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Author |
Chaves, A.; Farias, G.A.; Peeters, F.M.; Szafran, B. |
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Title |
Wave packet dynamics in semiconductor quantum rings of finite width |
Type |
A1 Journal article |
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Year |
2009 |
Publication |
Physical review : B : solid state |
Abbreviated Journal |
Phys Rev B |
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Volume |
80 |
Issue |
12 |
Pages |
125331,1-125331,14 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The time evolution of a wave packet injected into a semiconductor quantum ring is investigated in order to obtain the transmission and reflection probabilities. Within the effective-mass approximation, the time-dependent Schrödinger equation is solved for a system with nonzero width of the ring and leads and finite potential-barrier heights, where we include smooth lead-ring connections. In the absence of a magnetic field, an analysis of the projection of the wave function over the different subband states shows that when the injected wave packet is within a single subband, the junction can scatter this wave packet into different subbands but remarkably at the second junction the wave packet is scattered back into the subband state of the incoming wave packet. If a magnetic field is applied perpendicularly to the ring plane, transmission and reflection probabilities exhibit Aharonov-Bohm (AB) oscillations and the outgoing electrons may end up in different subband states from those of the incoming electrons. Localized impurities, placed in the ring arms, influence the AB oscillation period and amplitude. For a single impurity or potential barrier of sufficiently strong strength, the period of the AB oscillations is halved while for two impurities localized in diametrically opposite points of the ring, the original AB period is recovered. A theoretical investigation of the confined states and time evolution of wave packets in T wires is also made, where a comparison between this system and the lead-ring junction is drawn. |
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Place of Publication |
Lancaster, Pa |
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Wos |
000270383300098 |
Publication Date |
2009-09-25 |
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Series Volume  |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
40 |
Open Access |
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Notes |
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Approved |
Most recent IF: 3.836; 2009 IF: 3.475 |
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Call Number |
UA @ lucian @ c:irua:79231 |
Serial |
3906 |
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Author |
Zebrowski, D.P.; Peeters, F.M.; Szafran, B. |
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Title |
Driven spin transitions in fluorinated single- and bilayer-graphene quantum dots |
Type |
A1 Journal article |
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Year |
2017 |
Publication |
Semiconductor science and technology |
Abbreviated Journal |
Semicond Sci Tech |
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Volume |
32 |
Issue |
6 |
Pages |
065016 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Spin transitions driven by a periodically varying electric potential in dilute fluorinated graphene quantum dots are investigated. Flakes of monolayer graphene as well as electrostatic electron traps induced in bilayer graphene are considered. The stationary states obtained within the tight-binding approach are used as the basis for description of the system dynamics. The dilute fluorination of the top layer lifts the valley degeneracy of the confined states and attenuates the orbital magnetic dipole moments due to current circulation within the flake. The spin-orbit coupling introduced by the surface deformation of the top layer induced by the adatoms allows the spin flips to be driven by the AC electric field. For the bilayer quantum dots the spin flip times is substantially shorter than the spin relaxation. Dynamical effects including many-photon and multilevel transitions are also discussed. |
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Place of Publication |
London |
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Language |
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Wos |
000402405800007 |
Publication Date |
2017-04-19 |
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Series Editor |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0268-1242 |
ISBN |
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Additional Links |
UA library record; WoS full record |
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Impact Factor |
2.305 |
Times cited |
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Open Access |
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Notes |
; This work was supported by the National Science Centre according to decision DEC-2013/11/B/ST3/03837 and by the Flemish Science Foundation (FWO-VL). ; |
Approved |
Most recent IF: 2.305 |
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Call Number |
UA @ lucian @ c:irua:144238 |
Serial |
4646 |
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Author |
Zebrowski, D.P.; Peeters, F.M.; Szafran, B. |
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Title |
Double quantum dots defined in bilayer graphene |
Type |
A1 Journal article |
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Year |
2017 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
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Volume |
96 |
Issue |
3 |
Pages |
035434 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Artificial molecular states of double quantum dots defined in bilayer graphene are studied with the atomistic tight-binding method and its low-energy continuum approximation. We indicate that the extended electron wave functions have opposite parities on sublattices of the layers and that the ground-state wave-function components change from bonding to antibonding with the interdot distance. In the weak-coupling limit, the one most relevant for quantum dots defined electrostatically, the signatures of the interdot coupling include, for the two-electron ground state, formation of states with symmetric or antisymmetric spatial wave functions split by the exchange energy. In the high-energy part of the spectrum the states with both electrons in the same dot are found with the splitting of energy levels corresponding to simultaneous tunneling of the electron pair from one dot to the other. |
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Publisher |
American Physical Society |
Place of Publication |
New York, N.Y |
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Language |
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Wos |
000406284200005 |
Publication Date |
2017-07-26 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2469-9969; 2469-9950 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
6 |
Open Access |
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Notes |
; ; |
Approved |
Most recent IF: 3.836 |
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Call Number |
UA @ lucian @ c:irua:145758 |
Serial |
4739 |
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Author |
Rzeszotarski, B.; Mrenca-Kolasinska, A.; Peeters, F.M.; Szafran, B. |
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Title |
Effective Landé factors for an electrostatically defined quantum point contact in silicene |
Type |
A1 Journal article |
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Year |
2021 |
Publication |
Scientific Reports |
Abbreviated Journal |
Sci Rep-Uk |
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Volume |
11 |
Issue |
1 |
Pages |
19892 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT) |
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Abstract |
The transconductance and effective Lande g* factors for a quantum point contact defined in silicene by the electric field of a split gate is investigated. The strong spin-orbit coupling in buckled silicene reduces the g* factor for in-plane magnetic field from the nominal value 2 to around 1.2 for the first-to 0.45 for the third conduction subband. However, for perpendicular magnetic field we observe an enhancement of g* factors for the first subband to 5.8 in nanoribbon with zigzag and to 2.5 with armchair edge. The main contribution to the Zeeman splitting comes from the intrinsic spin-orbit coupling defined by the Kane-Mele form of interaction. |
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Place of Publication |
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Wos |
000706380800089 |
Publication Date |
2021-10-08 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2045-2322 |
ISBN |
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Additional Links |
UA library record; WoS full record |
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Impact Factor |
4.259 |
Times cited |
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Open Access |
OpenAccess |
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Notes |
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Approved |
Most recent IF: 4.259 |
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Call Number |
UA @ admin @ c:irua:182502 |
Serial |
6983 |
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