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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:
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:
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:
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:
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:
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:
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:
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:
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

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