| 1. |
- Aharony, A., et al.
(författare)
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Effects of Different Lead Magnetizations on the Datta-Das Spin Field-Effect Transistor
- 2019
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Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 123:17, s. 11094-11100
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Tidskriftsartikel (refereegranskat)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.
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| 2. |
- Aharony, A., et al.
(författare)
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Electric and magnetic gating of Rashba-active weak links
- 2018
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Ingår i: Physical Review B. - 2469-9950. ; 97:22
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Tidskriftsartikel (refereegranskat)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.
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| 3. |
- Entin-Wohlman, O., et al.
(författare)
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Magnetization near a constriction between BCS superconductors by spin-dependent tunneling
- 2023
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Ingår i: Physical Review B. - 2469-9950. ; 108:18
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Tidskriftsartikel (refereegranskat)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.
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| 4. |
- Entin-Wohlman, O., et al.
(författare)
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Photovoltaic effect generated by spin-orbit interactions
- 2020
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Ingår i: Physical Review B. - 2469-9950. ; 101:12
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Tidskriftsartikel (refereegranskat)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.
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| 5. |
- 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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| 6. |
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| 7. |
- Fogel, Nina Ya., et al.
(författare)
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Direct evidence for interfacial superconductivity in two-layer semiconducting heterostructures
- 2006
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Ingår i: Physical Review B. - 1098-0121. ; 73:16
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Tidskriftsartikel (refereegranskat)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.
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| 8. |
- Fogel, Nina Ya. 1938, et al.
(författare)
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Interfacial superconductivity in semiconducting monochalcogenide superlattices
- 2002
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Ingår i: Physical Review B - Condensed Matter and Materials Physics. - 2469-9950 .- 2469-9969. ; 66:17, s. 174513(11pp.)-
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Tidskriftsartikel (refereegranskat)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.
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| 9. |
- Gorelik, Leonid, 1952, et al.
(författare)
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Coulomb promotion of spin-dependent tunneling
- 2005
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 95:11
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Tidskriftsartikel (refereegranskat)abstract
- We study transport of spin-polarized electrons through a magnetic single-electron transistor (SET) in the presence of an external magnetic field. Assuming the SET to have a nanometer size central island with a single-electron level we find that the interplay on the island between coherent spin-flip dynamics and Coulomb interactions can make the Coulomb correlations promote rather than suppress the current through the device. We find the criteria for this new phenomenon-Coulomb promotion of spin-dependent tunneling-to occur. © 2005 The American Physical Society.
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| 10. |
- Gorelik, Leonid, 1952, et al.
(författare)
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Giant shot noise due to mechanical transportation of spin-polarized electrons
- 2008
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Ingår i: Physical Review B. - 1098-0121. ; 77:17, s. 174304-
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Tidskriftsartikel (refereegranskat)abstract
- We show that single-electron "shuttling" of electrons in a magnetic nanoelectromechanical single-electron transistor device can be an efficient tool for studying electron spin-flip relaxation on quantum dots. The reason is traced to a spin blockade of the mechanically aided shuttle current that occurs in devices with highly polarized and collinearly magnetized leads. This results in giant peaks in the shot-noise spectral function, wherein the peak heights are only limited by the rate of electronic spin flips. Therefore, we show that nanomechanical spectroscopy of the spin-flip rate is possible, allowing spin-flip relaxation times as long as 10 mu s to be detected.
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