Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

English (EN)·Polski (PL)·Yкраїнський (UK)
Przejdź do strony domowej biblioteki Centralna Biblioteka Wojskowa Link otwiera się w nowym oknie Logo biblioteki Prolib Integro - strona głównaCentralna Biblioteka Wojskowa

Wyszukujesz frazę "73.63.KV" wg kryterium: Temat

  Lista filtrów
Wyrównaj
Wyświetlanie 1-50 z 60
Tytuł:
Quasistationary Electron States for CdTe/ZnTe/CdTe Open Spherical Quantum Dots
Autorzy:
Stojanović, D.
Kostić, R.
Powiązania:
https://bibliotekanauki.pl/articles/1537875.pdf
Data publikacji:
2010-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.63.Kv
73.22
Opis:
The energy spectra of an electron in open spherical quantum dot (QD) within the effective mass approximation (EMA) and rectangular potential model is presented. Energy structure of quantum dots is important because of their possible applications in electronic and optoelectronic devices. For proper description and interpretation of tunneling processes knowledge of resonant states of quantum dots is necessary. Energy values depend on parameter like size of system and spatial composition. The lifetimes of the quasistationary states are computed within the framework of the scattering S-matrix method. It is shown how core radius and barrier thickness for the CdTe/ZnTe/CdTe example influence electron states and their lifetimes.
Źródło:
Acta Physica Polonica A; 2010, 117, 5; 768-771
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of retrapping on thermoluminescence peak intensities of small amorphous silicon quantum dots
Autorzy:
Debelo, N.
Dejene, F.
Mal'nev, V.
Senbeta, T.
Mesfin, B.
Roro, K.
Powiązania:
https://bibliotekanauki.pl/articles/1070477.pdf
Data publikacji:
2016-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.21.La
73.63.Kv
Opis:
The effect of retrapping on thermoluminescence intensity peak corresponding to each trap of small amorphous silicon quantum dots in three traps - one recombination center model is investigated. For first order kinetics, where there is no effect of retrapping, the thermoluminescence intensity clearly depends on the level of the trap beneath the edge of the conduction band. This energy difference between the edge of the conduction band and the level of the trap is called trap depth (activation energy). The shallowest trap gives the highest thermoluminescence intensity peak for first order kinetics. However, it was clearly observed that for second order and a case beyond second order kinetics, the thermoluminescence intensity peak corresponding to each trap does not depend on the trap depth. In this case, the retrapping probability coefficients are taken into account and most electrons which are detrapped from the shallow trap(s) will be retrapped to the deeper trap(s) resulting in fewer electrons taking part in the recombination process. This significantly reduces the thermoluminescence intensity peaks of the shallower trap(s). It was observed that the deepest trap, with very high concentration of electrons due to the retrapping phenomenon, gives the highest thermoluminescence intensity. In addition, the variation of concentration of electrons in each trap and the intensity of the thermoluminescence are presented. Though we considered the model of three traps and one recombination center, this phenomenon is true for any multiple traps.
Źródło:
Acta Physica Polonica A; 2016, 129, 3; 362-366
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Energy Band and Absorption Coefficient of Quantum Dots in a Well Structure
Autorzy:
Zhang, P.
Lu, X.
Zhang, C.
Yao, J.
Powiązania:
https://bibliotekanauki.pl/articles/1419887.pdf
Data publikacji:
2012-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.21.La
73.63.Kv
Opis:
Building on the effective-mass envelope function theory, this paper focuses on the study of the energy band and the absorption coefficient of $InAs//In_{x}Ga_{1 - x}As$ quantum dots in a well (DWELL) structure. In contrast to $InAs//In_{0.15}Ga_{0.85}As$ quantum DWELL, the $InAs//In_{0.2}Ga_{0.8}As$ quantum DWELL has lower ground states. With the thickness of $In_{0.15}Ga_{0.85}As$ layer changing from 7 nm to 9 nm and $In_{0.2}Ga_{0.8}As$ layer changing from 9 nm to 12 nm, the calculation shows that their absorption coefficient spectra takes a red shift in the long-wave infrared and far-infrared ranges, respectively. Moreover, when the thickness of the $In_{x}Ga_{1 - x}As$ layer is defined as 9 nm, the absorption coefficient spectra of $InAs//In_{0.2}Ga_{0.8}As$ DWELL shows a obvious red shift comparing with that of $InAs//In_{0.15}Ga_{0.85}As$ DWELL.
Źródło:
Acta Physica Polonica A; 2012, 122, 1; 197-201
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Level Occupancy Anomalies in a Double QD System
Autorzy:
Stefański, P.
Powiązania:
https://bibliotekanauki.pl/articles/1810305.pdf
Data publikacji:
2009-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.63.Kv
73.23.Hk
Opis:
A double quantum dot system is considered in the presence of the electron intra-Coulomb U interactions within the dots and inter-Coulomb $U_{12}$ interactions between them. We show that both for spinless and spinfull electrons the dots occupancy anomalies are encountered and caused by electron correlations. This non-monotonic behavior strongly deviates from usual level filling at the Coulomb blockade. For spinfull electrons the inter-dot interaction modifies also on-site electron correlations.
Źródło:
Acta Physica Polonica A; 2009, 115, 1; 92-94
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phonon-Assisted Excitation Transfer in Quantum Dot Molecules
Autorzy:
Rozbicki, E.
Machnikowski, P.
Powiązania:
https://bibliotekanauki.pl/articles/2047376.pdf
Data publikacji:
2007-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
63.20.Kr
73.63.Kv
Opis:
We derive a quantum-kinetic description of phonon-assisted Förster transfer between two coupled quantum dots (a quantum dot molecule). We show that the exciton state decays to the ground state of the quantum dot molecule via a combination of the Rabi rotation and exponential decay. For moderately spaced dots this process takes place on a picosecond timescale.
Źródło:
Acta Physica Polonica A; 2007, 112, 2; 197-202
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The calculation for strain distributions and electronic structure of InAs/GaAs quantum dots based on the eight-band k·p theory
Autorzy:
Shu, Changgan
Liu, Yumin
Powiązania:
https://bibliotekanauki.pl/articles/1070532.pdf
Data publikacji:
2016-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.21.La
73.63.Kv
Opis:
In order to analyze the strain distribution of InAs/GaAs quantum dot in a pyramidal geometry, the traditional calculation method is based on the single band envelope approximation with the modified band edge from the eight band k·p theory. In this paper, we use the eight band k·p Hamiltonian to calculate, and the piezoelectric effects and the electronic structure are also discussed subsequently. To this end, some necessarily derived formulae in calculations about using the finite element calculation software COMSOL are presented in this paper. The results show the details about strain distributions, piezoelectric effects and electronic structure of an InAs/GaAs pyramidal quantum dot, verify the feasibility and efficiency of the calculation method.
Źródło:
Acta Physica Polonica A; 2016, 129, 3; 371-377
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electronic Transport through a Quantum Dot Coupled to Non-Collinear Ferromagnetic Electrodes: The Kondo Regime
Autorzy:
Świrkowicz, R.
Wilczyński, M.
Wawrzyniak, M.
Barnaś, J.
Powiązania:
https://bibliotekanauki.pl/articles/1813915.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.23.Hk
73.63.Kv
Opis:
Linear and non-linear conductance of quantum dots attached to magnetic leads is considered theoretically in the Kondo regime. The considerations are based on the non-equilibrium Green function formalism and the relevant equation of motion method. Splitting of the Kondo anomaly due to coupling of the dot to ferromagnetic electrodes, and its dependence on magnetic configuration of the system and on the lead's spin polarization is studied numerically.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 565-568
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quantum States of Self-Assembled InAs Dots Probed by Magneto-Tunneling Spectroscopy
Autorzy:
Patanè, A.
Eaves, L.
Main, P. C.
Levin, A.
Zambrano, M. L.
Henini, M.
Vdovin, E. E.
Dubrovskii, Y. V.
Hill, G.
Powiązania:
https://bibliotekanauki.pl/articles/2027456.pdf
Data publikacji:
2001-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.63.-b
73.63.Kv
73.43.Jn
Opis:
We present an experimental study of the electron wave function in InAs/GaAs self-assembled quantum dots. Magneto-tunneling spectroscopy is employed as a non-invasive probe to produce two-dimensional images of the probability density of an electron confined in a quantum dot. The images reveal the elliptical symmetry of the ground state and the characteristic lobes of the higher energy states of the dots.
Źródło:
Acta Physica Polonica A; 2001, 100, 2; 165-173
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phonon-Assisted Tunneling of an Electron in a Strained Self-Assembled Quantum Dot Molecule
Autorzy:
Pochwała, M.
Machnikowski, P.
Powiązania:
https://bibliotekanauki.pl/articles/1811973.pdf
Data publikacji:
2008-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.21.La
73.63.Kv
63.20.kd
Opis:
We calculate phonon-assisted relaxation rates in a self-assembled quantum dot molecule. The calculation is based on wave functions obtained within an envelope function approach, including strain effects. The single-phonon relaxation is shown to be efficient for separations between the dots around 10 nm when, in addition, the dots are brought close to resonance.
Źródło:
Acta Physica Polonica A; 2008, 114, 5; 1285-1291
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Threshold Effects in Three-Terminal Hybrid Systems
Autorzy:
Michałek, G.
Powiązania:
https://bibliotekanauki.pl/articles/1201870.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.63.Kv
73.63.-b
74.45.+c
Opis:
In the paper we study transport in the three terminal hybrid devices with quantum dot. Our attention is focused on the conductance threshold effects (so called Wigner singularities) caused by the back action from the side-wire. In particular we study influence of the direct electron transfer (ET) and crossed Andreev reflection (CAR) processes on the conductance caused by the direct Andreev reflection (DAR) processes.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 224-225
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electron States, Phonon-Assisted Relaxation and Tunneling in Self-Assembled Quantum Dot Molecules in an Electric Field
Autorzy:
Gawarecki, K.
Machnikowski, P.
Powiązania:
https://bibliotekanauki.pl/articles/2048065.pdf
Data publikacji:
2011-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.21.La
73.63.Kv
63.20.kd
Opis:
We present a theoretical analysis of the phonon-assisted relaxation in a system composed of two self-assembled vertically stacked quantum dots. We construct realistic model, which takes into account the geometry and strain distribution in the system. We calculate phonon-assisted relaxation rates between the two lowest states (in one- and two-electron cases). The relaxation rates and energy levels are studied as a function of external (axial) electric field and geometry of the structure (dot sizes). We show that the relaxation times can be as low as 1 ps but efficient relaxation occurs only for very finely tuned dots.
Źródło:
Acta Physica Polonica A; 2011, 119, 5; 637-639
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermoelectric Transport through the Double Quantum Dot in the Sequential Tunneling Regime
Autorzy:
Szukiewicz, B.
Wysokiński, K.
Powiązania:
https://bibliotekanauki.pl/articles/1195458.pdf
Data publikacji:
2014-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.23.-b
73.63.Kv
73.23.Hk
Opis:
The charge and spin thermoelectric transport in the system composed of a central molecule in contact with two normal electrodes in an external magnetic field of the Zeeman type have been studied. Such system can support pure spin current for applications in spintronics. By appropriate gate tuning of each of the dots it is possible to electrically control the direction of the spin current or tune the device operating as a thermoelectric generator to optimal performance.It has been shown that the device is poor energy converter in the parameter region where its thermoelectric figure of merit attains very large values.
Źródło:
Acta Physica Polonica A; 2014, 126, 5; 1159-1162
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Novel Approach for Energy Spectrum Probing in Semiconducting Quantum Dots
Autorzy:
Zdrojek, M.
Wąsik, M.
Esplandiu, M.
Bachtold, A.
Powiązania:
https://bibliotekanauki.pl/articles/1419526.pdf
Data publikacji:
2012-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.22.Dj
73.23.Hk
73.63.Kv
Opis:
A new technique has been used to probe the electronic properties of quantum dots. Here we discuss the case of semiconducting CdSe dots. This technique allows us to fill (or empty) semiconducting quantum dot with many electrons. The detection scheme is based on an original approach where the investigated particle is attached to only one electrode, a carbon nanotube. The conductance of the nanotube is measured as a function of a gate voltage $(V_{g}),$ which allows the detection of individual electrons transferred onto the quantum dot. For certain range of $V_{g}$ we noticed no electron transfer which is attributed to the energy gap of the CdSe quantum dot. Our study shows that single-electron detection with carbon nanotube transistor represents a new strategy to study the separation between the electronic discrete energy levels of the semiconducting quantum dot.
Źródło:
Acta Physica Polonica A; 2012, 122, 2; 321-323
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cross-Correlations and Charge Pumping in Shot Noise οf Coupled Quantum Dot System
Autorzy:
Michałek, G.
Bułka, B.
Powiązania:
https://bibliotekanauki.pl/articles/1791333.pdf
Data publikacji:
2009-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.23.Hk
73.63.Kv
73.50.Td
Opis:
We analyze current auto- and cross-correlations in the system of two capacitively coupled large quantum dots. Our attention is focused on the strong inter-dot coupling when an electron transfer through one of the quantum dots induces charge pumping through the second quantum dot. We show individual contributions to shot noise from various tunneling processes in the charge space.
Źródło:
Acta Physica Polonica A; 2009, 116, 5; 879-881
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Enhancement of Current Auto- and Cross-Correlations in Double Quantum Dots
Autorzy:
Michałek, G.
Bułka, B.
Powiązania:
https://bibliotekanauki.pl/articles/1810396.pdf
Data publikacji:
2009-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.23.Hk
73.63.Kv
73.50.Td
Opis:
Studies of an enhancement of current shot noises are presented for a device of two large quantum dots coupled capacitively. We analyze current-current correlation functions, and show that a dynamical Coulomb blockade is responsible for an enhancement of the Fano factors. This process can lead also to an electron bunching and positive current cross-correlations. Our theoretical results are discussed in light of recent shot noise experiments.
Źródło:
Acta Physica Polonica A; 2009, 115, 1; 117-119
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phonon Effects on the Weak Measurement of Charge States in Quantum Dots with a Quantum Point Contact
Autorzy:
Marcinowski, Ł.
Krzyżosiak, M.
Machnikowski, P.
Buczko, R.
Mostowski, J.
Roszak, K.
Powiązania:
https://bibliotekanauki.pl/articles/2048072.pdf
Data publikacji:
2011-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.63.Kv
03.65.Ta
63.20.kd
Opis:
We study theoretically the process of a weak measurement of charge states in a double quantum dot performed by coupling to a quantum point contact. We focus on the interplay of the measurement process with phonon-induced dephasing of delocalized superpositions of electron states and compare the time scales relevant for the dynamics of the open system and for the measurement process: the decoherence rate, the localization rate of the state conditioned on the measurement outcome and the time scale on which information on the system state is gained in the process of the measurement.
Źródło:
Acta Physica Polonica A; 2011, 119, 5; 640-643
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Magnetic Zigzag Edges in Graphene-like Nanoribbons on the Thermoelectric Power Factor
Autorzy:
Krompiewski, S.
Cuniberti, G.
Powiązania:
https://bibliotekanauki.pl/articles/1030504.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.63.Kv
72.25.-b
73.50.Lw
Opis:
This study shows that magnetic edge states of graphene-like nanoribbons enhance effectively the thermoelectric performance. This is due to the antiparallel alignment of magnetic moments on opposite zigzag edges and the confinement effect, which jointly lead to the appearance of a gap in the electronic energy spectrum. Consequently, the Seebeck coefficient as well as the thermoelectric power factor get strongly enhanced (with respect to other alignment cases) at room temperature and energies not far away from the charge neutrality point. Moreover the corresponding figure of merit (ZT) is also improved as a result of the reduced electronic thermal conductance.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 535-537
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Waiting Time Correlations in Transport through Two Coupled Quantum Dots
Autorzy:
Ptaszyński, K.
Powiązania:
https://bibliotekanauki.pl/articles/1191206.pdf
Data publikacji:
2016-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.70.+m
73.23.Hk
73.63.Kv
Opis:
Waiting times between subsequent tunneling events in the double quantum dot system are shown to be correlated. The magnitude and the sign of the cross-correlation depend on the degree and the character of modulation of tunneling rates in the one dot due to the interaction with the charge state of the other, as well as on the relation between different time scales of the system dynamics.
Źródło:
Acta Physica Polonica A; 2016, 130, 5; 1233-1235
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 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
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:
The Magnetic Field Effects on Spin Polarization of T-Shaped Double Quantum Dots Coupled to Ferromagnetic Leads
Autorzy:
Wójcik, K.
Weymann, I.
Powiązania:
https://bibliotekanauki.pl/articles/1384834.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.23.Hk
73.63.Kv
85.75.-d
Opis:
We analyze the spin-dependent conductance and spin polarization of a double quantum dot in a T-shape configuration coupled to ferromagnetic leads in the presence of external magnetic field. The calculations are performed with the aid of the numerical renormalization group method. We show that in the antiparallel configuration, finite magnetic field can give rise to the full spin polarization of the current, which can be controlled by tuning the dots' levels. On the other hand, for parallel configuration enhanced spin polarization can be generated by an exchange field due to the presence of ferromagnetic leads and can be also tuned by changing level position or external magnetic field. The magnetic field can be thus used to improve the spin-resolved properties of the system.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 222-224
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Noise Enhancement due to Telegraphic Switching in a Two-Level Quantum Dot Coupled to Spin-Polarized Leads
Autorzy:
Ptaszyński, K.
Powiązania:
https://bibliotekanauki.pl/articles/1030411.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.70.+m
73.23.Hk
73.63.Kv
Opis:
Current fluctuations in a two-level quantum dot coupled to the spin-polarized leads are studied by means of the Markovian master equation. It is shown, that transitions between spin configurations of the system cause switching between different current channels, which generates the super-Poissonian noise enhancement and the correlation between subsequent waiting times separating the successive tunneling events.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 526-528
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamics of a Charge Qubit Encoded in a Double Quantum Dot
Autorzy:
Łuczak, J.
Bułka, B.
Powiązania:
https://bibliotekanauki.pl/articles/1030456.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
03.67.Lx
73.63.Kv
73.23.Ra
Opis:
We study the short time dynamics of a charge qubit encoded in two coherently coupled quantum dots connected to external electrodes. In the regime of sequential tunneling the waiting time distribution is used to investigate in details statistics of the tunneling events and their correlations. We show that the coherent rotation of the qubit state on the Bloch sphere can be seen in tunneling events when an electron is injected and leave the system. Decoherence, relaxation of the qubit state as well as leakage processes are studied by means of transient currents.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 748-750
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:
Alternative Equation of Motion Approach to the Single-Impurity Anderson Model
Autorzy:
Górski, G.
Mizia, J.
Kucab, K.
Powiązania:
https://bibliotekanauki.pl/articles/1374793.pdf
Data publikacji:
2014-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.10.Fd
73.20.Fz
73.63.Kv
Opis:
Solving the single-impurity Anderson model is a basic problem of solid state physics. The single-impurity Anderson model is very important, at present it is also used for systems with quantum impurities, e.g. semiconductor quantum dots and molecular transistors. Its main application is in the scheme of dynamical mean field theory describing strong correlation electron systems. To solve the single-impurity Anderson model problem we use the equation of motion Green function approach. In this report we present the novel equation of motion approximation in which we differentiate the Green function over both time variables. This differs from the commonly used equation of motion solution by Appelbaum, Penn and Lacroix where the authors take time derivative only over primary time variable. After extending calculations to higher order Green functions we find the new approximate dynamical solution of single-impurity Anderson model. The results are compared with the solutions to the single-impurity Anderson model problem at intermediate Coulomb repulsion U such as the modified iterative perturbation theory. Our approach is suitable for describing quantum dots.
Źródło:
Acta Physica Polonica A; 2014, 126, 4a; A-97-A-99
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:
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:
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:
An Improved 2.5 GHz Electron Pump: Single-Electron Transport through Shallow-Etched Point Contacts Driven by Surface Acoustic Waves
Autorzy:
Utko, P.
Gloos, K.
Hansen, J. B.
Lindelof, P. E.
Powiązania:
https://bibliotekanauki.pl/articles/2035753.pdf
Data publikacji:
2003-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.63.Kv
72.50.+b
06.20.Jr
Opis:
We present an experimental study of a 2.5 GHz electron pump based on the quantized acoustoelectric current driven by surface acoustic waves through a shallow-etched point contact in a GaAs/AlGaAs heterostructure. At low temperatures and with an additional counter-propagating surface acoustic waves beam, up to n=20 current plateaus at I=nef could be resolved, where n is an integer, e the electron charge, and f the surface acoustic waves frequency. In the best case the accuracy of the first plateau at 0.40 nA was estimated to beΔ I/I=±25 ppm over 0.25 mV in gate voltage, which is better than previous results.
Źródło:
Acta Physica Polonica A; 2003, 103, 6; 533-538
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Introduction to the Physics of Quantum Dots
Autorzy:
Kardynal, B.
Powiązania:
https://bibliotekanauki.pl/articles/2027478.pdf
Data publikacji:
2001-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.63.Kv
78.67.Lt
81.07.Ta
Opis:
Quantum dots contain only a few well-defined energy levels for electron and/or holes as a result of the confinement of charge in all three spatial dimensions. Here, we describe both the application of photoluminescence spectroscopy and transport measurements to the characterisation of quantum dots and the novel phenomena that they exhibit. These include the Coulomb blockade, single electron tunnelling and single photon detection. The impact of quantum dots on future electronics and directions for future research, such as in quantum computing and cryptography, are addressed.
Źródło:
Acta Physica Polonica A; 2001, 100, 3; 275-286
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transport Phenomena in Two-Dimensional Structures with Quantum Dots
Autorzy:
Požela, J.
Powiązania:
https://bibliotekanauki.pl/articles/2041644.pdf
Data publikacji:
2005-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.63.Hs
73.63.Kv
85.35.Be
85.30.Tv
Opis:
A model that explains the unusual characteristics of the AlGaAs/GaAs modulation-doped field-effect transistor (MODFET) with InAs quantum dots incorporated in the GaAs channel is presented. It is shown that the negative charge of electrons confined in quantum dots decreases the threshold gate-drain voltage at which the channel is fully depleted. This provides an impact ionization of quantum dots at a low drain voltage. Because of the quantum dot ionization, the quantum dot MODFET transconductance becomes large and negative. The increased transconductance, due to the additional doping of the GaAs and InAs channels by impurities, exceeds 10$\text{}^{3}$ mS/mm. It is shown that the insertion of InAs quantum well with quantum dots into the GaAs quantum well increases the electron maximum drift velocity up to 10$\text{}^{8}$ cm/s, and consequently, quantum dot MODFET current gain cut-off frequency up to few hundred gigahertz.
Źródło:
Acta Physica Polonica A; 2005, 107, 1; 118-127
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Correlation Effects and Spin Dependent Transport in Carbon Nanostructures
Autorzy:
Lipiński, S.
Krychowski, D.
Powiązania:
https://bibliotekanauki.pl/articles/1201833.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.10.Fk
73.63.Fg
73.63.Kv
85.75.-d
Opis:
The impact of symmetry breaking perturbations on the spin dependent transport through carbon nanotube quantum dots in the Kondo regime is discussed. The proposals of spin filter, spin valve and spin battery are presented.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 190-193
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermoelectric Effects in Carbon Nanotube Quantum Dot in the Kondo Regime
Autorzy:
Krychowski, D.
Lipiński, S.
Powiązania:
https://bibliotekanauki.pl/articles/1813488.pdf
Data publikacji:
2008-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.63.KV
72.10.Fk
73.63.-b
65.80.+n
Opis:
Thermoelectric effects in a carbon nanotube quantum dot in the Kondo regime are studied by the equation of motion method. The thermopower is highly sensitive to the structure of the spectral density near the Fermi edge. For temperatures close to the Kondo temperature the thermopower approaches a local minimum, which becomes sharper for orbital energies closer to the Fermi level. For higher temperatures the tjermopower increases, but in the temperature range corresponding to charging energy it again drops and achieves significant negative values. We examine the consequences of symmetry breaking of spin-orbital SU(4) system on thermopower.
Źródło:
Acta Physica Polonica A; 2008, 113, 2; 645-649
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on Fluorescence Characteristic of a Complex Probe οf CdSe Quantum Dots Coupling with Thiazole Orange
Autorzy:
Fei, X.
Jia, G.
Wang, J.
Gu, Y.
Powiązania:
https://bibliotekanauki.pl/articles/1537765.pdf
Data publikacji:
2010-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.63.Kv
78.55.-m
78.67.-n
Opis:
CdSe quantum dots were synthesized using thioglycolic acid as stabilizer in aqueous solution under $N_{2}$. The UV-vis spectrometry and fluorescence spectra indicate that the bimodal quantum dots were formed and the optical band gaps are about 650 nm and 750 nm, respectively. The quantum dots coated with TO were prepared in room temperature, and the fluorescence characteristic was studied. The result showed that the peak shift of quantum dots fluorescence spectra can mainly be due to the change of the capping layer, resulting in the confinement energy change. This is vital for the investigating on of the forming process and mechanisms of the combination of thiazole orange dye and quantum dots.
Źródło:
Acta Physica Polonica A; 2010, 117, 6; 949-952
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spin-Dependent Transient Effects in Electron Transport in the Quantum Dot System
Autorzy:
Parafiniuk, P.
Taranko, R.
Powiązania:
https://bibliotekanauki.pl/articles/1791296.pdf
Data publikacji:
2009-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.25.-b
73.63.Kv
85.75.-d
Opis:
We study the effects of the Coulomb interaction U between the electrons of opposite spins localized in the quantum dot on the time-dependent electron transport through the quantum dot coupled with two non-magnetic leads. We calculate the transient spin-dependent current generated by a pulsed bias voltage applied across the quantum dot system via the equation of motion method for appropriate correlation functions. The influence of the Coulomb interaction on the quantum coherent oscillations and beats of the current, spin current and current polarization ratio is studied. Our results indicate that the coherent beats in both the total and spin currents observed in the case of vanishing Coulomb interaction are strongly suppressed by non-zero Coulomb interaction. We also show that in the case of the pulsed bias almost fully polarized current occurs in some time windows for non-vanishing Coulomb interaction contrary to almost pure charge or spin current at vanishing U.
Źródło:
Acta Physica Polonica A; 2009, 116, 5; 844-846
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photoelectrical Properties of 1.3μm Emitting InAs Quantum Dots in InGaAs Matrix
Autorzy:
Persano, A.
Cola, A.
Vasanelli, L.
Convertino, A.
Leo, G.
Cerri, L.
Frassanito, M. C.
Viticoli, S.
Powiązania:
https://bibliotekanauki.pl/articles/2041798.pdf
Data publikacji:
2005-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.67.Hc
73.63.Kv
81.07.Ta
Opis:
We present a study of photoelectrical properties of the Stranski-Krastanow InAs quantum dots embedded in an InGaAs matrix with low In content, emitting at about 1.3μm. The ground-state electron-hole transition of the dots was investigated as a function of the temperature in presence of electric fields parallel and perpendicular to the plane of the dots by photocurrent spectroscopy. Microphotoluminescence measurements were also carried out, allowing us to evidence carrier capture from the GaAs matrix into the dots.
Źródło:
Acta Physica Polonica A; 2005, 107, 2; 381-387
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spin Thermoelectric Effects in Transport through a Two-Level Quantum Dot Coupled to Ferromagnetic Leads
Autorzy:
Karwacki, Ł.
Trocha, P.
Barnaś, J.
Powiązania:
https://bibliotekanauki.pl/articles/1427587.pdf
Data publikacji:
2012-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.21.La
73.23.-b
73.63.Kv
73.50.Lw
Opis:
We investigate spin thermoelectric effects in a two-level quantum dot attached to external ferromagnetic leads. The basic thermoelectric coefficients are calculated by means of the non-equilibrium Green functions approach in the mean field approximation for the Coulomb term. Specifically, we calculate spin-dependent thermopower (spin Seebeck coefficient) and the charge thermopower. These coefficients measure spin and charge voltage drops across the device, respectively. Moreover, the figure of merit and its spin analog (which measures the spin thermoelectric efficiency) are presented and discussed. We also show that the indirect (via the leads) coupling between the dot's levels can significantly enhance the thermoelectric effects.
Źródło:
Acta Physica Polonica A; 2012, 121, 5-6; 1207-1209
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mesoscopic Structures for Microwave-THz Detection
Autorzy:
Sužied.elis, A.
Ašmontas, S.
Požela, J.
Kundrotas, J.
Širmulis, E.
Gradauskas, J.
Kozič, A.
Kazlauskaité, V.
Anbinderis, T.
Powiązania:
https://bibliotekanauki.pl/articles/1813189.pdf
Data publikacji:
2008-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.21.Fg
73.40.Kp
73.50.Lw
73.63.Kv
Opis:
Properties of microwave detectors of various design on the base of MBE grown GaAs and AlGaAs structures are discussed in this paper: simple asymmetrically shaped structures with heavily doped GaAs and AlGaAs layers of nanometric thickness as well as diodes with two-dimensional electron gas layers. Novel models of the detectors with partially gated two-dimensional electron gas layer as well as with small area GaAs/AlGaAs heterojuction are discussed to demonstrate different ways to increase the voltage sensitivity of the detectors of electromagnetic radiation in GHz-THz frequency range.
Źródło:
Acta Physica Polonica A; 2008, 113, 3; 803-809
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phonon-Assisted Kondo Resonance in Spin-Dependent Transport through a Quantum Dot
Autorzy:
Świrkowicz, R.
Wilczyński, M.
Barnaś, J.
Powiązania:
https://bibliotekanauki.pl/articles/1810522.pdf
Data publikacji:
2009-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.23.Hk
73.63.Kv
73.43.Qt
72.25.-b
Opis:
Effects of local vibrational modes on electron transport through a quantum dot attached to ferromagnetic electrodes are studied in the Kondo regime by the non-equilibrium Green function formalism based on the equation of motion method. Differential conductance is calculated for parallel and antiparallel configurations of the leads' magnetic moments, and well defined Kondo resonance peaks and their phonon satellites are found. The influence of a compensating magnetic field on the peak positions is also discussed.
Źródło:
Acta Physica Polonica A; 2009, 115, 1; 272-274
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electron Transport through Double Quantum Dot: from SU(4) Kondo to SU(2) Symmetry
Autorzy:
Sztenkiel, D.
Świrkowicz, R.
Powiązania:
https://bibliotekanauki.pl/articles/2047706.pdf
Data publikacji:
2007-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.63.Kv
72.15.Qm
73.40.Gk
73.23.Hk
Opis:
Electron transport across two capacitively coupled quantum dots in a parallel geometry is theoretically studied in the non-linear response regime with spin and orbital degrees of freedom taken into account and the Kondo effect induced by on-site and inter-dot Coulomb correlations is analyzed. For a system with each dot symmetrically coupled to a separate set of electrodes a well-defined spin and orbital contributions to zero-bias Kondo resonance are obtained. The Kondo peak splits if spin and/or orbital degeneracies are removed. A suppression of the orbital Kondo anomaly due to orbital asymmetry and channel mixing effects is discussed.
Źródło:
Acta Physica Polonica A; 2007, 112, 2; 387-393
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Statistics of Conductance and Shot-Noise Power for Chaotic Cavities
Autorzy:
Sommers, H.-J.
Wieczorek, W.
Savin, D. V.
Powiązania:
https://bibliotekanauki.pl/articles/2047832.pdf
Data publikacji:
2007-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.23.-b
73.50.Td
05.45.Mt
73.63.Kv
Opis:
We report on an analytical study of the statistics of conductance, g, and shot-noise power, p, for a chaotic cavity with arbitrary numbers N$\text{}_{1,2}$ of channels in two leads and symmetry parameterβ = 1, 2, 4. With the theory of Selberg's integral the first four cumulants of g and first two cumulants of p are calculated explicitly. We give analytical expressions for the conductance and shot-noise distributions and determine their exact asymptotics near the edges up to linear order in distances from the edges. For 0 < g < 1 a power law for the conductance distribution is exact. All results are also consistent with numerical simulations.
Źródło:
Acta Physica Polonica A; 2007, 112, 4; 691-697
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
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:
Singlet-Triplet Switching Induced by Electric Field in Triple Quantum Dots
Autorzy:
Łuczak, J.
Bułka, B.
Powiązania:
https://bibliotekanauki.pl/articles/1427582.pdf
Data publikacji:
2012-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.10.-w
33.57.+c
73.23.-b
73.63.Kv
Opis:
We analyze influence of an external electric field on magnetic properties of a triple quantum dot system in a triangular and linear geometry. The system contains four electrons and is described by an extended Hubbard model which includes electron correlations and exchange processes. The electric field leads to splitting of energy levels (the Stark effect) and to transition between the singlet and triplet states.
Źródło:
Acta Physica Polonica A; 2012, 121, 5-6; 1195-1197
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
Tytuł:
Spin Thermoelectric Effects in a Strongly Correlated Double Quantum Dot System
Autorzy:
Karwacki, Ł.
Powiązania:
https://bibliotekanauki.pl/articles/1386717.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.23.-b
73.63.Kv
72.15.Qm
85.35.Ds
Opis:
Spin thermoelectric effects through a strongly correlated double quantum dot system embedded in a Aharonov-Bohm ring coupled to two leads with Rashba spin-orbit coupling have been investigated theoretically by means of the finite-U slave-boson technique. This method provides a reliable description of electron transport through quantum dot systems in the low temperature regime T ≪ $T_{K}$, where $T_{K}$ is the so-called Kondo temperature. Particular emphasis is put on the possibility of the so-called spin Seebeck effect in such a system as a more sensitive probe of the Kondo state.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 478-480
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:
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:
Transport through Single-Wall Carbon Nanotubes Weakly Coupled to External Leads
Autorzy:
Weymann, I.
Krompiewski, S.
Barnaś, J.
Powiązania:
https://bibliotekanauki.pl/articles/1810542.pdf
Data publikacji:
2009-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.25.Mk
73.63.Kv
85.75.-d
73.23.Hk
Opis:
We consider transport properties of single-wall metallic carbon nanotubes weakly coupled to external leads. In particular, we analyze the conductance and shot noise of nanotubes coupled to nonmagnetic leads and show that the shot noise may become super-Poissonian depending on the ground state of the nanotube. In addition, we also show that when the nanotube is coupled to one ferromagnetic and one nonmagnetic lead, it can operate as a gate-controlled spin diode.
Źródło:
Acta Physica Polonica A; 2009, 115, 1; 296-298
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-50 z 60

Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies