of current-induced magnetic superstructures in exchange-spring devices 2012 In: Low Temperature Physics. - : AIP Publishing. - 1063-777X .- 1090-6517. ; 38:7, s. 626-632 Journal article (peer-reviewed)abstract Thermoelectric manipulation of the magnetization of a magnetic layered stack in which a low-Curie temperature magnet is sandwiched between two strong magnets (exchange spring device) is considered. Controllable Joule heating produced by a current flowing in the plane of the magnetic stack (CIP configuration) induces a spatial magnetic and thermal structure along the current flow - a magnetothermal-electric domain (soliton). We show that such a structure can experience oscillatory in time dynamics if the magnetic stack is incorporated into an electric circuit in series with an inductor. The excitation of these magnetothermionic oscillations follow the scenario either of “soft” or “hard” instability: in the latter case oscillations arise if the initial perturbation is large enough. The frequency of the temporal oscillations is of the order of 105–107s–1 for current densities j∼106–107A/cm2.

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