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1
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Computer Simulations of Electron Transport through a Nanowire Quantum Dot

100%
Łapa D., Sowa A., Adamowski J.
Acta Physica Polonica A
|
2008
|
vol. 114
|
issue 5
1213-1218
EN
Electron tunneling through a quantum dot embedded in a nanowire was studied by the transfer matrix method. A smoothness of the interfaces was taken into account using the analytical parametrization of the potential profile. We calculated the current-voltage characteristics and discussed the effect of the spacer, which separates the quantum dot from the contacts. We found that the tunneling current peak possesses the asymmetric Fano resonance shape in the absence of spacer. The results of calculations agree with the experimental data.
2
Content available remote

Spin Conductance of Nanowires with Double Coupled Quantum Dots

63%
Wołoszyn M., Spisak B., Wójcik P., Adamowski J.
|
EN
Using the computer simulations we have studied the spin conductance of the InAs nanowire with three all-around gates that generate two coupled quantum dots in the nanowire. We have assumed that the same constant voltage is applied to the outermost (left and right) gates and investigated the effect of the varying central-gate voltage (V_{G}) and axially directed magnetic field B on the spin currents. The calculated spin-up and spin-down conductances exhibit pronounced oscillations as functions of V_{G}. In certain intervals of V_{G}, both the spin conductances oscillate in antiphase, which can be applied to the spin-filter operation.
3
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Nanodevice for High Precision Readout of Electron Spin

51%
Szumniak P., Bednarek S., Szafran B., Grynkiewicz P.
Acta Physica Polonica A
|
2011
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vol. 119
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issue 5
651-653
EN
In this paper we propose and simulate operation of a nanodevice, which enables the electron spin accumulation and very precise read-out of its final value. We exploit the dependence of the electron trajectory on its spin state due to the spin-orbit coupling in order to distinguish between different spin orientations.
4
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Transport Characteristics of Gated Core-Multishell Nanowires: Self-Consistent Approach

51%
Palutkiewicz T., Wołoszyn M., Wójcik P., Spisak B.
Acta Physica Polonica A
|
2016
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vol. 130
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issue 5
1190-1192
EN
The influence of the applied gate voltage on the coherent propagation of the conduction electrons through the InGaAs/InP core-multishell nanowires with the surrounding gate is considered. The solution of the three-dimensional Schrödinger equation within the effective mass approximation is found using the adiabatic method. The electrostatic potential distribution generated by the all-around gate is determined from the self-consistent procedure applied to the Schrödinger-Poisson problem. The Landauer-Büttiker formalism and quantum transmission boundary method are applied to calculate the transport properties of the considered nanosystem.
5
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Spin-Dependent Transport through Metallic System with Magnetic Impurities

51%
Spisak B., Wołoszyn M., Paja A.
Acta Physica Polonica A
|
2009
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vol. 115
|
issue 1
266-268
EN
The problem of spin-dependent transport of electrons through a metallic nanostructure is considered. The system consists of non-magnetic metal wire with two magnetic impurities and is connected to two ferromagnetic leads. The differential conductance is calculated by using the transfer matrix method. The spin polarization of the conductance is also obtained. It was found that this polarization is dependent on the spin configuration of magnetic impurities. This dependence can be controlled by the applied bias voltage.
6
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Spin Conductance of the Quantum Wire

51%
Dargys A.
Acta Physica Polonica A
|
2008
|
vol. 113
|
issue 3
937-942
EN
Spin transport in a semiconducting quantum wire connected to two spin-unpolarized electron reservoirs is investigated. The spin-orbit interaction is included via the Rashba Hamiltonian which together with the Zeeman Hamiltonian determines spin-filtering properties of the wire. The spin current as a function of the voltage was found to have an oscillatory or growing character.
7
Content available remote

Influence of Geometrical Parameters on the Transport Characteristics of Gated Core-Multishell Nanowires

51%
Palutkiewicz T., Wołoszyn M., Wójcik P., Adamowski J., Spisak B.
|
EN
Calculations of the current-voltage characteristics of the core-multishell nanowires for different radii of the core and various thicknesses of the shells are presented. A role of the conducting core and shells in the coherent transport under the influence of the gate voltage is discussed.
8
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Influence of Dephasing and Geometrical Parameters on Quantum Correction to DC Conductance of Cylindrical Nanowires

51%
Spisak B., Wołoszyn M., Wójcik P.
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EN
Calculations of the quantum correction to the DC conductance of a cylindrical nanowire due to the quantum interference are presented. The real space Cooperon equation is solved for cylindrical geometry. Using this approach, it is shown that the quantum correction to the conductance in the weak localisation regime depends not only on the dephasing processes but also on geometrical parameters of the nanowire.
9
Content available remote

Single Electron Spin Operations Employed for Logical Gates of Quantum Computer

51%
Bednarek S., Dudek R.
Acta Physica Polonica A
|
2009
|
vol. 116
|
issue S
S-7-S-12
EN
Electron localized in a quantum dot in the vicinity of conductor surface, causes an induced potential to appear. This potential enables self-focusing of electron wave function. Because of this feature, in a planar nanostructure consisting of a quantum well covered with a layer of an insulator, on top of which metal electrodes are deposited, formation of induced dots and quantum wires is possible. By applying appropriate voltages to the electrodes, it is feasible to transport an electron in a fully controllable way in a form of a stable wave packet between two specific locations in a nanodevice. While transporting an electron along properly shaped closed loops, spin-orbit coupling intrinsically present in a semiconductor nanostructure can be employed to perform operations on an electron spin.
10
Content available remote

Spin-dependent transport through magnetic nanojunctions

38%
Walczak K., Platero G.
Open Physics
|
2006
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vol. 4
|
issue 1
30-41
EN
Coherent electronic transport through a molecular device is studied using non-equilibrium Green's function (NEGF) formalism. Such device is made of atomic nanowire which is connected to ferromagnetic electrodes. The molecule itself is described with the help of Hubbard model (Coulomb interactions are treated by means of the Hartree-Fock approximation), while the coupling to the electrodes is modeled through the use of a broad-band theory. It was shown that magnetoresistance varies periodically with increasing length of the atomic wire (in the linear response regime) and oscillates with increasing bias voltage (in the nonlinear response regime). Since the TMR effect for analyzed structures is predicted to be large (tens of percent), these junctions seem to be suitable for application as magnetoresistive elements in future electronic circuits.
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