Temat: 72.25.Dc - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Application of the Picosecond Magnetic Pulses for Inducing the Electron Motion in the Bilayer Nanowire
Autorzy:: Chwiej, T.
Tematy:: 72.25.Dc
73.21.Hb; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1185398.pdf Link otwiera się w nowym oknie
Opis:: We theoretically study the effects of interaction of the single electron confined in a piece of bilayer nanowire with the picosecond magnetic pulse. It is shown that the transverse time-varying magnetic field hybridizes temporarily the vertical modes in the electron wave function which eventually stimulates its motion along the wire axis. The dynamics of such magnetically driven motion depends on the geometry of the confining potential, the effective mass of the electron and the time duration of the magnetic pulse. We show that this effect can potentially be utilized for fabrication of the magnetic valve.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Spin Switch and Spin Amplifier: Magnetic Bipolar Transistor in the Saturation Regime
Autorzy:: Fabian, J.
Žutić, I.
Tematy:: 72.25.Dc
72.25.Mk; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2038211.pdf Link otwiera się w nowym oknie
Opis:: It is shown that magnetic bipolar transistors can amplify currents even in the saturation regime, in which both the emitter-base and collector-base junctions are forward biased. The collector current and the current gain can change sign as they depend on the relative orientation of the equilibrium spin in the base and on the nonequilibrium spin in the emitter and collector. The predicted phenomena should be useful for electrical detection of nonequilibrium spins in semiconductors, as well as for magnetic control of current amplification and for current switching.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Spin Conductance of Nanowires with Double Coupled Quantum Dots
Autorzy:: Wołoszyn, M.
Spisak, B.
Wójcik, P.
Adamowski, J.
Tematy:: 72.25.Dc
73.63.Nm; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1398537.pdf Link otwiera się w nowym oknie
Opis:: 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.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Simulation of Spin-Dependent Electronic Transport through Resonant Tunnelling Diode with Paramagnetic Quantum Well
Autorzy:: Wójcik, P.
Spisak, B. J.
Wołoszyn, M.
Adamowski, J.
Tematy:: 72.25.Dc
73.63.-b; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2048076.pdf Link otwiera się w nowym oknie
Opis:: The spin-dependent electronic transport is investigated in a paramagnetic resonant tunnelling diode formed from Zn$\text{}_{1 - x}$Mn$\text{}_{x}$Se quantum well between two ZnBeSe barrier layers. The spin-dependent current-voltage characteristics have been obtained in the presence of magnetic fields by solving the quantum kinetic equation for the Wigner distribution function and the Poisson equation in the self-consistent procedure. We have obtained two distinct current peaks due to the giant Zeeman splitting of electronic levels in a qualitative agreement with experiment. We have shown that the sign of spin current polarization can be reversed by tuning the bias voltage. Moreover, we have found the bias voltage windows with a nearly constant polarization.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Magnetic properties of hexagonal graphene nanomeshes
Autorzy:: Zwierzycki, M.
Ryndyk, D.
Tematy:: 73.22.Pr
75.75.-c
72.25.Dc; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1054780.pdf Link otwiera się w nowym oknie
Opis:: Graphene nanomeshes are the nanostructures consisting of graphene flake with a regular pattern of antidots (holes) punched through it. Thanks to the energy gaps opening in electronic spectrum, nanomesh-based transistors offer improved I_{on}/I_{off} ratio of the collector current while supporting up to 100 larger driving currents than nanoribbon-based devices. In this paper the electronic and magnetic structure of graphene nanomeshes with hexagonally shaped antidots was studied. It has been found that the internal zigzag edges support magnetic moments and that lowest energy magnetic configuration is antiferromagnetic. The density of states calculated for ground state configuration exhibit the energy gap which can be substantially reduced upon switching (e.g. by external magnetic field) to ferromagnetic configuration. Based on this we predict that the structure will exhibit magnetoresistive effect, which makes graphene nanomeshes of this kind relevant for spintronic applications.
Dostawca treści:: Biblioteka Nauki

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na półce

Skocz do pozycji: 6.

Tytuł:: Spin Dependent Fano Resonances in a Rashba System with Coulomb Interactions
Autorzy:: Stefański, P.
Tematy:: 73.23.-b
72.25.Dc
73.40.Sx; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2048075.pdf Link otwiera się w nowym oknie
Opis:: The effects of interplay of interference of quantum mechanical electron waves and their mutual Coulomb interactions are investigated in the device composed of interacting quantum dot attached to polarized leads via quantum point contacts with the Rashba interaction. The Zeeman-split dot sub-levels form two interfering channels and as a result spin dependent Fano resonances arise in the conductance through the system. The Coulomb repulsion between the channels modifies the width and shape of the Fano resonances as compared to the non-interacting case. We formulate the Fano expression dependent on the dot's occupancy regulated by the Coulomb interactions.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Spin and Charge Current in a Short Semiconducting Chain of Paramagnetic Ionic Blocks
Autorzy:: Lehmann-Szweykowska, A.
Wojciechowski, R.
Micnas, R.
Tematy:: 72.25.Dc
73.61.Le
73.63.Rt; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1810512.pdf Link otwiera się w nowym oknie
Opis:: We deal with the electric current flowing through a short chain of paramagnetic ionic blocks, coupled to metallic electrodes in the serial configuration. An original three-band Hubbard-Anderson Hamiltonian is diagonalised at the level of the single ionic block. A minimal but sufficient set of the latter's four hybridised eigenstates serves as a basis for the determination of the time-ordered temperature-dependent matrix Green functions, in terms of which all the current-voltage (I-V) characteristics can be expressed provided the coupling to the electrodes is weak. The separation of the opposite-spin contributions to the electric current and, consequently, the spin current from the left to right electrode can result from the on-site Coulomb repulsion term of Hubbard-Anderson Hamiltonian, with no spin polarisation at the electrodes, but with the Zeeman-like coupling of the centre to either a molecular or an external magnetic field.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Doping Dependence of Spin Dynamics of Drifting Electrons in GaAs Bulks
Autorzy:: Spezia, S.
Persano Adorno, D.
Pizzolato, N.
Spagnolo, B.
Tematy:: 71.70.Ej
72.25.Dc
72.25.Rb; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1506224.pdf Link otwiera się w nowym oknie
Opis:: We study the effect of the impurity density on lifetimes and relaxation lengths of electron spins in the presence of a static electric field in an n-type GaAs bulk. The transport of electrons and the spin dynamics are simulated by using a semiclassical Monte Carlo approach, which takes into account the intravalley scattering mechanisms of warm electrons in the semiconductor material. Spin relaxation is considered through the D'yakonov-Perel mechanism, which is the dominant mechanism in III-V semiconductors. The evolution of spin polarization is analyzed by computing lifetimes and depolarization lengths as a function of the doping density in the range $10^{13}$ ÷ 5 × $10^{16} cm^{-3}$, for different values of the amplitude of the static electric field (0.1 ÷ 1.0 kV/cm). We find an increase of the electron spin lifetime as a function of the doping density, more evident for lattice temperatures lower than 150 K. Moreover, at very low intensities of the driving field, the spin depolarization length shows a nonmonotonic behaviour with the density. At the room temperature, spin lifetimes and depolarization lengths are nearly independent on the doping density. The underlying physics is analyzed.
Dostawca treści:: Biblioteka Nauki

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na półce

Skocz do pozycji: 9.

Tytuł:: Multilayer Transitions in Mixed Spin-3/2 and~1/2 Blume-Capel Model with RKKY Interaction
Autorzy:: El Hallani, F.
Ez-Zahraouy, H.
Benyoussef, A.
Bahmad, L.
Tematy:: 66.30.Xj
72.20.Dp
72.20.My
72.25.Dc; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1493617.pdf Link otwiera się w nowym oknie
Opis:: We studied the effect of the Ruderman-Kittel-Kasuya-Yosida interaction on the multilayer transition and magnetic properties of spins-3/2 and 1/2 Blume-Capel model in the bilayer separated by a non-magnetic spacer of thickness (d), by using mean-field theory and Monte Carlo simulation. It is found that the multilayer transition temperature depends strongly on the thickness of the non-magnetic layer and the crystal field. Furthermore, the critical thickness of the non-magnetic spacer above which the two magnetic multilayers transit separately depends on the Fermi level and the absolute temperature.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Anomalous Hall Effect in IV-VI Semiconductors
Autorzy:: Dyrdał, A.
Dugaev, V.
Barnaś, J.
Brodowska, B.
Dobrowolski, W.
Tematy:: 72.20.-i
75.50.Pp
72.25.Dc; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1810533.pdf Link otwiera się w nowym oknie
Opis:: We consider theoretically the topological contribution to the anomalous Hall effect in narrow-gap IV-VI magnetic semiconductors in which the relativistic terms are relatively large and determine both the non-parabolicity of the energy spectrum and strong spin-orbit interaction. We use the relativistic Dirac model and linear response theory to calculate this contribution. Experimental data on the anomalous Hall effect in these compounds are also presented and discussed.
Dostawca treści:: Biblioteka Nauki

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