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Wyszukujesz frazę "74.45.+c" wg kryterium: Temat


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:
Resonance Tunneling in Ferromagnet-Triplet Superconductors Junctions
Autorzy:
Kowalewski, L.
Wojciechowski, R. J.
Wojtuś, P.
Powiązania:
https://bibliotekanauki.pl/articles/2047330.pdf
Data publikacji:
2007-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.70.Pq
73.40.-c
74.45.+c
Opis:
We discuss the tunneling conductance in a ferromagnet-insulator-triplet superconductor junction. We consider the superconducting order parameters with spin triplet pairing having nodes. The nodal structure of the order parameter has been recently confirmed experimentally in Sr$\text{}_{2}$RuO$\text{}_{4}$. In particular, we study how a mid-gap structure of the tunnelling conductance depends on the phase difference of the pairing potential as well as on the orientation of the interface.
Źródło:
Acta Physica Polonica A; 2007, 111, 5; 683-691
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:
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:
Dynamics of Hotspot Formation in Nanostructured Superconducting Stripes Excited with Single Photons
Autorzy:
Jukna, A.
Kitaygorsky, J.
Pan, D.
Cross, A.
Perlman, A.
Komissarov, I.
Sobolewski, R.
Okunev, O.
Smirnov, K.
Korneev, A.
Chulkova, G.
Milostnaya, I.
Voronov, B.
Gol'tsman, G.
Powiązania:
https://bibliotekanauki.pl/articles/1813380.pdf
Data publikacji:
2008-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.25.Fy
74.25.Sv
74.45.+c
Opis:
Dynamics of a resistive hotspot formation by near-infrared-wavelength single photons in nanowire-type superconducting NbN stripes was investigated. Numerical simulations of ultrafast thermalization of photon-excited nonequilibrium quasiparticles, their multiplication and out-diffusion from a site of the photon absorption demonstrate that 1.55 μm wavelength photons create in an ultrathin, two-dimensional superconducting film a resistive hotspot with the diameter which depends on the photon energy, and the nanowire temperature and biasing conditions. Our hotspot model indicates that under the subcritical current bias of the 2D stripe, the electric field penetrates the superconductor at the hotspot boundary, leading to suppression of the stripe superconducting properties and accelerated development of a voltage transient across the stripe.
Źródło:
Acta Physica Polonica A; 2008, 113, 3; 955-958
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microwave Absorption Study on (Bi,Pb)-Sr-Ca-Cu-O Granular Superconductors
Autorzy:
Jurga, W.
Piekara-Sady, L.
Gazda, M.
Powiązania:
https://bibliotekanauki.pl/articles/1812335.pdf
Data publikacji:
2008-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.70.-b
74.72.-h
74.45.+c
Opis:
(Bi,Pb)-Sr-Ca-Cu-O is considered as a system of 2201, 2212 and 2223 superconductors embedded in the insulating matrix. The size of the grains depends on the time of recrystallization. These types of ceramics exhibit a two-step transition to superconducting state. Because electrical properties depend among other on the Josephson coupling between grains, the magnetically modulated microwave absorption study was undertaken. Magnetically modulated microwave absorption signal was observed to arise just as temperature had been lowered below T₁. The shape of this signal was studied to recognize the second temperature T₂. Some strong oscillations appear on magnetically modulated microwave absorption at lower temperatures, which might be related to local percolation breakdown in superconducting network.
Źródło:
Acta Physica Polonica A; 2008, 114, 1; 253-256
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:
Thermoelectric Transport through a Quantum Dot Coupled to a Normal Metal and BCS Superconductor
Autorzy:
Krawiec, M.
Powiązania:
https://bibliotekanauki.pl/articles/1812283.pdf
Data publikacji:
2008-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.63.Kv
73.23.-b
73.50.Lw
72.15.Qm
74.45.+c
Opis:
We discuss thermoelectric properties of a quantum dot coupled to one normal and one superconducting lead in the presence of the Kondo effect and the Andreev scattering. We will focus on conductance, thermal conductance, thermopower and related quantities like thermoelectric figure of merit which is a direct measure of the usefulness of the system for applications and the Wiedemann-Franz ratio which indicates if the system is in the Fermi liquid state. We will show that the superconductivity strongly modifies the thermal properties of the system. In particular, the thermopower is strongly enhanced near the superconducting transition temperature. Moreover, the Andreev reflections are suppressed due to strong on-dot Coulomb repulsion. The suppression of the Andreev reflections leads to a violation of the Wiedemann-Franz law and to a non-Fermi liquid ground state.
Źródło:
Acta Physica Polonica A; 2008, 114, 1; 115-122
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:
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:
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:
Magnetic Properties of FeSeTe Compound Crystallized from Liquid Phase
Autorzy:
Lewandowski, S.
Berkowski, M.
Tarenkov, V.
D'yachenko, A.
Abal'oshev, A.
Abal'osheva, I.
Gawryluk, D.
Domukhovski, V.
Sidorov, S.
Boichenko, D.
Powiązania:
https://bibliotekanauki.pl/articles/1536749.pdf
Data publikacji:
2010-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.25.Ha
74.45.+c
74.62.Bf
74.70.Xa
75.30.Cr
Opis:
We report on measurements of samples with nominal composition $FeSe_{0.5}Te_{0.5}$, crystallized by the Bridgman method. Magnetic and transport properties of the samples were examined. The measurements confirm the coexistence of ferromagnetism and superconductivity below the superconducting transition temperature. The ferromagnetic contribution to magnetization, estimated at 10%, might be caused by the presence of ferrimagnetic $Fe_7Se_8$, which occupies about 10% of sample volume. From the Andreev spectroscopy we found superconducting energy gap Δ = 2.6 meV at T = 4.2 K, and from magnetization measurements the critical temperature $T_c$ = 15.8 K. The critical current density in magnetic field H = 4 kOe, determined from magnetization measurements, is $j_c$ = (1-2) × 1$0^4$ A/$cm^2$ and weakly depends on magnetic field intensity.
Źródło:
Acta Physica Polonica A; 2010, 118, 2; 289-291
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Physical Properties of "HTSC/Photosemiconductor" Micro- and Nanoplates Based Junctions
Autorzy:
Bunda, V.
Bunda, S.
Vashchuk, F.
Feher, A.
Kováč, J.
Powiązania:
https://bibliotekanauki.pl/articles/1535401.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
85.25.Hv
74.45.+c
74.25.F-
74.55.+v
Opis:
In this paper we report the formation process and electrophysical properties of 'high temperature superconductor $(YBa_2Cu_3O_{7 - x})$/photosemiconductor (BiOCl:Ti)' micro- and nanoplates based junction. The energy band model of ≪HTSC-semiconductor≫ junction is proposed.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 1040-1041
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:
Interference Effects on Double Quantum Dots Coupled Between Metallic and Superconducting Leads
Autorzy:
Barański, J.
Domański, T.
Powiązania:
https://bibliotekanauki.pl/articles/1431289.pdf
Data publikacji:
2012-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.63.Kv
73.23.Hk
74.45.+c
74.50.+r
Opis:
We describe the quantum interference effects in the nanodevice consisting of the double quantum dot coupled to the metallic and superconducting electrodes. In such heterostructures the superconducting properties are spread to the quantum dot due to the proximity effect. We investigate the density of states and anomalous Andreev conductance of the interfacial quantum dot exploring the conditions necessary for appearance of the Fano-type lineshapes. We also consider the electron correlations and discuss an interplay between the Coulomb blockade and the Fano-type interference.
Źródło:
Acta Physica Polonica A; 2012, 121, 4; 812-815
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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