| Records |
| Author |
Van Pottelberge, R.; Zarenia, M.; Vasilopoulos, P.; Peeters, F.M. |
| Title |
Graphene quantum dot with a Coulomb impurity : subcritical and supercritical regime |
Type  |
A1 Journal article |
| Year |
2017 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
| Volume |
95 |
Issue |
24 |
Pages |
245410 |
| Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
| Abstract |
We study the influence of confinement on the atomic collapse due to a Coulomb impurity placed at the center of a graphene quantum dot of radius R. We apply the zigzag or infinite-mass boundary condition and consider both a point-size and a finite-size impurity. As a function of the impurity strength Za, the energy spectra are discrete. In the case of the zigzag boundary condition, the degenerate (with respect to the angular momentum m) zero-energy levels are pulled down in energy as Z alpha increases, and they remain below epsilon = – Z alpha. Our results show that the energy levels exhibit a 1/R dependence in the subcritical regime [Z alpha < |km + 1/2|, k = 1 (-1) for the K (K') valley]. In the supercritical regime (Z alpha > |km + 1/2|) we find a qualitatively very different behavior where the levels decrease as a function of R in a nonmonotonic manner. While the valley symmetry is preserved in the presence of the impurity, we find that the impurity breaks electron-hole symmetry. We further study the energy spectrum of zigzag quantum dots in gapped graphene. Our results show that as the gap increases, the lowest electron states are pushed into the gap by the impurity. |
| 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 |
|
| Language |
|
Wos |
000403072400005 |
Publication Date |
2017-06-13 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
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| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
2469-9969; 2469-9950 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
3.836 |
Times cited |
13 |
Open Access |
|
| Notes |
; We thank Massoud Ramezani-Masir and Dean Moldovan for fruitful discussions. This work was supported by the Flemish Science Foundation (FWO-Vl), the Methusalem funding of the Flemish Government, and by the Canadian NSERC Grant No. OGP0121756 (P. V.). ; |
Approved |
Most recent IF: 3.836 |
| Call Number |
UA @ lucian @ c:irua:144197 |
Serial |
4661 |
| Permanent link to this record |
| |
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| |
| Author |
Mirzakhani, M.; Zarenia, M.; Vasilopoulos, P.; Ketabi, S.A.; Peeters, F.M. |
| Title |
Landau levels in biased graphene structures with monolayer-bilayer interfaces |
Type |
A1 Journal article |
| Year |
2017 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
| Volume |
96 |
Issue |
12 |
Pages |
125430 |
| Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
| Abstract |
The electron energy spectrum in monolayer-bilayer-monolayer and in bilayer-monolayer-bilayer graphene structures is investigated and the effects of a perpendicular magnetic field and electric bias are studied. Different types of monolayer-bilayer interfaces are considered as zigzag (ZZ) or armchair (AC) junctions which modify considerably the bulk Landau levels (LLs) when the spectra are plotted as a function of the center coordinate of the cyclotron orbit. Far away from the two interfaces, one obtains the well-known LLs for extended monolayer or bilayer graphene. The LL structure changes significantly at the two interfaces or junctions where the valley degeneracy is lifted for both types of junctions, especially when the distance between them is approximately equal to the magnetic length. Varying the nonuniform bias and the width of this junction-to-junction region in either structure strongly influence the resulting spectra. Significant differences exist between ZZ and AC junctions in both structures. The densities of states (DOSs) for unbiased structures are symmetric in energy whereas those for biased structures are asymmetric. An external bias creates interface LLs in the gaps between the LLs of the unbiased system in which the DOS can be quite small. Such a pattern of LLs can be probed by scanning tunneling microscopy. |
| 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 |
|
| Language |
|
Wos |
000411321800003 |
Publication Date |
2017-09-21 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
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| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
2469-9969; 2469-9950 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
3.836 |
Times cited |
6 |
Open Access |
|
| Notes |
; This work was supported by the BOF-UA (Bijzonder Onderzoeks Fonds), the Canadian NSERC through Grant No. OGP0121756 (P.V.), and the Methusalem Program of the Flemish Government. ; |
Approved |
Most recent IF: 3.836 |
| Call Number |
UA @ lucian @ c:irua:146746 |
Serial |
4787 |
| Permanent link to this record |
| |
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| |
| Author |
Mirzakhani, M.; Zarenia, M.; Vasilopoulos, P.; Peeters, F.M. |
| Title |
Electrostatically confined trilayer graphene quantum dots |
Type |
A1 Journal article |
| Year |
2017 |
Publication |
Physical review B |
Abbreviated Journal |
|
| Volume |
95 |
Issue |
15 |
Pages |
155434 |
| Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
| Abstract |
Electrically gating of trilayer graphene (TLG) opens a band gap offering the possibility to electrically engineer TLG quantum dots. We study the energy levels of such quantum dots and investigate their dependence on a perpendicular magnetic field B and different types of stacking of the graphene layers. The dots are modeled as circular and confined by a truncated parabolic potential which can be realized by nanostructured gates or position-dependent doping. The energy spectra exhibit the intervalley symmetry E-K(e) (m) = -E (h)(K') (m) for the electron (e) and hole (h) states, where m is the angular momentum quantum number and K and K' label the two valleys. The electron and hole spectra for B = 0 are twofold degenerate due to the intervalley symmetry E-K (m) = E-K' [-(m + 1)]. For both ABC [alpha = 1.5 (1.2) for large (small) R] and ABA (alpha = 1) stackings, the lowest-energy levels show approximately a R-alpha dependence on the dot radius R in contrast with the 1/R-3 one for ABC-stacked dots with infinite-mass boundary. As functions of the field B, the oscillator strengths for dipole-allowed transitions differ drastically for the two types of stackings. |
| 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 |
000399797200003 |
Publication Date |
2017-04-22 |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
|
Series Issue |
|
Edition |
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| ISSN |
2469-9969; 2469-9950 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
|
Times cited |
6 |
Open Access |
|
| Notes |
|
Approved |
no |
| Call Number |
UA @ admin @ c:irua:152652 |
Serial |
7878 |
| Permanent link to this record |
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| Author |
Pereira, J.M., Jr.; Mlinar, V.; Peeters, F.M.; Vasilopoulos, P. |
| Title |
Graphene-based quantum wires |
Type |
P1 Proceeding |
| Year |
2007 |
Publication |
AIP conference proceedings
T2 – 28th International Conference on the Physics of Semiconductors (ICPS-28), JUL 24-28, 2006, Vienna, AUSTRIA |
Abbreviated Journal |
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| Volume |
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Issue |
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Pages |
721-722 |
| Keywords |
P1 Proceeding; Condensed Matter Theory (CMT) |
| Abstract |
We investigate the properties of carriers in graphene-based quantum wires created by potential barriers, by means of analytical and numerical calculations. We obtain expressions for the energy spectrum as a function of barrier height, well width and linear momentum along the wire. The results demonstrate a direction-dependent resonant transmission across the potential well. |
| 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 |
Editor |
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| Language |
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Wos |
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Publication Date |
0000-00-00 |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
893 |
Series Issue |
|
Edition |
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| ISSN |
978-0-7354-0397-0; 0094-243x |
ISBN |
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Additional Links |
UA library record; WoS full record; |
| Impact Factor |
|
Times cited |
|
Open Access |
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| Notes |
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Approved |
Most recent IF: NA |
| Call Number |
UA @ lucian @ c:irua:103601 |
Serial |
1369 |
| Permanent link to this record |
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| |
| Author |
Zarenia, M.; Vasilopoulos, P.; Pourtolami, N.; Peeters, F.M. |
| Title |
Landau-level dispersion and the quantum Hall plateaus in bilayer graphene |
Type |
P1 Proceeding |
| Year |
2013 |
Publication |
AIP conference proceedings |
Abbreviated Journal |
|
| Volume |
1566 |
Issue |
|
Pages |
275-276 |
| Keywords |
P1 Proceeding; Condensed Matter Theory (CMT) |
| Abstract |
We study the quantum Hall effect (QHE) in bilayer graphene using the Kubo-Greenwood formula. At zero temperature the Hall conductivity sigma(yx) is given by sigma(yx) – 4(N + 1)e(2)/h with N the index of the highest occupied Landau level (LL). Including the dispersion of the LLs and their width, due to e. g. scattering by impurities, produces the plateau of the n = 0 LL in agreement with experimental results on doped samples and similar theoretical results on single-layer graphene plateaus widen with impurity concentration. Further, the evaluated resistivity rho(xx) exhibits a strong, oscillatory dependence on the electron concentration. Explicit results are obtained for delta-function impurities. |
| 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 |
Editor |
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| Language |
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Wos |
000331793000137 |
Publication Date |
2014-01-03 |
| 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 |
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ISBN |
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Additional Links |
UA library record; WoS full record |
| Impact Factor |
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Times cited |
|
Open Access |
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| Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl), the European Science Foundation (project CONGRAN) and the Canadian NSERC Grant No. OGP0121756. ; |
Approved |
Most recent IF: NA |
| Call Number |
UA @ lucian @ c:irua:115871 |
Serial |
1770 |
| Permanent link to this record |
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| Author |
Molnar, B.; Vasilopoulos, P.; Peeters, F.M. |
| Title |
Square-wave conductance through a chain of rings due to spin-orbit interaction |
Type |
P1 Proceeding |
| Year |
2005 |
Publication |
AIP conference proceedings |
Abbreviated Journal |
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| Volume |
772 |
Issue |
|
Pages |
1335-1336 |
| Keywords |
P1 Proceeding; Condensed Matter Theory (CMT) |
| Abstract |
We study ballistic electron transport through a finite chain of quantum circular rings in the presence of spin-orbit interaction (SOI) of strength alpha. The transmission and reflection coefficients for a single ring, obtained analytical lylead to the conductance for a chain of rings as a function of alpha and of the wave vector k of the incident electron. Due to destructive spin interferences the chain can be totaly opaque for certain ranges of k the width of which depends on the value of alpha. A periodic modulation of a widens up the gaps considerably and produces a nearly binary conductance output. |
| 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 |
Editor |
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| Language |
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Wos |
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Publication Date |
0000-00-00 |
| 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 |
0094-243x |
ISBN |
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Additional Links |
UA library record; WoS full record; |
| Impact Factor |
|
Times cited |
|
Open Access |
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| Notes |
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Approved |
Most recent IF: NA |
| Call Number |
UA @ lucian @ c:irua:94771 |
Serial |
3113 |
| Permanent link to this record |
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| Author |
Xu, W.; Vasilopoulos, P.; Das, M.P.; Peeters, F.M. |
| Title |
Self-consistent g* factor and spin-split Landau levels in strong magnetic fields and at low temperatures |
Type |
P3 Proceeding |
| Year |
1995 |
Publication |
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Abbreviated Journal |
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| Volume |
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Issue |
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Pages |
743-746 |
| Keywords |
P3 Proceeding; Condensed Matter Theory (CMT) |
| Abstract |
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| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
World Scientific |
Place of Publication |
Singapore |
Editor |
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| Language |
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Wos |
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Publication Date |
0000-00-00 |
| 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 |
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ISBN |
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Additional Links |
UA library record |
| Impact Factor |
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Times cited |
|
Open Access |
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| Notes |
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Approved |
MATERIALS SCIENCE, MULTIDISCIPLINARY 96/271 Q2 # |
| Call Number |
UA @ lucian @ c:irua:12203 |
Serial |
2974 |
| Permanent link to this record |
