Records |
Author |
Lucena, D.; Ferreira, W.P.; Munarin, F.F.; Farias, G.A.; Peeters, F.M. |
Title |
Tunable diffusion of magnetic particles in a quasi-one-dimensional channel |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Physical review : E : statistical, nonlinear, and soft matter physics |
Abbreviated Journal |
Phys Rev E |
Volume |
87 |
Issue |
1 |
Pages |
012307-12309 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The diffusion of a system of ferromagnetic dipoles confined in a quasi-one-dimensional parabolic trap is studied using Brownian dynamics simulations. We show that the dynamics of the system is tunable by an in-plane external homogeneous magnetic field. For a strong applied magnetic field, we find that the mobility of the system, the exponent of diffusion, and the crossover time among different diffusion regimes can be tuned by the orientation of the magnetic field. For weak magnetic fields, the exponent of diffusion in the subdiffusive regime is independent of the orientation of the external field. DOI: 10.1103/PhysRevE.87.012307 |
Address |
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Corporate Author |
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Thesis |
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Publisher |
American Institute of Physics |
Place of Publication |
Woodbury (NY) |
Editor |
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Language |
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Wos |
000314152300005 |
Publication Date |
2013-01-15 |
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 |
1539-3755;1550-2376; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.366 |
Times cited |
11 |
Open Access |
|
Notes |
; This work was supported by CNPq, CAPES, FUNCAP (Pronex grant), the Flemish Science Foundation (FWO-Vl), the bilateral program between Flanders and Brazil, the collaborative program CNPq – FWO-Vl, and the Brazilian program Science Without Borders (CsF). Discussions with V. R. Misko are gratefully acknowledged. ; |
Approved |
Most recent IF: 2.366; 2013 IF: 2.326 |
Call Number |
UA @ lucian @ c:irua:110089 |
Serial |
3739 |
Permanent link to this record |
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Author |
Carvalho, J.C.N.; Nelissen, K.; Ferreira, W.P.; Farias, G.A.; Peeters, F.M. |
Title |
Diffusion in a quasi-one-dimensional system on a periodic substrate |
Type |
A1 Journal article |
Year |
2012 |
Publication |
Physical review : E : statistical, nonlinear, and soft matter physics |
Abbreviated Journal |
Phys Rev E |
Volume |
85 |
Issue |
2:1 |
Pages |
021136-021136,8 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The diffusion of charged particles interacting through a repulsive Yukawa potential, exp(-r/lambda)/r, confined by a parabolic potential in the y direction and subjected to a periodic substrate potential in the x direction is investigated. Langevin dynamic simulations are used to investigate the effect of the particle density, the amplitude of the periodic substrate, and the range of the interparticle interaction potential on the diffusive behavior of the particles. We found that in general the diffusion is suppressed with increasing the amplitude of the periodic potential, but for specific values of the strength of the substrate potential a remarkable increase of the diffusion is found with increasing the periodic potential amplitude. In addition, we found a strong dependence of the diffusion on the specific arrangement of the particles, e. g., single-chain versus multichain configuration. For certain particle configurations, a reentrant behavior of the diffusion is found as a function of the substrate strength due to structural transitions in the ordering of the particles. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
American Institute of Physics |
Place of Publication |
Woodbury (NY) |
Editor |
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Language |
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Wos |
000300671500007 |
Publication Date |
2012-02-24 |
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 |
|
ISSN |
1539-3755;1550-2376; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.366 |
Times cited |
9 |
Open Access |
|
Notes |
; This work was supported by the Brazilian agencies CNPq and FUNCAP (PRONEX-Grant), the Flemish Science Foundation (FWO-Vl), and the bilateral projects between Flanders and Brazil and the Flemish Science Foundation (FWO-VI) and CNPq. ; |
Approved |
Most recent IF: 2.366; 2012 IF: 2.313 |
Call Number |
UA @ lucian @ c:irua:97203 |
Serial |
698 |
Permanent link to this record |
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Author |
Zarenia, M.; Chaves, A.; Farias, G.A.; Peeters, F.M. |
Title |
Energy levels of triangular and hexagonal graphene quantum dots : a comparative study between the tight-binding and Dirac equation approach |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
84 |
Issue |
24 |
Pages |
245403-245403,12 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The Dirac equation is solved for triangular and hexagonal graphene quantum dots for different boundary conditions in the presence of a perpendicular magnetic field. We analyze the influence of the dot size and its geometry on their energy spectrum. A comparison between the results obtained for graphene dots with zigzag and armchair edges, as well as for infinite-mass boundary condition, is presented and our results show that the type of graphene dot edge and the choice of the appropriate boundary conditions have a very important influence on the energy spectrum. The single-particle energy levels are calculated as a function of an external perpendicular magnetic field that lifts degeneracies. Comparing the energy spectra obtained from the tight-binding approximation to those obtained from the continuum Dirac equation approach, we verify that the behavior of the energies as a function of the dot size or the applied magnetic field are qualitatively similar, but in some cases quantitative differences can exist. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000297767800008 |
Publication Date |
2011-12-07 |
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 |
|
Edition |
|
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
145 |
Open Access |
|
Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl), the Belgian Science Policy (IAP), the European Science Foundation (ESF) under the EUROCORES Program EuroGRAPHENE (project CONGRAN), the Bilateral program between Flanders and Brazil, CAPES and the Brazilian Council for Research (CNPq). ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
Call Number |
UA @ lucian @ c:irua:93961 |
Serial |
1040 |
Permanent link to this record |
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Author |
Pereira, J.M.; Peeters, F.M.; Costa Filho, R.N.; Farias, G.A. |
Title |
Valley polarization due to trigonal warping on tunneling electrons in graphene |
Type |
A1 Journal article |
Year |
2009 |
Publication |
Journal of physics : condensed matter |
Abbreviated Journal |
J Phys-Condens Mat |
Volume |
21 |
Issue |
4 |
Pages |
045301,1-045301,4 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The effect of trigonal warping on the transmission of electrons tunneling through potential barriers in graphene is investigated. We present calculations of the transmission coefficient for single and double barriers as a function of energy, incidence angle and barrier heights. The results show remarkable valley-dependent directional effects for barriers oriented parallel to the armchair or parallel to the zigzag direction. These results indicate that electrostatic gates can be used as valley filters in graphene-based devices. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
London |
Editor |
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Language |
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Wos |
000262354700004 |
Publication Date |
2008-12-20 |
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 |
|
ISSN |
0953-8984;1361-648X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.649 |
Times cited |
78 |
Open Access |
|
Notes |
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Approved |
Most recent IF: 2.649; 2009 IF: 1.964 |
Call Number |
UA @ lucian @ c:irua:75736 |
Serial |
3834 |
Permanent link to this record |
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Author |
de Sousa, G.O.; da Costa, D.R.; Chaves, A.; Farias, G.A.; Peeters, F.M. |
Title |
Unusual quantum confined Stark effect and Aharonov-Bohm oscillations in semiconductor quantum rings with anisotropic effective masses |
Type |
A1 Journal article |
Year |
2017 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
Volume |
95 |
Issue |
95 |
Pages |
205414 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The effects of external electric and magnetic fields on the energy spectrum of quantum rings made out of a bidimensional semiconductor material with anisotropic band structures are investigated within the effective-mass model. The interplay between the effective-mass anisotropy and the radial confinement leads to wave functions that are strongly localized at two diametrically opposite regions where the kinetic energy is lowest due to the highest effective mass. We show that this quantum phenomenon has clear consequences on the behavior of the energy states in the presence of applied in-plane electric fields and out-of-plane magnetic fields. In the former, the quantum confined Stark effect is observed with either linear or quadratic shifts, depending on the direction of the applied field. As for the latter, the usual Aharonov-Bohm oscillations are not observed for a circularly symmetric confining potential, however they can be reinstated if an elliptic ring with an appropriate aspect ratio is chosen. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
American Physical Society |
Place of Publication |
New York, N.Y |
Editor |
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Language |
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Wos |
000401230600007 |
Publication Date |
2017-05-12 |
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 |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
19 |
Open Access |
|
Notes |
; This work was financially supported by CNPq under the PRONEX/FUNCAP grants, CAPES Foundation, the Flemish Science Foundation (FWO-Vl), and the Brazilian Program Science Without Borders (CsF). ; |
Approved |
Most recent IF: 3.836 |
Call Number |
UA @ lucian @ c:irua:143746 |
Serial |
4610 |
Permanent link to this record |
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Author |
Sena, S.H.R.; Pereira, J.M.; Peeters, F.M.; Farias, G.A. |
Title |
Landau levels in asymmetric graphene trilayer |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
84 |
Issue |
20 |
Pages |
205448-205448,7 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The electronic spectrum of three coupled graphene layers (graphene trilayers) is investigated in the presence of an external magnetic field. We obtain analytical expressions for the Landau level spectrum for both the ABA and ABC type of stacking, which exhibit very different dependence on the magnetic field. We show that layer asymmetry and an external gate voltage can strongly influence the properties of the system. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000297295400018 |
Publication Date |
2011-11-21 |
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 |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
30 |
Open Access |
|
Notes |
; This work was supported by the Brazilian Council for Research (CNPq), the National Council for the Improvement of Higher Education (CAPES), the Flemish Science Foundation (FWO-Vl), the Belgian Science Policy (IAP), and the bilateral projects between Flanders and Brazil and the CNPq and FWO-Vl. ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
Call Number |
UA @ lucian @ c:irua:94026 |
Serial |
1773 |
Permanent link to this record |
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Author |
Lavor, I.R.; da Costa, D.R.; Chaves, A.; Farias, G.A.; Macedo, R.; Peeters, F.M. |
Title |
Magnetic field induced vortices in graphene quantum dots |
Type |
A1 Journal article |
Year |
2020 |
Publication |
Journal Of Physics-Condensed Matter |
Abbreviated Journal |
J Phys-Condens Mat |
Volume |
32 |
Issue |
15 |
Pages |
155501 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The energy spectrum and local current patterns in graphene quantum dots (QD) are investigated for different geometries in the presence of an external perpendicular magnetic field. Our results demonstrate that, for specific geometries and edge configurations, the QD exhibits vortex and anti-vortex patterns in the local current density, in close analogy to the vortex patterns observed in the probability density current of semiconductor QD, as well as in the order parameter of mesoscopic superconductors. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000520149200001 |
Publication Date |
2019-12-20 |
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 |
0953-8984 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.7 |
Times cited |
5 |
Open Access |
|
Notes |
; This work was financially supported by the CAPES foundation and CNPq (Science Without Borders, PQ and FUNCAP/PRONEX programs). ; |
Approved |
Most recent IF: 2.7; 2020 IF: 2.649 |
Call Number |
UA @ admin @ c:irua:167670 |
Serial |
6558 |
Permanent link to this record |
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Author |
de Oliveira, E.L.; Albuquerque, E.L.; de Sousa, J.S.; Farias, G.A.; Peeters, F.M. |
Title |
Configuration-interaction excitonic absorption in small Si/Ge and Ge/Si core/shell nanocrystals |
Type |
A1 Journal article |
Year |
2012 |
Publication |
The journal of physical chemistry: C : nanomaterials and interfaces |
Abbreviated Journal |
J Phys Chem C |
Volume |
116 |
Issue |
7 |
Pages |
4399-4407 |
Keywords |
A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT) |
Abstract |
The excitonic properties of Si(core)/Ge(shell) and Ge(core)/Si(shell) nanocrystals (NC's) with diameters of similar to 1.9 nm are investigated using a combination density functional ab initio method to obtain the single particle wave functions and a configuration interaction method to compute the exciton fine structure and absorption coefficient. These core/shell structures exhibit type II confinement, which is more pronounced for the Si/Ge NC as a consequence of strain. The absorption coefficients of these NC's exhibit a single dominant peak, which has a much larger oscillator strength than the multipeaks found for pure Si and Ge NC's. The exciton lifetime in Si, Ge, and Ge/Si shows a small i:emperature dependence in the range 10-300 K, whereas in Si/Ge, the exciton lifetime decreases more than an order of magnitude in the same temperature range. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Washington, D.C. |
Editor |
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Language |
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Wos |
000301156500007 |
Publication Date |
2012-01-04 |
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 |
1932-7447;1932-7455; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
4.536 |
Times cited |
44 |
Open Access |
|
Notes |
; The authors acknowledge financial support from CNPq and the bilateral program between Flanders and Brazil and the Belgian Science Foundation (IAP). ; |
Approved |
Most recent IF: 4.536; 2012 IF: 4.814 |
Call Number |
UA @ lucian @ c:irua:113045 |
Serial |
482 |
Permanent link to this record |
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Author |
Ferreira, W.P.; Farias, G.A.; Carmona, H.A.; Peeters, F.M. |
Title |
Structural transitions in a classical two-dimensional molecule system |
Type |
A1 Journal article |
Year |
2002 |
Publication |
Solid state communications |
Abbreviated Journal |
Solid State Commun |
Volume |
122 |
Issue |
12 |
Pages |
665-669 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The ground state of a classical two-dimensional (2D) system with a finite number of charge particles, trapped by two positive impurity charges localized at a distance (z(0)) from the. 2D plane and separated from each other by a distance chi(p) are obtained. The impurities are allowed to carry more than one positive charge. This classical system can form a 2D-like classical molecule that exhibits structural transitions and spontaneous symmetry breaking as function of the separation between the positive charges before it transforms into two 2D-like classical atoms. We also observe structural transitions as a function of the dielectric constant of the substrate which supports the charged particles, in addition to broken symmetry states and unbinding of particles. (C) 2002 Elsevier Science Ltd. All rights reserved. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
New York, N.Y. |
Editor |
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Language |
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Wos |
000177129500008 |
Publication Date |
2002-10-11 |
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 |
0038-1098; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
1.554 |
Times cited |
3 |
Open Access |
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Notes |
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Approved |
Most recent IF: 1.554; 2002 IF: 1.671 |
Call Number |
UA @ lucian @ c:irua:95137 |
Serial |
3268 |
Permanent link to this record |
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Author |
de Sousa, J.S.; Covaci, L.; Peeters, F.M.; Farias, G.A. |
Title |
Time-dependent investigation of charge injection in a quantum dot containing one electron |
Type |
A1 Journal article |
Year |
2012 |
Publication |
Journal of applied physics |
Abbreviated Journal |
J Appl Phys |
Volume |
112 |
Issue |
9 |
Pages |
093705-93709 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The interaction of an injected electron towards a quantum dot (QD) containing a single confined electron is investigated using a flexible time-dependent quantum mechanics formalism, which allows both electrons to move and undergo quantum transitions. Different scenarios combining quantum dot dimensions, dielectric constant, injected wave packet energy, and width were explored, and our main results are: (i) due to the large characteristic transitions times between the confined state in the quantum dot and the delocalized state in the continuum, it is relatively difficult to ionize the occupied QD by Coulomb interaction solely and (ii) the charging state of the quantum dot can be sensed by direct injection of charges. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4759292] |
Address |
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Corporate Author |
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Thesis |
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Publisher |
American Institute of Physics |
Place of Publication |
New York, N.Y. |
Editor |
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Language |
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Wos |
000311968400052 |
Publication Date |
2012-11-06 |
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 |
0021-8979; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.068 |
Times cited |
1 |
Open Access |
|
Notes |
; This work was financially supported by the Brazilian National Research Council (CNPq), under Contract No. NanoBioEstruturas 555183/2005-0, Fundao Cearense de Apoio ao Desenvolvimento Cientfico e Tecnolgico (Funcap), CAPES, Pronex/CNPq/ Funcap, the Bilateral program between Flanders and Brazil, and the Flemish Science Foundation (FWO). ; |
Approved |
Most recent IF: 2.068; 2012 IF: 2.210 |
Call Number |
UA @ lucian @ c:irua:106014 |
Serial |
3664 |
Permanent link to this record |
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Author |
da Costa, D.R.; Chaves, A.; Farias, G.A.; Peeters, F.M. |
Title |
Valley filtering in graphene due to substrate-induced mass potential |
Type |
A1 Journal article |
Year |
2017 |
Publication |
Journal of physics : condensed matter |
Abbreviated Journal |
|
Volume |
29 |
Issue |
21 |
Pages |
215502 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The interaction of monolayer graphene with specific substrates may break its sublattice symmetry and results in unidirectional chiral states with opposite group velocities in the different Dirac cones (Zarenia et al 2012 Phys. Rev. B 86 085451). Taking advantage of this feature, we propose a valley filter based on a transversal mass kink for low energy electrons in graphene, which is obtained by assuming a defect region in the substrate that provides a change in the sign of the substrate-induced mass and thus creates a non-biased channel, perpendicular to the kink, for electron motion. By solving the time-dependent Schrodinger equation for the tight-binding Hamiltonian, we investigate the time evolution of a Gaussian wave packet propagating through such a system and obtain the transport properties of this graphene-based substrate-induced quantum point contact. Our results demonstrate that efficient valley filtering can be obtained, provided: (i) the electron energy is sufficiently low, i.e. with electrons belonging mostly to the lowest sub-band of the channel, and (ii) the channel length (width) is sufficiently long (narrow). Moreover, even though the transmission probabilities for each valley are significantly affected by impurities and defects in the channel region, the valley polarization in this system is shown to be robust against their presence. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000400092700002 |
Publication Date |
2017-04-24 |
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 |
0953-8984 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
|
Times cited |
15 |
Open Access |
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Notes |
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Approved |
no |
Call Number |
UA @ admin @ c:irua:152636 |
Serial |
8730 |
Permanent link to this record |
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Author |
Ferreira, W.P.; Farias, G.A.; Peeters, F.M. |
Title |
A two-component mixture of charged particles confined in a channel: melting |
Type |
A1 Journal article |
Year |
2010 |
Publication |
Journal of physics : condensed matter |
Abbreviated Journal |
J Phys-Condens Mat |
Volume |
22 |
Issue |
28 |
Pages |
11 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The melting of a binary system of charged particles confined in a quasi-one-dimensional parabolic channel is studied through Monte Carlo simulations. At zero temperature the particles are ordered in parallel chains. The melting is anisotropic and different melting temperatures are obtained according to the spatial direction, and the different kinds of particles present in the system. Melting is very different for the single-, two- and four-chain configurations. A temperature induced structural phase transition is found between two different four-chain ordered states which is absent in the mono-disperse system. In the mixed regime, where the two kinds of particles are only slightly different, melting is almost isotropic and a thermally induced homogeneous distribution of the distinct kinds of charges is observed. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
London |
Editor |
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Language |
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Wos |
000279257300023 |
Publication Date |
2010-06-16 |
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 |
0953-8984;1361-648X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.649 |
Times cited |
10 |
Open Access |
|
Notes |
; This work was supported by CNPq, the Flemish Science Foundation (FWO-V1) and the bilateral program between Flanders and Brazil. ; |
Approved |
Most recent IF: 2.649; 2010 IF: 2.332 |
Call Number |
UA @ lucian @ c:irua:83862 |
Serial |
3771 |
Permanent link to this record |
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|
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Author |
Munarin, F.F.; Ferreira, W.P.; Farias, G.A.; Peeters, F.M. |
Title |
Ground state and normal-mode spectra of a two-dimensional system of dipole particles confined in a parabolic trap |
Type |
A1 Journal article |
Year |
2008 |
Publication |
Physical review : E : statistical, nonlinear, and soft matter physics |
Abbreviated Journal |
Phys Rev E |
Volume |
78 |
Issue |
3 Part 1 |
Pages |
031405-31412 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The ordered configurations of a monolayer of interacting magnetic dipoles confined in a circular parabolic potential are investigated as a function of the dipole moment of the particles. Despite the circular confinement, we find very asymmetric ordered structures like chains and Y-shaped configurations when a magnetic field is applied parallel to the plane of the particles. The normal-mode spectrum of the particles and its dependence on the magnetic field and the strength of the dipole moment of the particles are studied. The vibrational and rotational modes of the spectrum, which are associated with the stability of the system, are investigated in detail. The number of particles is varied and we found different ordering of the particles for different values of the dipole moment and the magnetic field. A ring structure with a large number of particles is observed for high values of the dipole moment of the particles. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
American Institute of Physics |
Place of Publication |
Woodbury (NY) |
Editor |
|
Language |
|
Wos |
000259682700057 |
Publication Date |
2008-09-18 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1539-3755;1550-2376; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.366 |
Times cited |
5 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 2.366; 2008 IF: 2.508 |
Call Number |
UA @ lucian @ c:irua:103084 |
Serial |
1382 |
Permanent link to this record |
|
|
|
Author |
Ferreira, W.P.; Matulis, A.; Farias, G.A.; Peeters, F.M. |
Title |
Structure and correlations in two-dimensional classical artificial atoms confined by a Coulomb potential |
Type |
A1 Journal article |
Year |
2003 |
Publication |
Physical review : E : statistical, nonlinear, and soft matter physics |
Abbreviated Journal |
Phys Rev E |
Volume |
67 |
Issue |
4Part 2 |
Pages |
046601-46608 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The ordering of N equally charged particles (-e) moving in two dimensions and confined by a Coulomb potential, resulting from a displaced positive charge Ze is discussed. This is a classical model system for atoms. We obtain the configurations of charged particles which, depending on the value of N and Z, may result in ring structures, hexagonal-type configurations, and for N/Z approximate to 1 in an inner structure of particles which is separated by an outer ring of particles. For N/Z << 1, the Hamiltonian of the parabolic confinement case is recovered. For N/Z approximate to 1, the configurations are very different from those found in the case of a parabolic confinement potential. A hydrodynamic analysis is presented in order to highlight the correlations effects. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
American Institute of Physics |
Place of Publication |
Woodbury (NY) |
Editor |
|
Language |
|
Wos |
000182825400087 |
Publication Date |
2003-04-03 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1063-651X;1095-3787; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.366 |
Times cited |
14 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 2.366; 2003 IF: 2.202 |
Call Number |
UA @ lucian @ c:irua:104123 |
Serial |
3273 |
Permanent link to this record |
|
|
|
Author |
da Costa, D.R.; Chaves, A.; Farias, G.A.; Covaci, L.; Peeters, F.M. |
Title |
Wave-packet scattering on graphene edges in the presence of a pseudomagnetic field |
Type |
A1 Journal article |
Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
86 |
Issue |
11 |
Pages |
115434 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The scattering of a Gaussian wave packet in armchair and zigzag graphene edges is theoretically investigated by numerically solving the time-dependent Schrodinger equation for the tight-binding model Hamiltonian. Our theory allows us to investigate scattering in reciprocal space, and depending on the type of graphene edge we observe scattering within the same valley, or between different valleys. In the presence of an external magnetic field, the well-known skipping orbits are observed. However, our results demonstrate that in the case of a pseudomagnetic field, induced by nonuniform strain, the scattering by an armchair edge results in a nonpropagating edge state. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
|
Language |
|
Wos |
000309174100005 |
Publication Date |
2012-09-21 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
28 |
Open Access |
|
Notes |
; Discussions with E. B. Barros are gratefully acknowledged. This work was supported by the Brazilian Council for Research (CNPq), the Flemish Science Foundation (FWO-Vl), the ESF-EuroGRAPHENE (project CONGRAN), and the bilateral program between Flanders and Brazil. ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
Call Number |
UA @ lucian @ c:irua:101833 |
Serial |
3907 |
Permanent link to this record |
|
|
|
Author |
Chaves, A.; Farias, G.A.; Peeters, F.M.; Ferreira, R. |
Title |
The Split-operator technique for the study of spinorial wavepacket dynamics |
Type |
A1 Journal article |
Year |
2015 |
Publication |
Communications in computational physics |
Abbreviated Journal |
Commun Comput Phys |
Volume |
17 |
Issue |
17 |
Pages |
850-866 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The split-operator technique for wave packet propagation in quantum systems is expanded here to the case of propagatingwave functions describing Schrodinger particles, namely, charge carriers in semiconductor nanostructures within the effective mass approximation, in the presence of Zeeman effect, as well as of Rashba and Dresselhaus spin-orbit interactions. We also demonstrate that simple modifications to the expanded technique allow us to calculate the time evolution of wave packets describing Dirac particles, which are relevant for the study of transport properties in graphene. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
|
Wos |
000353695400010 |
Publication Date |
2015-03-24 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1815-2406;1991-7120; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.004 |
Times cited |
24 |
Open Access |
|
Notes |
; The authors gratefully acknowledge fruitful discussions with J. M. Pereira Jr. and R. N. Costa Filho. This work was financially supported by CNPq through the INCT-NanoBioSimes and the Science Without Borders programs (contract 402955/ 2012-9), PRONEX/FUNCAP, CAPES, the Bilateral programme between Flanders and Brazil, and the Flemish Science Foundation (FWO-Vl). ; |
Approved |
Most recent IF: 2.004; 2015 IF: 1.943 |
Call Number |
c:irua:126028 |
Serial |
3593 |
Permanent link to this record |
|
|
|
Author |
Ferreira, W.P.; Peeters, F.M.; Farias, G.A. |
Title |
Melting and evaporation in classical two-dimensional clusters confined by a Coulomb potential |
Type |
A1 Journal article |
Year |
2005 |
Publication |
Physical review : E : statistical, nonlinear, and soft matter physics |
Abbreviated Journal |
Phys Rev E |
Volume |
72 |
Issue |
4 Part 1 |
Pages |
041502-41507 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The thermal properties of a two-dimensional classical cluster of negatively charged particles bound by a punctual positive charge are presented. The melting phenomenon is analyzed and the features which characterize such a solid-liquid transition are highlighted. We found that the presence of metastable states strongly modifies the melting scenario, and that the melting temperature of the system is determined by the height of the saddle point energy separating the ground state and the metastable state. Due to the particular type of confinement potential considered in this paper, we also found that, at sufficiently large temperature, the cluster can become thermally ionized. |
Address |
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Corporate Author |
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Thesis |
|
Publisher |
American Institute of Physics |
Place of Publication |
Woodbury (NY) |
Editor |
|
Language |
|
Wos |
000232930600030 |
Publication Date |
2005-10-06 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1539-3755;1550-2376; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.366 |
Times cited |
4 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 2.366; 2005 IF: 2.418 |
Call Number |
UA @ lucian @ c:irua:104067 |
Serial |
1983 |
Permanent link to this record |
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|
|
Author |
Lavor, I.R.; da Costa, D.R.; Chaves, A.; Sena, S.H.R.; Farias, G.A.; Van Duppen, B.; Peeters, F.M. |
Title |
Effect of zitterbewegung on the propagation of wave packets in ABC-stacked multilayer graphene : an analytical and computational approach |
Type |
A1 Journal article |
Year |
2021 |
Publication |
Journal Of Physics-Condensed Matter |
Abbreviated Journal |
J Phys-Condens Mat |
Volume |
33 |
Issue |
9 |
Pages |
095503 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The time evolution of a low-energy two-dimensional Gaussian wave packet in ABC-stacked n-layer graphene (ABC-NLG) is investigated. Expectation values of the position (x, y) of center-of-mass and the total probability densities of the wave packet are calculated analytically using the Green's function method. These results are confirmed using an alternative numerical method based on the split-operator technique within the Dirac approach for ABC-NLG, which additionally allows to include external fields and potentials. The main features of the zitterbewegung (trembling motion) of wave packets in graphene are demonstrated and are found to depend not only on the wave packet width and initial pseudospin polarization, but also on the number of layers. Moreover, the analytical and numerical methods proposed here allow to investigate wave packet dynamics in graphene systems with an arbitrary number of layers and arbitrary potential landscapes. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000599465000001 |
Publication Date |
2020-11-25 |
Series Editor |
|
Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0953-8984 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.649 |
Times cited |
5 |
Open Access |
OpenAccess |
Notes |
; Discussions with D J P de Sousa and J M Pereira Jr are gratefully acknowledged. This work was financially supported by the Brazilian Council for Research (CNPq), under the PQ and PRONEX/FUNCAP programs, and by CAPES. One of us (BVD) is supported by the FWO-Vl. DRC is supported by CNPq Grant Nos. 310019/2018-4 and 437067/2018-1. ; |
Approved |
Most recent IF: 2.649 |
Call Number |
UA @ admin @ c:irua:174953 |
Serial |
6687 |
Permanent link to this record |
|
|
|
Author |
Chaves, A.; Covaci, L.; Rakhimov, K.Y.; Farias, G.A.; Peeters, F.M. |
Title |
Wave-packet dynamics and valley filter in strained graphene |
Type |
A1 Journal article |
Year |
2010 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
82 |
Issue |
20 |
Pages |
205430 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The time evolution of a wave packet in strained graphene is studied within the tight-binding model and continuum model. The effect of an external magnetic field, as well as a strain-induced pseudomagnetic field, on the wave-packet trajectories and zitterbewegung are analyzed. Combining the effects of strain with those of an external magnetic field produces an effective magnetic field which is large in one of the Dirac cones, but can be practically zero in the other. We construct an efficient valley filter, where for a propagating incoming wave packet consisting of momenta around the K and K' Dirac points, the outgoing wave packet exhibits momenta in only one of these Dirac points while the components of the packet that belong to the other Dirac point are reflected due to the Lorentz force. We also found that the zitterbewegung is permanent in time in the presence of either external or strain-induced magnetic fields, but when both the external and strain-induced magnetic fields are present, the zitterbewegung is transient in one of the Dirac cones, whereas in the other cone the wave packet exhibits permanent spatial oscillations. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
|
Editor |
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Language |
|
Wos |
000284401600007 |
Publication Date |
2010-11-19 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
95 |
Open Access |
|
Notes |
; This work was financially supported by CNPq under NanoBioEstruturas Contract No. 555183/2005-0, PRONEX/CNPq/FUNCAP, CAPES, the Bilateral program between Flanders and Brazil, the Belgian Science Policy (IAP), and the Flemish Science Foundation (FWO-V1) ; |
Approved |
Most recent IF: 3.836; 2010 IF: 3.774 |
Call Number |
UA @ lucian @ c:irua:95542 |
Serial |
3905 |
Permanent link to this record |
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|
|
Author |
Chaves, A.; Farias, G.A.; Peeters, F.M.; Szafran, B. |
Title |
Wave packet dynamics in semiconductor quantum rings of finite width |
Type |
A1 Journal article |
Year |
2009 |
Publication |
Physical review : B : solid state |
Abbreviated Journal |
Phys Rev B |
Volume |
80 |
Issue |
12 |
Pages |
125331,1-125331,14 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
|
Place of Publication |
Lancaster, Pa |
Editor |
|
Language |
|
Wos |
000270383300098 |
Publication Date |
2009-09-25 |
Series Editor |
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Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
40 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 3.836; 2009 IF: 3.475 |
Call Number |
UA @ lucian @ c:irua:79231 |
Serial |
3906 |
Permanent link to this record |
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Author |
Chaves, A.; Peeters, F.M.; Farias, G.A.; Milošević, M.V. |
Title |
Vortex-vortex interaction in bulk superconductors : Ginzburg-Landau theory |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
83 |
Issue |
5 |
Pages |
054516-054516,14 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The vortex-vortex interaction potential in bulk superconductors is calculated within the Ginzburg-Landau (GL) theory and is obtained from a numerical solution of a set of two coupled nonlinear GL differential equations for the vector potential and the superconducting order parameter, where the merger of vortices into a giant vortex is allowed. Further, the interaction potentials between a vortex and a giant vortex and between a vortex and an antivortex are obtained for both type-I and type-II superconductors. Our numerical results agree asymptotically with the analytical expressions for large intervortex separations that are available in the literature. We propose empirical expressions valid over the full interaction range, which are fitted to our numerical data for different values of the GL parameter. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000287712100009 |
Publication Date |
2011-02-25 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
31 |
Open Access |
|
Notes |
; Discussions with J. S. Andrade Jr. and A. A. Moreira are gratefully acknowledged. This work was financially supported by CNPq, under Contract No. NanoBioEstruturas 555183/2005-0, PRONEX/FUNCAP, CAPES, the Bilateral programme between Flanders and Brazil, the collaborative project CNPq-FWO-Vl, the Belgian Science Policy (IAP), and the Flemish Science Foundation (FWO-Vl). ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
Call Number |
UA @ lucian @ c:irua:88805 |
Serial |
3899 |
Permanent link to this record |
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|
Author |
de Araujo, J.L.B.; Munarin, F.F.; Farias, G.A.; Peeters, F.M.; Ferreira, W.P. |
Title |
Structure and reentrant percolation in an inverse patchy colloidal system |
Type |
A1 Journal article |
Year |
2017 |
Publication |
Physical Review E |
Abbreviated Journal |
|
Volume |
95 |
Issue |
6 |
Pages |
062606 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
Two-dimensional systems of inverse patchy colloids modeled as disks with a central charge and having their surface decorated with oppositely pointlike charged patches are investigated using molecular dynamics simulations. The self-assembly of the patchy colloids leads to diverse ground state configurations ranging from crystalline arrangements of monomers to linear clusters, ramified linear clusters and to percolated configurations. Two structural phase diagrams are constructed: (1) as a function of the net charge and area fraction, and (2) as a function of the net charge and the range of the pair interaction potential. An interesting reentrant percolation transition is obtained as a function of the net charge of the colloids. We identify distinct mechanisms that lead to the percolation transition. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000404545700005 |
Publication Date |
2017-06-27 |
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 |
|
ISSN |
|
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
|
Times cited |
5 |
Open Access |
|
Notes |
|
Approved |
no |
Call Number |
UA @ admin @ c:irua:152628 |
Serial |
8587 |
Permanent link to this record |
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Author |
Frota, D.A.; Chaves, A.; Ferreira, W.P.; Farias, G.A.; Milošević, M.V. |
Title |
Superconductor-ferromagnet bilayer under external drive : the role of vortex-antivortex matter |
Type |
A1 Journal article |
Year |
2016 |
Publication |
Journal of applied physics |
Abbreviated Journal |
J Appl Phys |
Volume |
119 |
Issue |
119 |
Pages |
093912 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
Using advanced Ginzburg-Landau simulations, we study the superconducting state of a thin superconducting film under a ferromagnetic layer, separated by an insulating oxide, in applied external magnetic field and electric current. The taken uniaxial ferromagnet is organized into a series of parallel domains with alternating polarization of out-of-plane magnetization, sufficiently strong to induce vortex-antivortex pairs in the underlying superconductor in absence of other magnetic field. We show the organization of such vortex-antivortex matter into rich configurations, some of which are not matching the periodicity of the ferromagnetic film. The variety of possible configurations is enhanced by applied homogeneous magnetic field, where additional vortices in the superconductor may lower the energy of the system by either annihilating the present antivortices under negative ferromagnetic domains or by lowering their own energy after positioning under positive ferromagnetic domains. As a consequence, both the vortex-antivortex reordering in increasing external field and the evolution of the energy of the system are highly nontrivial. Finally, we reveal the very interesting effects of applied dc electric current on the vortex-antivortex configurations, since resulting Lorentzian force has opposite direction for vortices and antivortices, while direction of the applied current with respect to ferromagnetic domains is of crucial importance for the interaction of the applied and the Meissner current, as well as the consequent vortex-antivortex dynamics-both of which are reflected in the anisotropic critical current of the system. (C) 2016 AIP Publishing LLC. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
American Institute of Physics |
Place of Publication |
New York, N.Y. |
Editor |
|
Language |
|
Wos |
000372351900018 |
Publication Date |
2016-03-07 |
Series Editor |
|
Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0021-8979; 1089-7550 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.068 |
Times cited |
4 |
Open Access |
|
Notes |
; This work was supported by the Brazilian agencies CNPq, PRONEX/FUNCAP, and CAPES, and the Research Foundation-Flanders (FWO). ; |
Approved |
Most recent IF: 2.068 |
Call Number |
UA @ lucian @ c:irua:133200 |
Serial |
4255 |
Permanent link to this record |
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|
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Author |
da Costa, D.R.; Zarenia, M.; Chaves, A.; Farias, G.A.; Peeters, F.M. |
Title |
Analytical study of the energy levels in bilayer graphene quantum dots |
Type |
A1 Journal article |
Year |
2014 |
Publication |
Carbon |
Abbreviated Journal |
Carbon |
Volume |
78 |
Issue |
|
Pages |
392-400 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
Using the four-band continuum model we derive a general expression for the infinite-mass boundary condition in bilayer graphene. Applying this new boundary condition we analytically calculate the confined states and the corresponding wave functions in a bilayer graphene quantum dot in the absence and presence of a perpendicular magnetic field. Our results for the energy spectrum show an energy gap between the electron and hole states at small magnetic fields. Furthermore the electron (e) and hole (h) energy levels corresponding to the K and K' valleys exhibit the E-K(e(h)) (m) = E-K'(e(h)) (m) symmetry, where m is the angular momentum quantum number. (C) 2014 Elsevier Ltd. All rights reserved. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Oxford |
Editor |
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Language |
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Wos |
000341463900042 |
Publication Date |
2014-07-16 |
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 |
|
ISSN |
0008-6223; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
6.337 |
Times cited |
35 |
Open Access |
|
Notes |
; This work was financially supported by CNPq, under contract NanoBioEstruturas 555183/2005-0, PRONEX/FUNCAP, CAPES Foundation under the process number BEX 7178/13-1, the Flemish Science Foundation (FWO-Vl), the European Science Foundation (ESF) under the EUROCORES program Euro-GRAPHENE (project CONGRAN), the Bilateral programme between CNPq and FWO-Vl, and the Brazilian Program Science Without Borders (CsF). We thank M. Ramezani Masir and M. Grujic for helpful comments and discussions. ; |
Approved |
Most recent IF: 6.337; 2014 IF: 6.196 |
Call Number |
UA @ lucian @ c:irua:119280 |
Serial |
109 |
Permanent link to this record |
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|
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Author |
da Costa; Zarenia, M.; Chaves, A.; Pereira, J.M., Jr.; Farias, G.A.; Peeters, F.M. |
Title |
Hexagonal-shaped monolayer-bilayer quantum disks in graphene : a tight-binding approach |
Type |
A1 Journal article |
Year |
2016 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
Volume |
94 |
Issue |
94 |
Pages |
035415 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
Using the tight-binding approach, we investigate confined states in two different hybrid monolayer-bilayer systems: (i) a hexagonal monolayer area surrounded by bilayer graphene in the presence of a perpendicularly applied electric field and (ii) a hexagonal bilayer graphene dot surrounded by monolayer graphene. The dependence of the energy levels on dot size and external magnetic field is calculated. We find that the energy spectrum for quantum dots with zigzag edges consists of states inside the gap which range from dot-localized states, edge states, to mixed states coexisting together, whereas for dots with armchair edges, only dot-localized states are observed. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000379502200008 |
Publication Date |
2016-07-11 |
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 |
|
ISSN |
2469-9950;2469-9969; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
11 |
Open Access |
|
Notes |
; This work was financially supported by CNPq, under contract NanoBioEstruturas No. 555183/2005-0, PRONEX/FUNCAP, CAPES Foundation, under the process No. BEX 7178/13-1, the Flemish Science Foundation (FWO-Vl), the Bilateral programme between CNPq and FWO-Vl, the Brazilian Program Science Without Borders (CsF), and the Lemann Foundation. ; |
Approved |
Most recent IF: 3.836 |
Call Number |
UA @ lucian @ c:irua:134947 |
Serial |
4190 |
Permanent link to this record |
|
|
|
Author |
da Costa, D.R.; Zarenia, M.; Chaves, A.; Farias, G.A.; Peeters, F.M. |
Title |
Magnetic field dependence of energy levels in biased bilayer graphene quantum dots |
Type |
A1 Journal article |
Year |
2016 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
Volume |
93 |
Issue |
93 |
Pages |
085401 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
Using the tight-binding approach, we study the influence of a perpendicular magnetic field on the energy levels of hexagonal, triangular, and circular bilayer graphene (BLG) quantum dots (QDs) with zigzag and armchair edges. We obtain the energy levels for AB (Bernal)-stacked BLG QDs in both the absence and the presence of a perpendicular electric field (i.e., biased BLG QDs). We find different regions in the spectrum of biased QDs with respect to the crossing point between the lowest-electron and -hole Landau levels of a biased BLG sheet. Those different regions correspond to electron states that are localized at the center, edge, or corner of the BLG QD. Quantum Hall corner states are found to be absent in circular BLG QDs. The spatial symmetry of the carrier density distribution is related to the symmetry of the confinement potential, the position of zigzag edges, and the presence or absence of interlayer inversion symmetry. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
|
Wos |
000369402400008 |
Publication Date |
2016-02-01 |
Series Editor |
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Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
2469-9950 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
22 |
Open Access |
|
Notes |
; This work was financially supported by CNPq, under Contract No. NanoBioEstruturas 555183/2005-0, PRONEX/FUNCAP, CAPES Foundation under the Process No. BEX 7178/13-1, the Flemish Science Foundation (FWO-Vl), the Bilateral programme between CNPq and FWO-Vl, and the Brazilian Program Science Without Borders (CsF). ; |
Approved |
Most recent IF: 3.836 |
Call Number |
c:irua:131623 |
Serial |
4038 |
Permanent link to this record |
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|
|
Author |
de Sena, S.H.R.; Pereira, J.M.; Peeters, F.M.; Farias, G.A. |
Title |
Topological confinement in trilayer graphene |
Type |
A1 Journal article |
Year |
2014 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
89 |
Issue |
3 |
Pages |
035420-35425 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
We calculate the spectrum of states that are localized at the interface between two regions of opposite bias in trilayer graphene (TLG). These potential profiles, also known as potential kinks, have been predicted to support two different branches of localized states for the case of bilayer graphene, and show similarities to the surface states of topological insulators. On the other hand, we found that ABC stacked TLG exhibits three different unidimensional branches of states in each valley that are confined to the kink interface. They have the property E(k(y)) = -E(-k(y)) when belonging to the same valley and E-K(k(y)) = -E-K' (-k(y)). A kink-antikink potential profile opens a gap in the spectrum of these one-dimensional states. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
|
Wos |
000332220800005 |
Publication Date |
2014-01-21 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
4 |
Open Access |
|
Notes |
; This work was supported by the Brazilian Council for Research (CNPq-PRONEX), the Flemish Science Foundation (FWO-Vl), and the Bilateral project between CNPq and FWO-Vl and the Brazilian program Science Without Borders (CsF). ; |
Approved |
Most recent IF: 3.836; 2014 IF: 3.736 |
Call Number |
UA @ lucian @ c:irua:115830 |
Serial |
3676 |
Permanent link to this record |
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|
Author |
Carvalho, J.C.N.; Ferreira, W.P.; Farias, G.A.; Peeters, F.M. |
Title |
Yukawa particles confined in a channel and subject to a periodic potential : ground state and normal modes |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
83 |
Issue |
9 |
Pages |
094109-094109,12 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
We consider a classical system of two-dimensional (2D) charged particles, interacting through a repulsive Yukawa potential exp(-r/λ)/r, and confined in a parabolic channel that limits the motion of the particles in the y direction. Along the x direction, the particles are subject to a periodic potential. The ground-state configurations and the normal-mode spectra of the system are obtained as a function of the periodicity and strength of the periodic potential (V0) and density. An interesting set of tunable ground-state configurations are found, with first- or second-order structural transitions between them. A configuration with particles aligned, perpendicular to the x direction, in each minimum of the periodic potential is obtained for V0 larger than some critical value that has a power-law dependence on the density. The phonon spectrum of different configurations was also calculated. A localization of the modes into a small frequency interval is observed for sufficiently large strength of the periodic potential, and a tunable gap in the phonon spectrum is found as a function of V0. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
|
Wos |
000288119700001 |
Publication Date |
2011-03-08 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
9 |
Open Access |
|
Notes |
; This work was supported by the Brazilian agencies CNPq and FUNCAP (PRONEX-Grant), and the bilateral projects between Flanders and Brazil and the Flemish Science Foundation (FWO-VI) and CNPq. ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
Call Number |
UA @ lucian @ c:irua:88779 |
Serial |
3928 |
Permanent link to this record |
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Author |
Chaves, A.; Komendová, L.; Milošević, M.V.; Andrade, J.S.; Farias, G.A.; Peeters, F.M. |
Title |
Conditions for nonmonotonic vortex interaction in two-band superconductors |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
83 |
Issue |
21 |
Pages |
214523-214523,6 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
We describe a semianalytic approach to the two-band Ginzburg-Landau theory, which predicts the behavior of vortices in two-band superconductors. We show that the character of the short-range vortex-vortex interaction is determined by the sign of the normal domain-superconductor interface energy, in analogy with the conventional differentiation between type I and type II superconductors. However, we also show that the long-range interaction is determined by a modified Ginzburg-Landau parameter κ*, different from the standard κ of a bulk superconductor. This opens the possibility for nonmonotonic vortex-vortex interaction, which is temperature dependent, and can be further tuned by alterations of the material on the microscopic scale. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000292252300009 |
Publication Date |
2011-06-30 |
Series Editor |
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Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
46 |
Open Access |
|
Notes |
; Discussions with A. Moreira, A. Shanenko, R. Prozorov, and A. Golubov are gratefully acknowledged. This work was supported by the Flemish Science Foundation (FWO-Vl), the Belgian Science Policy (IAP), the bilateral project FWO-CNPq, CAPES, and PRONEX/CNPq/FUNCAP. ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
Call Number |
UA @ lucian @ c:irua:90922 |
Serial |
477 |
Permanent link to this record |
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Author |
Xavier, L.J.P.; Pereira, J.M.; Chaves, A.; Farias, G.A.; Peeters, F.M. |
Title |
Topological confinement in graphene bilayer quantum rings |
Type |
A1 Journal article |
Year |
2010 |
Publication |
Applied physics letters |
Abbreviated Journal |
Appl Phys Lett |
Volume |
96 |
Issue |
21 |
Pages |
212108,1-212108,3 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
We find localized electron and hole states in a ring-shaped potential kink in biased bilayer graphene. Within the continuum description, we show that for sharp potential steps the Dirac equation describing carrier states close to the K (or K′) point of the first Brillouin zone can be solved analytically for a circular kink/antikink dot. The solutions exhibit interfacial states which exhibit AharonovBohm oscillations as functions of the height of the potential step and/or the radius of the ring. |
Address |
|
Corporate Author |
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Thesis |
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Publisher |
American Institute of Physics |
Place of Publication |
New York, N.Y. |
Editor |
|
Language |
|
Wos |
000278183200039 |
Publication Date |
2010-05-28 |
Series Editor |
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Series Title |
|
Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0003-6951; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.411 |
Times cited |
29 |
Open Access |
|
Notes |
; This work was financially supported by CNPq, under Contract No. NanoBioEstruturas 555183/2005-0, FUNCAP, CAPES, the Bilateral program between Flanders and Brazil, the Belgian Science Policy (IAP) and the Flemish Science Foundation (FWO-Vl). ; |
Approved |
Most recent IF: 3.411; 2010 IF: 3.841 |
Call Number |
UA @ lucian @ c:irua:83373 |
Serial |
3675 |
Permanent link to this record |