Temat: 74.50.+r - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Diagrammatic Perturbation Technique for a Quantum Dot Connected to Superconducting Leads
Autorzy:: Pokorný, V.
Janiš, V.
Novotný, T.
Žonda, M.
Powiązania:: https://bibliotekanauki.pl/articles/1201960.pdf
Data publikacji:: 2014-07
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 71.15.-m
73.21.La
74.50.+r
Opis:: We study spectral properties of a quantum dot attached to two superconductors with nonzero phase difference. The system is described as a single-impurity Anderson model coupled to BCS superconducting leads. We utilize diagrammatic perturbation expansion in the Coulomb interaction to capture relevant physical phenomena, particularly the effect of the Coulomb interaction on the Andreev bound states present in the electronic spectrum. Results of the Hartree-Fock and the random phase approximations at zero temperature are presented.
Źródło:: Acta Physica Polonica A; 2014, 126, 1; 352-353
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Probing Fractional Josephson Junction with a Quantum Dot
Autorzy:: Stefański, P.
Powiązania:: https://bibliotekanauki.pl/articles/1398600.pdf
Data publikacji:: 2016-08
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 73.63.-b
73.21.La
74.78.Na
74.50.+r
Opis:: We consider theoretically a junction between two topological superconducting wires, mediated by a quantum dot. The wires are modelled by the Kitaev chains tuned into topological phase, which possess unpaired Majorana states at their ends. We derive the low energy Hamiltonian of the model. The Majorana states closer to the dot convert into the Dirac fermion inside the dot, forming fractional Josephson junction. The dot is additionally weakly coupled to the normal tunneling probe allowing transport measurement through the dot. When the topological wires are short, the unpaired Majorana end-states can hybridize inside the wire forming an extended Dirac fermionic state. It yields the destruction of the extended state in the dot. We discuss the dependence of the spectral density of the dot and its conductance on superconducting phase. We show that the conservation of parity of the junction, crucial for successful measurement of the fractional effect, can be assured by the gate voltage manipulation of the dot level position and that in case of an unpaired Majorana state in the junction a half conductance quantum can be observed.
Źródło:: Acta Physica Polonica A; 2016, 130, 2; 554-557
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Majorana States in Presence of Electron Interactions: Spinful Fractional Josephson Junction with a Quantum Dot
Autorzy:: Stefański, P.
Powiązania:: https://bibliotekanauki.pl/articles/1029763.pdf
Data publikacji:: 2018-03
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 73.63.-b
73.21.La
31.15.V-
74.50.+r
Opis:: We consider a fractional Josephson junction mediated by a quantum dot in which the Zeeman field arising from the magnetic fields driving left and right wires into topological phase can be tuned. Both fields, forming an angle Θp, can be rotated in the common plane perpendicular to the spin-orbit field in the wires. For Θp=0 the dot can be regarded as effectively non-interacting due to the large Zeeman splitting, whereas for Θp ≤sssimπ electron interactions are switched on the dot, affecting Majorana states. The tunnel electrode, weakly coupled to the dot from the top, allows to probe their density of states via conductance measurement. We show that electron interactions renormalize Majorana peak and introduce characteristic asymmetry in the gate voltage dependence of the transverse zero-bias conductance through the dot.
Źródło:: Acta Physica Polonica A; 2018, 133, 3; 362-365
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Electronic structure calculations of InP-based coupled quantum dot-quantum well structures
Autorzy:: Andrzejewski, J.
Powiązania:: https://bibliotekanauki.pl/articles/1160527.pdf
Data publikacji:: 2016-01
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 73.21.La
73.21.Fg
73.22.Dj
74.50.+r
Opis:: In this work we investigate the electronic structure of coupled 0D-2D nanostructures. The respective confined state energy levels in a quantum dot-quantum well system are calculated for various conduction band offsets - between the quantum dot and surrounding material. The calculated electron and hole energy levels with their wave functions allow determining if the wave functions are within the injector quantum well or within the quantum dot and if the carrier positions on the energy scale are appropriate from the point of view of a possible laser structure utilizing the so-called tunnel injection scheme. It is shown that for an adequate width of an injector quantum well and the conduction band offsets designing an optimal tunnel injection structure is possible.
Źródło:: Acta Physica Polonica A; 2016, 129, 1a; A-97-A-99
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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