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Wyszukujesz frazę "C23" wg kryterium: Temat


Tytuł:
Temperature Dependence of the Zero-Bias Conductance in the Graphene NIS Junction
Autorzy:
Wysokiński, M.
Powiązania:
https://bibliotekanauki.pl/articles/1374348.pdf
Data publikacji:
2014-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.45.+c
73.23.Ad
Opis:
The temperature dependence of the zero-bias conductance of the graphene-based, ballistic junction composed of the three consecutive regions: normal, with potential barrier ("insulating") and superconducting (NIS), is analyzed within the extended Blonder-Tinkham-Klapwijk approach. Within this approach we have found that oscillatory behavior of the conductance as a function of barrier strength is suppressed by the temperature - the amplitude diminishes with heating up the junction. Moreover, the subtle, although nontrivial feature of the system is reported: the average over the period of the oscillations of the zero-bias conductance for relatively small Fermi level mismatch behaves non-monotonically with the increase of the temperature with the maximum roughly at T/$T_{c}$ ≈ 0.5.
Źródło:
Acta Physica Polonica A; 2014, 126, 4a; A-36-A-39
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Andreev Transport through a Magnetic Molecule Weakly Coupled to Ferromagnetic Leads
Autorzy:
Pawlicki, F.
Weymann, I.
Powiązania:
https://bibliotekanauki.pl/articles/1030385.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.23.-b
74.45.+c
75.50.Xx
Opis:
The Andreev transport through a single molecular magnet coupled to two external ferromagnetic leads and one superconducting electrode is studied theoretically by means of the real-time diagrammatic technique. The calculations are performed by including the sequential tunneling processes between the molecule and ferromagnetic leads, while the coupling to superconductor can be arbitrary. We analyze the dependence of the Andreev current and tunnel magnetoresistance on various intrinsic parameters of the molecule. The superconducting proximity effect results in the formation of molecular Andreev bound states. We show that the transport behavior depends greatly on the type of internal exchange interaction of the molecule, which can lead to corresponding sign changes of the tunnel magnetoresistance of the device.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 594-596
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tunneling through the Quantum Dot Coupled to Incoherent Superconductor
Autorzy:
Donabidowicz, A.
Domański, T.
Powiązania:
https://bibliotekanauki.pl/articles/2047329.pdf
Data publikacji:
2007-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.23.-b
74.20.Fg
74.45.+c
Opis:
We study the equilibrium and non-equilibrium properties of the strongly correlated quantum dot coupled between normal and superconducting leads. The effect of electron pair coherence, Coulomb interactions, and d-wave anisotropy of the order parameter are discussed with a particular account of their influence on a charge tunneling through the quantum dot.
Źródło:
Acta Physica Polonica A; 2007, 111, 5; 671-682
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Interference Effects in Three-Terminal Hybrid Systems with Quantum Dots
Autorzy:
Michałek, G.
Bułka, B.
Powiązania:
https://bibliotekanauki.pl/articles/1403609.pdf
Data publikacji:
2012-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.63.Kv
74.45.+c
73.23.-b
Opis:
Conductance in a three-terminal hybrid system with two quantum dots is analyzed. Our attention is focused on an influence of decoherence on interference effects in the Andreev transport. In particular, we have found that a change of coupling to the third electrode can strongly modify a shape of the Fano-type resonances. This effect is due to activation of nonlocal Andreev reflection (CAR) processes.
Źródło:
Acta Physica Polonica A; 2012, 122, 6; 981-983
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tunneling through the Quantum Dot Coupled between Normal and Superconducting Leads
Autorzy:
Donabidowicz, A.
Domański, T.
Wysokiński, K. I.
Powiązania:
https://bibliotekanauki.pl/articles/2047369.pdf
Data publikacji:
2007-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.23.-b
74.20.Fg
74.45.+c
Opis:
We study the charge tunneling via the quantum dot coupled to normal and superconducting leads, where the superconducting electrode has either an isotropic or anisotropic (of d-wave symmetry) energy gap. We use the single impurity Anderson model and apply the nonequilibrium Green function formalism to determine the differential tunneling conductance. The influence of the proximity effect between the quantum dot and superconductor on the transport properties of the system manifests itself in the Andreev conductance.
Źródło:
Acta Physica Polonica A; 2007, 112, 2; 157-160
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electronic Transport through a Bending Contact
Autorzy:
Schröter, U.
Powiązania:
https://bibliotekanauki.pl/articles/2044664.pdf
Data publikacji:
2006-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.23.-b
74.50.+r
74.45.+c
Opis:
The so-called "break-junction technique" allows us to realize contacts only single-atom in diameter at their thinnest point. Electronic transport through such narrow constrictions shows a quantum mechanical signature which is well described in a transport channel picture. Each individual contact is characterized by an ensemble of channel transmission probabilities. Preferred total conductance values as well as the number of channels, however, turn out to be universal for the material investigated, despite the lack of control of the exact contact geometry.
Źródło:
Acta Physica Polonica A; 2006, 109, 3; 305-310
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Andreev Transport in Double Quantum Dot Cooper Pair Splitters in the Presence of External Magnetic Field
Autorzy:
Trocha, P.
Weymann, I.
Powiązania:
https://bibliotekanauki.pl/articles/1386830.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.23.-b
73.21.La
74.45.+c
Opis:
The effect of external magnetic field on the transport properties of double quantum dots coupled to normal and superconducting leads is studied by means of the real-time diagrammatic technique in the sequential tunneling regime. This device works as a gate-controlled Cooper pair splitter. We focus on the transport regime where the current is blocked due to the spin triplet blockade. It is shown that external magnetic field can modify the Andreev current and differential conductance. In particular, magnetic field can suppress the negative differential conductance associated with the triplet blockade.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 502-504
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Subgap Current through the Strongly Correlated Quantum Dot Hybridized with the Normal and Superconducting Leads
Autorzy:
Domański, T.
Donabidowicz, A.
Powiązania:
https://bibliotekanauki.pl/articles/1810301.pdf
Data publikacji:
2009-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.23.-b
74.20.Fg
74.45.+c
Opis:
We investigate charge tunneling through the strongly correlated quantum dot placed between the metallic and superconducting leads. For small voltages |V| ≤ Δ/e applied across the junction the current is transmitted by the anomalous mechanism of the Andreev reflections. Such transport is sensitive to the strong Coulomb interactions which can be responsible for the charging effect and, at low temperatures, for appearance of the Kondo resonance. We analyze their signatures in the differential Andreev conductance.
Źródło:
Acta Physica Polonica A; 2009, 115, 1; 86-88
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Irreducible green functions method applied to nanoscopic systems
Autorzy:
Górski, G.
Powiązania:
https://bibliotekanauki.pl/articles/1062052.pdf
Data publikacji:
2016-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.63.Kv
73.23.Hk
74.45.+c
Opis:
The equation of motion method for the Green functions is one of the tools used in the analysis of quantum dot system coupled with the metallic and superconducting leads. We investigate modified equation of motion, based on differentiation of double-time temperature dependent Green functions both over the primary time t and secondary time t'. Our equation of motion approach allows us to obtain the Abrikosov-Suhl resonance in the particle-hole symmetric case and also in the asymmetric cases. We will apply the irreducible Green functions technique to analyses of the equation of motion applied to the dot system. This method gives a workable decoupling scheme breaking the infinite set of the Green function equations. We apply this technique to calculate the density of the states and the differential conductance of single-level quantum dot with the Coulomb repulsion attached to one metallic and one superconducting leads (N-QD-SC). Our results are compared with the previous calculations.
Źródło:
Acta Physica Polonica A; 2016, 130, 2; 551-553
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Andreev Reflection and Creation of Spin-Entangled Charge Carriers in Double Barrier Junctions
Autorzy:
Wojciechowski, R.
Kowalewski, L.
Powiązania:
https://bibliotekanauki.pl/articles/1536594.pdf
Data publikacji:
2010-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.45.+c
73.23.Ad
03.65.Ud
Opis:
We discuss spin dependent single particle charge transport as well as the spin pairwise entanglement processes in a double barrier junction. The junction consists of a superconductor connected to two normal or spin-polarized conductors, or semiconductors. Special attention is focused on a non-local process known as a crossed Andreev reflection. The non-local Andreev reflection occurs when an incident electron (hole) from one lead, injected with a subgap energy onto a superconducting layer, transforms into an Andreev hole (electron) in the second lead. At the same time, a Cooper pair is created in the superconductor. Using the Bogolubov-de Gennes equation with appropriate boundary conditions we calculate and discuss probabilities of processes relevant for charge transport through the junction. The dependence of the tunneling charge transport on the strength and orientation of the exchange field in the ferromagnetic electrodes, and on the height of the tunnel barriers as well as on the distance between the electrodes are presented. We discuss briefly the physics of creation and charge transport of spin entangled electron-hole pairs in the junction.
Źródło:
Acta Physica Polonica A; 2010, 118, 2; 249-253
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermoelectric Effect in the Normal Conductor-Superconductor Junction: A BTK Approach
Autorzy:
Wysokiński, M.
Powiązania:
https://bibliotekanauki.pl/articles/1418323.pdf
Data publikacji:
2012-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.45.+c
74.25.fg
73.23.Ad
Opis:
The thermopower of the junction between normal conductor and s-wave superconductor has been investigated. For this purpose we have analyzed in detail a simple generalization of the Blonder-Tinkham-Klapwijk theory by taking into account explicitly an energy dependence of the density of states near the Fermi level. Both linear and nonlinear thermopowers have been calculated for 3D free electron gas, 3D Fermi liquid, and the case with Van Hove singularity in the vicinity of the Fermi level. In the linear regime, for all models, the thermopower as function of temperature has a clear maximum with its position and the value depending strongly on the junction barrier strength. In the nonlinear regime, we have found very large values of the thermopower (up to 8 $k_{B}$/e) and strongly asymmetric behavior with respect to the change of the temperature gradient sign.
Źródło:
Acta Physica Polonica A; 2012, 122, 4; 758-764
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Andreev Spectroscopy in Three-Terminal Hybrid Nanostructure
Autorzy:
Michałek, G.
Bułka, B.
Urbaniak, M.
Domański, T.
Wysokiński, K.
Powiązania:
https://bibliotekanauki.pl/articles/1385343.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.63.Kv
73.23.Hk
74.45.+c
Opis:
We consider a hybrid three-terminal structure consisting of a quantum dot coupled to three leads, two normal and one superconducting. The current flowing between one of the normal and the superconducting electrodes induces voltage in the other normal (floating) electrode. The value of the induced voltage depends on the position of the Andreev levels in the quantum dot and is a measure of the interplay between the electron transfer and the subgap anomalous reflection processes. When the crossed (i.e. non-local) Andreev reflections dominate the induced potential in the normal electrode becomes negative. This situation occurs for the relatively strong coupling to the superconducting electrode and only outside the Coulomb blockade region. Taking the superconducting electrode as the voltage probe one gets additional information on competition of injected carriers.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 293-295
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The In-Gap Charge Current through the Correlated Quantum Dot Hybridized with Superconductor
Autorzy:
Donabidowicz, A.
Domański, T.
Powiązania:
https://bibliotekanauki.pl/articles/1812275.pdf
Data publikacji:
2008-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.23.-b
74.20.Fg
74.45.+c
Opis:
We explore the Andreev tunnelling through the strongly correlated quantum dot embedded between the normal and superconducting electrodes. For a small external voltage |eV| <$∆_s$ the electron arriving from the normal lead can be converted into a pair on the quantum dot and further propagates in the superconducting lead while simultaneously the hole is reflected back to the normal electrode. Conductance of such anomalous current is very sensitive to the particle-hole mixing of the quantum dot spectrum. We analyze the influence of the proximity effect and the Coulomb interactions on the differential Andreev conductance focusing on the extreme limit $∆_s$ → ∞.
Źródło:
Acta Physica Polonica A; 2008, 114, 1; 75-82
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spin Dependent Electron Tunneling in a Ferromagnet Superconductor Ferromagnet Junction
Autorzy:
Kowalewski, L.
Wojciechowski, R.
Powiązania:
https://bibliotekanauki.pl/articles/1810509.pdf
Data publikacji:
2009-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.45.+c
74.50.+r
73.23.Ad
Opis:
The coherent spin polarized transport in ferromagnet/superconductor/ferromagnet double barrier junctions is analyzed. Using the Bogolubov-de Gennes equation with appropriate boundary conditions, we calculate probabilities of spin dependent transport processes in the ferromagnet/superconductor/ferromagnet junction. In particular, we discuss the nonlocal processes such as the crossed Andreev reflection and elastic co-tunneling. These processes contribute to tunneling a current when the distance between the two magnetic electrodes is comparable to the superconducting coherence length. The dependences of the tunneling transport processes on the strength of the exchange field in the ferromagnetic electrodes, and on the height of the tunnel barriers are presented.
Źródło:
Acta Physica Polonica A; 2009, 115, 1; 257-259
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Statistics of Tunneling Events in Three-Terminal Hybrid Devices with Quantum Dot
Autorzy:
Michałek, G.
Bułka, B.
Domański, T.
Wysokiński, K.
Powiązania:
https://bibliotekanauki.pl/articles/1030466.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.45.+c
73.23.Hk
72.70.+m
73.63.Kv
Opis:
We investigate statistics of the tunneling events in the short time limit in terms of the waiting time distribution (WTD), defined as the probability for a delay time between two subsequent transitions of particles, and consider it for a quantum dot (QD) strongly coupled to a superconducting and weakly coupled to two normal electrodes. Our study focuses on the WTD in the subgap transport, when coherent exchange of the Cooper pairs occurs between the QD and the superconductor. The dynamics can be described in terms of a Markovian generalized master equation for the reduced density matrix. We observe coherent oscillations between the Andreev bound states in the correlated jumps, both for the local and non-local WTDs. In addition the analysis of the transient currents give us some insight into dominant relaxation processes in short time scales.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 391-393
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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