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Tytuł:
Spin-Sensitive Conductance in Magnetically Contacted Graphene Flakes
Autorzy:
Krompiewski, S.
Powiązania:
https://bibliotekanauki.pl/articles/1534101.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.25.Mk
81.05.ue
73.20.-r
Opis:
The aim of this study is to gain a deeper insight into the impact of geometrical dimensions (aspect ratio) and current direction (zigzag vs. armchair) on transport characteristics. It is found that there is a pronounced dependence of the giant magnetoresistance (in setups with 2 ferromagnetic electrodes), as well as the spin polarization of current (in the case of one paramagnetic and one ferromagnetic electrode) on the bias and gate voltages, meaning a possible electrical control of magnetic properties of these quantities.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 835-836
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tunnel Magnetoresistance for Phonon-Assisted Tunneling through Quantum Dots
Autorzy:
Rudziński, W.
Powiązania:
https://bibliotekanauki.pl/articles/1813937.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.25.Mk
73.63.Kv
73.23.Hk
Opis:
Spin-polarized transport through a single-level quantum dot interacting with a local phonon mode is studied in the frame of the nonequilibrium Green-function technique. It is shown that strong electron-phonon interaction gives rise to a significant current suppression, to additional resonance peaks in the differential conductance as well as to oscillations of the tunnel magnetoresistance. Also, a phonon-induced mechanism leading to a minimum in tunnel magnetoresistance at zero bias voltage is explained.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 587-590
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Qubits in Double Quantum Well Structure
Autorzy:
Jakubczyk, P.
Majchrowski, K.
Tralle, I.
Powiązania:
https://bibliotekanauki.pl/articles/1032436.pdf
Data publikacji:
2017-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.25.Mk
74.55.+v
03.67.Bg
Opis:
We propose a new approach to producing the qubits in electron ballistic transport in low-dimensional structures such as double quantum wells or double quantum wires. Next, we examine the possibility to produce quantum entanglement in the framework of the Jaynes-Cummings model and shown that at least in principle, the entanglement can be achieved due to series of "revivals" and "collapses" in the population inversion due to the interaction of a quantized single-mode EM-field with a two-level system.
Źródło:
Acta Physica Polonica A; 2017, 132, 1; 115-117
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spin Switch and Spin Amplifier: Magnetic Bipolar Transistor in the Saturation Regime
Autorzy:
Fabian, J.
Žutić, I.
Powiązania:
https://bibliotekanauki.pl/articles/2038211.pdf
Data publikacji:
2004-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.25.Dc
72.25.Mk
Opis:
It is shown that magnetic bipolar transistors can amplify currents even in the saturation regime, in which both the emitter-base and collector-base junctions are forward biased. The collector current and the current gain can change sign as they depend on the relative orientation of the equilibrium spin in the base and on the nonequilibrium spin in the emitter and collector. The predicted phenomena should be useful for electrical detection of nonequilibrium spins in semiconductors, as well as for magnetic control of current amplification and for current switching.
Źródło:
Acta Physica Polonica A; 2004, 106, 2; 109-118
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermoelectric Effects in Spin Valves Based on Layered Magnetic Structures
Autorzy:
Kunert, H.
Barnaś, J.
Powiązania:
https://bibliotekanauki.pl/articles/1032514.pdf
Data publikacji:
2017-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.25.Mk
65.80.-g
68.65.Ac
Opis:
General aspects of thermoelectric effects in spin valves consisting of two magnetic layers separated by a nonmagnetic spacing layer are considered, with the main focus on the spin Seebeck effects. The Seebeck and spin Seebeck effects are considered in both current-in-plane and current-perpendicular-to-plane geometries. The corresponding thermopower and spin thermopower in the macroscopic limit of electronic transport are also considered. Physical origin of the spin effects is discussed in detail.
Źródło:
Acta Physica Polonica A; 2017, 132, 1; 124-128
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spin-Flip Transitions in Tunneling through a Quantum Dot Coupled to Ferromagnetic Electrodes
Autorzy:
Rudziński, W.
Powiązania:
https://bibliotekanauki.pl/articles/1810526.pdf
Data publikacji:
2009-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.25.Mk
73.63.Kv
73.23.Hk
Opis:
Using nonequilibrium Green function formalism the spin-polarized electronic transport through a quantum dot coupled to ferromagnetic electrodes is studied. Arbitrary Coulomb correlations and spin-flip processes are considered in the dot, for both parallel and antiparallel magnetic configurations of the junction. It is found that spin-flip processes suppress the magnetoresistance between each pair of the threshold bias voltages, thus giving rise to sharp tunnel magnetoresistance maxima at the thresholds. The origin of additional steps in the electric current, splitting of the resonance peaks in the corresponding differential conductance as well as negative differential conductance is also discussed in the context of interplay between tunneling processes and the intradot spin-flip transitions.
Źródło:
Acta Physica Polonica A; 2009, 115, 1; 281-283
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic and Magnetotransport Properties οf Magnetite/Co-Ferrite/Magnetite Trilayers
Autorzy:
Chen, Y.
Ziese, M.
Powiązania:
https://bibliotekanauki.pl/articles/1810529.pdf
Data publikacji:
2009-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.25.-b
72.25.Mk
75.70.-i
Opis:
The magnetic and magnetotransport properties of $Fe_3O_4$/$CoFe_2O_4$/$Fe_3O_4$ trilayers were investigated. The magnetization measurements indicate significant Co diffusion into the bottom magnetite layer. At lower temperatures the magnetoresistance measurements show two clearly separated maxima due to contributions from magnetically hard and soft layers. A tunneling effect was not observed. Comparison of full and minor resistance hysteresis loops did not reveal any significant exchange coupling between the layers, presumably due to diffuse interfaces.
Źródło:
Acta Physica Polonica A; 2009, 115, 1; 284-286
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spin-Polarized Transport through Quantum Dots in the Cotunneling Regime
Autorzy:
Weymann, I.
Powiązania:
https://bibliotekanauki.pl/articles/1813873.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.25.Mk
73.63.Kv
85.75.-d
73.23.Hk
Opis:
The spin-polarized transport through two-level quantum dots weakly coupled to ferromagnetic leads is considered theoretically in the Coulomb blockade regime. It is assumed that the dot is doubly occupied, so that the current flows due to cotunneling through singlet and triplet states of the dot. It is shown that, by sweeping the bias voltage, one can induce a singlet-triplet transition, which depends on the magnetic configuration of the system and leads to nontrivial bias dependence of both the differential conductance and tunnel magnetoresistance.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 529-532
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Inelastic Electron Tunneling Spectroscopy of a Mn Dimer
Autorzy:
Delgado, F.
Fernández-Rossier, J.
Powiązania:
https://bibliotekanauki.pl/articles/1419512.pdf
Data publikacji:
2012-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.25.Pn
71.70.Gm
72.10.Bg
72.25.Mk
Opis:
A scanning tunneling microscope can probe the inelastic spin excitations of single magnetic atoms in a surface via spin-flip assisted tunneling. A particular and intriguing case is the Mn dimer case. We show here that the existing theories for inelastic transport spectroscopy do not explain the observed spin transitions when both atoms are equally coupled to the scanning tunneling microscope tip and the substrate, the most likely experimental situation. The hyperfine coupling to the nuclear spins is shown to lead to a finite excitation amplitude, but the physical mechanism leading to the large inelastic signal observed is still unknown. We discuss some other alternatives that break the symmetry of the system and allow for larger excitation probabilities.
Źródło:
Acta Physica Polonica A; 2012, 122, 2; 304-306
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spin Hall and Edelstein Effects in Metallic Films
Autorzy:
Borge, J.
Gorini, C.
Vignale, G.
Raimondi, R.
Powiązania:
https://bibliotekanauki.pl/articles/1386604.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.25.Mk
75.70.Tj
85.75.-d
Opis:
In an insulator-metal-insulator junction, inversion-symmetry breaking at the interfaces between the 3D metallic film and the top and bottom insulating layers may give rise to a sizeable (Rashba-like) spin-orbit interaction. In this paper we study the spin Hall and Edelstein effects produced by such an interface interaction through a quasiclassical approach. We find that the spin Hall conductivity has a finite value even if spin-orbit interaction with impurities in the bulk of the metallic film is neglected and disorder is properly taken into account. This is in sharp contrast with the case of a strictly 2D metallic layer, in which case impurity scattering is known to completely suppress Rashba-like contributions to the spin Hall conductivity. The non-vanishing of the latter has a profound influence on the Edelstein effect, which we show to consist of two terms, the first with the standard form valid in an exactly 2D system, and a second arising from the presence of the third dimension.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 457-459
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phonon-Assisted Electronic Transport through Double Quantum Dot System Coupled to Ferromagnetic Leads
Autorzy:
Trocha, P.
Rudziński, W.
Powiązania:
https://bibliotekanauki.pl/articles/1399105.pdf
Data publikacji:
2013-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.25.Mk
73.23.Hk
73.63.Kv
Opis:
Phonon-assisted electronic tunneling is studied through a double quantum dot coupled in parallel to ferromagnetic electrodes. The current-voltage characteristics for the system are derived within the nonequilibrium Green function technique based on equation of motion. It is found that additional phonon-induced resonance peaks appear in the spectral function on both sides of the main resonances corresponding to the quantum dot energy levels. It is shown that the "molecular-like" resonances are reproduced in the phonon side bands in the differential conductance. A significant phonon-induced enhancement of tunnel magnetoresistance as well as tunnel magnetoresistance oscillations are also predicted.
Źródło:
Acta Physica Polonica A; 2013, 124, 5; 843-845
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Andreev Reflection in Transport Through a Quantum Dot Interacting With a Polaron
Autorzy:
Bocian, K.
Rudziński, W.
Powiązania:
https://bibliotekanauki.pl/articles/1202075.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.25.Mk
73.23.Hk
73.63.Kv
74.25.F-
Opis:
Spin-dependent tunneling through a quantum dot coupled to one ferromagnetic and one superconducting electrodes is studied theoretically in the Andreev reflection (AR) regime. Spectral functions for the system are calculated in terms of the nonequilibrium Green function technique. Effects due to interplay between the Coulomb correlations on the dot and the local phonon mode in the context of the AR transmission are analyzed.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 374-375
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermoelectric Effect in Photon-Assisted, Spin-Polarized Tunnelling through a Quantum Dot
Autorzy:
Bocian, K.
Rudziński, W.
Powiązania:
https://bibliotekanauki.pl/articles/1386730.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.25.Mk
73.23.Hk
73.63.Kv
74.25.F-
Opis:
Features of electric and thermal conductance, Seebeck coefficient as well as figure of merit in tunnelling through a single level quantum dot connected to external ferromagnetic leads are investigated theoretically using the equation of motion method within the nonequilibrium Green function technique. The influence of the harmonic ac field on the transport characteristics for the considered system is discussed in detail. In particular, it is shown that the photonic field strongly modulates the Seebeck coefficient, thus resulting in multi-peak structure of figure of merit. Thermoelectric phenomenon in a hybrid junction with the dot attached to two ferromagnetic and one superconducting lead is also discussed.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 484-486
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Temperature Dependence of Spin Hall Effect in k-Cubed Rashba Model
Autorzy:
Krzyżewska, A.
Dyrdał, A.
Berakdar, J.
Powiązania:
https://bibliotekanauki.pl/articles/1030432.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.70.Tj
72.25.-b
72.25.Mk
73.40.-c
Opis:
Within the Matsubara Green function formalism and linear response theory we considered theoretically the temperature dependences of the spin Hall effect for a two-dimensional gas with an isotropic k-cubed form of the Rashba interaction. We utilize a standard model for treating spin-orbit phenomena in p-doped semiconductor heterostructures and also for an electron gas formed at perovskite oxides interfaces.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 558-560
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Andreev Reflection in Transport through a Quantum Dot Coupled to Ferromagnetic and Superconducting Electrodes
Autorzy:
Bocian, K.
Rudziński, W.
Barnaś, J.
Powiązania:
https://bibliotekanauki.pl/articles/1427585.pdf
Data publikacji:
2012-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.25.Mk
73.63.Kv
73.23.Hk
Opis:
Spin-dependent tunneling through a quantum dot coupled to one ferromagnetic and one superconducting electrodes is studied theoretically in the Andreev reflection regime. Electrical conductance is calculated in terms of the nonequilibrium Green function technique. Effects due to the Zeeman splitting of the dot level are analyzed in both linear and nonlinear transport regimes, and are compared with the corresponding effects due to coherent intradot spin rotation.
Źródło:
Acta Physica Polonica A; 2012, 121, 5-6; 1201-1203
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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