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Wyszukujesz frazę "73.23.-b" wg kryterium: Temat


Tytuł:
Quantum-Interference Semiconductor Devices Revisited
Autorzy:
Figielski, T.
Powiązania:
https://bibliotekanauki.pl/articles/2027427.pdf
Data publikacji:
2001-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.23.-b
85.30.De
Opis:
First, a simple semiclassical approach has been applied to the problem of a quantum phase acquired by an electron carrying both the charge and spin, which travels in an electromagnetic field. Basic hypothetical devices whose operation relies on the quantum interference, including spin-related interference, are discussed in the following. Finally, experimental results demonstrating two-beam interference in a planar quantum dot are presented.
Źródło:
Acta Physica Polonica A; 2001, 99, 6; 699-708
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mutual Inductance and Selfinductance in Mesoscopic Systems
Autorzy:
Zipper, E.
Dajka, J.
Szopa, M.
Powiązania:
https://bibliotekanauki.pl/articles/2035547.pdf
Data publikacji:
2002-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.23.Ra
73.23.-b
Opis:
The role played by the magnetostatic interaction in mesoscopic multichannel systems is discussed. We show that the interaction of currents from different channels, when taken in the selfconsistent mean field approximation, leads to selfinductance terms in the Hamiltonian producing an internal magnetic flux. Such multichannel systems can exhibit spontaneous flux or flux expulsion. The dependence of these phenomena on the parameters of the system is discussed.
Źródło:
Acta Physica Polonica A; 2002, 102, 3; 419-428
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theoretical Studies of Quantum Interference in Electronic Transport through Carbon Nanotubes
Autorzy:
Babiaczyk, W. I.
Bułka, B. R.
Powiązania:
https://bibliotekanauki.pl/articles/2035583.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.25.-b
73.23.-b
73.63.Fg
Opis:
We performed studies of coherent electronic transport through a single walled carbon nanotube. In the calculations multiple scattering on the contacts and interference processes were taken into account. Conductance is a composition of contributions from different channels. We studied also spin-dependent transport in the system with ferromagnetic electrodes. The magnetoresistance is large and shows large oscillations, it can be even negative in some cases.
Źródło:
Acta Physica Polonica A; 2002, 102, 4-5; 597-602
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spin Polarized Transport through Quantum Dots: Coulomb Blockade and Kondo Effect
Autorzy:
Barnaś, J.
Świrkowicz, R.
Wilczyński, M.
Weymann, I.
Martinek, J.
Dugaev, V.
Powiązania:
https://bibliotekanauki.pl/articles/2036886.pdf
Data publikacji:
2003-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.25.-b
73.23.Hk
72.15.Qm
Opis:
Spin related effects in electronic transport through quantum dots, coupled via tunneling barriers to two metallic leads, are discussed from the point of view of fundamental physics and possible applications in spin electronics. The effects follow either from long spin relaxation time in the dots or from spin dependent tunneling through the barriers when the external leads are ferromagnetic. In the former case large nonequilibrium spin fluctuations in the dot can be induced by flowing current. These fluctuations modify transport characteristics, particularly the shape of the Coulomb steps. In the latter case electric current depends on magnetic configuration of the system, and tunnel magnetoresistance effect due to magnetization rotation can occur. Transport properties in the weak coupling regime are described perturbatively in the first (sequential) and second (cotunneling) orders. In the strong coupling regime, on the other hand, the equation of motion for nonequilibrium Green functions is used to calculate electric current at low temperatures, where the Kondo peak in conductance is formed in the zero bias regime. In symmetrical systems the Kondo peak is split in the parallel magnetic configuration, whereas no splitting occurs for the antiparallel alignment. Theoretical results are discussed in view of available experimental data.
Źródło:
Acta Physica Polonica A; 2003, 104, 2; 165-177
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electronic Transport through the Double-Dot System
Autorzy:
Świrkowicz, R.
Sztenkiel, D.
Powiązania:
https://bibliotekanauki.pl/articles/2038086.pdf
Data publikacji:
2004-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.20.Hr
72.15.Qm
72.25.-b
73.23.Hk
Opis:
Electron tunnelling through two quantum dots in series is theoretically studied. A limit of intermediate coupling between the dots is considered. The non-equilibrium Green function formalism is used to calculate electric current and mean number of electrons accumulated on the dots. Lesser and retarded Green functions are calculated in the Hartree-Fock approximation with the use of the equation of motion method. Current flowing through the system calculated in dependency on gate voltages shows two resonant peaks, each peak with two additional shoulders. I-V characteristics and differential conductance in a resonance and out of resonance cases are calculated and discussed.
Źródło:
Acta Physica Polonica A; 2004, 105, 6; 523-528
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nonequilibrium Kondo Effect in a Single-Channel Quantum Dot Asymmetrically Coupled to Two Ferromagnetic Reservoirs
Autorzy:
Świrkowicz, R.
Wilczyński, M.
Barnaś, J.
Powiązania:
https://bibliotekanauki.pl/articles/2037118.pdf
Data publikacji:
2004
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.20.Hr
72.15.Qm
72.25.-b
73.23.Hk
Opis:
Nonequilibrium Kondo effect in a quantum dot asymmetrically coupled to two ferromagnetic metallic leads is analyzed theoretically. The nonequilibrium Green function technique is used to calculate density of states and electric current. The lesser and retarded (advanced) Green functions are calculated by the equation of motion method within a consistent approximation scheme. The case where one electrode is half-metallic is analyzed numerically in details.
Źródło:
Acta Physica Polonica A; 2004, 105, 1-2; 149-154
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hartree-Fock Simulation of Persistent Current in Rings with Single Scatterer
Autorzy:
Németh, R.
Moško, M.
Powiązania:
https://bibliotekanauki.pl/articles/2044507.pdf
Data publikacji:
2005-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.23.-b
73.61.Ey
Opis:
Using the self-consistent Hartree-Fock approximation for spinless electrons at zero temperature, we calculate the persistent current of the interacting electron gas in a one-dimensional ring containing a single δ barrier. Our results agree with correlated models like the Luttinger liquid model and lattice model with nearest-neighbor interaction. The persistent current is a sine-like function of magnetic flux. It decays with the ring length (L) faster than L$\text{}^{-1}$ and eventually like L$\text{}^{-α-1}$, where α>0 is universal.
Źródło:
Acta Physica Polonica A; 2005, 108, 5; 795-801
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spin Polarized Transport through the Double-Dot System
Autorzy:
Sztenkiel, D.
Świrkowicz, R.
Powiązania:
https://bibliotekanauki.pl/articles/2044544.pdf
Data publikacji:
2005-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.20.Hr
72.15.Qm
72.25.-b
73.23.Hk
Opis:
Spin-dependent electron transport through two quantum dots in series attached to ferromagnetic electrodes is analyzed within the framework of the non-equilibrium Green function formalism. Regime of a weak coupling between the dots is investigated. I-V characteristics and tunnel magnetoresistance are calculated and discussed in detail.
Źródło:
Acta Physica Polonica A; 2005, 108, 5; 885-890
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Terahertz Generation and Detection by Plasma Waves in Nanometer Gate High Electron Mobility Transistors
Autorzy:
Knap, W.
Łusakowski, J.
Teppe, F.
Dyakonova, N.
Meziani, Y.
Powiązania:
https://bibliotekanauki.pl/articles/2041635.pdf
Data publikacji:
2005-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.21.-b
73.23.-b
Opis:
The high electron mobility transistors can act as a resonator cavity for the plasma waves that can reach THz frequencies for a nanometer size devices. As was predicted by Dyakonov and Shur in 1993, the steady state of the current flow in a gated 2D electron gas can become unstable leading to the emission of an electromagnetic radiation at the plasma wave frequencies. The theory predicted also that the plasma waves can be used for resonant detection of THz electromagnetic radiation. In the present paper we review our recent experiments on THz emission and detection performed on high electron mobility transistors based on different semiconductor structures: InGaAs/GaAlAs, GaAs/GaAlAs, and Si.
Źródło:
Acta Physica Polonica A; 2005, 107, 1; 82-91
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tunneling of Interacting Fermions in 1D Systems
Autorzy:
Gendiar, A.
Moško, M.
Vagner, P.
Németh, R.
Powiązania:
https://bibliotekanauki.pl/articles/2043712.pdf
Data publikacji:
2005-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.23.-b
73.61.Ey
Opis:
Using the self-consistent Hartree-Fock approximation for spinless electrons at zero temperature, we study tunneling of the interacting electron gas through a single δ barrier in a finite one-dimensional wire connected to contacts. Our results exhibit features known from correlated many-body models. In particular, the conductance decays with the wire length as ∝ L$\text{}^{-2α}$, where the powerα is universal. We also show that a similar result for a wire conductance can be extracted from the persistent current (I) through theδ barrier in a one-dimensional ring, where it is known that I∝ L$\text{}^{-1-α}$.
Źródło:
Acta Physica Polonica A; 2005, 108, 4; 661-667
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Different Quantization Mechanisms in Single-Electron Pumps Driven by Surface Acoustic Waves
Autorzy:
Utko, P.
Gloos, K.
Bindslev Hansen, J.
Sørensen, C.
Lindelof, P.
Powiązania:
https://bibliotekanauki.pl/articles/2047039.pdf
Data publikacji:
2006-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.23.-b
72.50.+b
73.21.La
Opis:
We have studied the acoustoelectric current in single-electron pumps driven by surface acoustic waves. We have found that in certain parameter ranges two different sets of quantized steps dominate the acoustoelectric current versus gate-voltage characteristics. In some cases, both types of quantized steps appear simultaneously though at different current values, as if they were superposed on each other. This could indicate two independent quantization mechanisms for the acoustoelectric current.
Źródło:
Acta Physica Polonica A; 2006, 110, 3; 403-408
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electron Transport through Double Quantum Dots with Interdot Coulomb Repulsion
Autorzy:
Sztenkiel, D.
Świrkowicz, R.
Powiązania:
https://bibliotekanauki.pl/articles/2047016.pdf
Data publikacji:
2006-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.23.-b
73.21.La
73.23.Hk
Opis:
Electron transport through a system of two quantum dots connected in series is studied theoretically with the use of non-equilibrium Green function formalism based on the equation of motion method. Each dot is described by the one-level Anderson Hamiltonian and interdot Coulomb interactions in the form of the Hubbard-like term are taken into account. The electric current and occupation numbers are calculated with the use of two different approaches. The results of the methods are compared and discussed in detail. Strong asymmetry of I-V characteristics with respect to bias voltage reversal are obtained when energy levels of the dots are not aligned.
Źródło:
Acta Physica Polonica A; 2006, 110, 3; 389-394
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:
Coherent Transport through Systems of Coupled Quantum Dots
Autorzy:
Trocha, P.
Barnaś, J.
Powiązania:
https://bibliotekanauki.pl/articles/2047730.pdf
Data publikacji:
2007-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.23.-b
73.21.La
73.23.Hk
Opis:
Spin-dependent electronic transport through two coupled single-level quantum dots attached to ferromagnetic leads with parallel and antiparallel magnetizations is analyzed theoretically. The intra-dot Coulomb correlation is taken into account, while the inter-dot Coulomb repulsion is omitted. Conductance and tunnel magnetoresistance associated with magnetization rotation are calculated by the nonequilibrium Green function technique. The relevant Green functions are derived by the equation of motion method in the Hartree-Fock approximation. The dot occupation numbers and the Green functions are calculated self-consistently. The interference effects in electronic transport through quantum dots are analyzed in two different configurations. It is shown that the Fano resonance in conductance can be observed even for vanishing inter-dot hopping parameter t. The interplay of the interference effects and the Coulomb interactions in quantum dots is also analyzed.
Źródło:
Acta Physica Polonica A; 2007, 112, 2; 473-480
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electron Transport through Double Quantum Dot System with Inter-Dot Coulomb Interaction
Autorzy:
Sztenkiel, D.
Świrkowicz, R.
Powiązania:
https://bibliotekanauki.pl/articles/2047295.pdf
Data publikacji:
2007-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.23.-b
73.21.La
73.23.Hk
Opis:
A theoretical approach to a problem of electron transport through double quantum dot systems based on non-equilibrium Green function formalism using equation of motion method is presented. I-V characteristics and differential conductance are calculated and discussed in detail in the intermediate regime with tunneling rate between the quantum dots comparable to coupling constants with external electrodes. Effects of inter-dot Coulomb correlations are studied for various values of interaction parameter U. It is shown that the interaction influences transport properties in a pronounced way and apart from the simple Coulomb blockade additional effects can be obtained. When energy levels of two quantum dots are not aligned, the asymmetry in conductance characteristics is closely related to a voltage dependence of population numbers in both quantum dots. For a one bias polarization electrons are well localized in quantum dots in a low voltage region, whereas for the opposite one they are partly delocalized.
Źródło:
Acta Physica Polonica A; 2007, 111, 3; 361-372
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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