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Records |
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Author |
Muñoz, W.A.; Covaci, L.; Peeters, F.M. |
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Title |
Tight-binding study of bilayer graphene Josephson junctions |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
86 |
Issue |
18 |
Pages |
184505-184507 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Using highly efficient simulations of the tight-binding Bogoliubov-de-Gennes model, we solved self-consistently for the pair correlation and the Josephson current in a superconducting-bilayer graphene-superconducting Josephson junction. Different doping levels for the non-superconducting link are considered in the short- and long-junction regimes. Self-consistent results for the pair correlation and superconducting current resemble those reported previously for single-layer graphene except at the Dirac point, where remarkable differences in the proximity effect are found, as well as a suppression of the superconducting current in the long-junction regime. Inversion symmetry is broken by considering a potential difference between the layers and we found that the supercurrent can be switched if the junction length is larger than the Fermi length. |
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Wos  |
000310840400005 |
Publication Date |
2012-11-07 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
13 |
Open Access |
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Notes |
; This work was supported by the Flemish Science Foundation (FWO-VI). ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
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Call Number |
UA @ lucian @ c:irua:105149 |
Serial |
3661 |
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Author |
Müller, A.; Milošević, M.V.; Dale, S.E.C.; Engbarth, M.A.; Bending, S.J. |
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Title |
Magnetization measurements and Ginzburg-Landau simulations of micron-size \beta-tin samples : evidence for an unusual critical behavior of mesoscopic type-I superconductors |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Physical review letters |
Abbreviated Journal |
Phys Rev Lett |
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Volume |
109 |
Issue |
19 |
Pages |
197003 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We describe investigations of the largely unexplored field of mesoscopic type-I superconductors. Micromagnetometry and 3D Ginzburg-Landau simulations of our single crystal β-tin samples in this regime reveal size- and temperature-dependent supercritical fields whose behavior is radically different from the bulk critical field HcB. We find that complete suppression of the intermediate state in medium-size samples can result in a surprising reduction of the critical field significantly below HcB. We also reveal an evolution of the superconducting-to-normal phase transition from the expected irreversible first order at low temperatures through the previously unobserved reversible first-order to a second-order transition close to Tc, where the critical field can be many times larger than HcB. Finally, we have identified striking correlations between the mesoscopic Hc3 for nucleation of surface superconductivity and the thermodynamic Hc near Tc. All these observations are entirely unexpected in the conventional type-I picture. |
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Place of Publication |
New York, N.Y. |
Editor |
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Language |
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Wos |
000310853100017 |
Publication Date |
2012-11-09 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0031-9007;1079-7114; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
8.462 |
Times cited |
21 |
Open Access |
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Notes |
; This work was supported by the EPSRC-UK under Grant No. EP/E039944/1, and the Flemish Science Foundation (FWO). ; |
Approved |
Most recent IF: 8.462; 2012 IF: 7.943 |
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Call Number |
UA @ lucian @ c:irua:102401 |
Serial |
1893 |
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Author |
Saniz, R.; Xu, Y.; Matsubara, M.; Amini, M.N.; Dixit, H.; Lamoen, D.; Partoens, B. |
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Title |
A simplified approach to the band gap correction of defect formation energies : Al, Ga, and In-doped ZnO |
Type |
A1 Journal article |
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Year |
2013 |
Publication |
The journal of physics and chemistry of solids |
Abbreviated Journal |
J Phys Chem Solids |
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Volume |
74 |
Issue |
1 |
Pages |
45-50 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
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Abstract |
The calculation of defect levels in semiconductors within a density functional theory approach suffers greatly from the band gap problem. We propose a band gap correction scheme that is based on the separation of energy differences in electron addition and relaxation energies. We show that it can predict defect levels with a reasonable accuracy, particularly in the case of defects with conduction band character, and yet is simple and computationally economical. We apply this method to ZnO doped with group III elements (Al, Ga, In). As expected from experiment, the results indicate that Zn substitutional doping is preferred over interstitial doping in Al, Ga, and In-doped ZnO, under both zinc-rich and oxygen-rich conditions. Further, all three dopants act as shallow donors, with the +1 charge state having the most advantageous formation energy. Also, doping effects on the electronic structure of ZnO are sufficiently mild so as to affect little the fundamental band gap and lowest conduction bands dispersion, which secures their n-type transparent conducting behavior. A comparison with the extrapolation method based on LDA+U calculations and with the HeydScuseriaErnzerhof hybrid functional (HSE) shows the reliability of the proposed scheme in predicting the thermodynamic transition levels in shallow donor systems. |
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Place of Publication |
New York, N.Y. |
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Wos |
000311062500009 |
Publication Date |
2012-08-10 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0022-3697; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.059 |
Times cited |
36 |
Open Access |
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Notes |
Fwo; Bof-Nio |
Approved |
Most recent IF: 2.059; 2013 IF: 1.594 |
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Call Number |
UA @ lucian @ c:irua:101782 |
Serial |
3004 |
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Author |
Sels, D.; Brosens, F.; Magnus, W. |
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Title |
Wigner distribution functions for complex dynamical systems : a path integral approach |
Type |
A1 Journal article |
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Year |
2013 |
Publication |
Physica: A : theoretical and statistical physics |
Abbreviated Journal |
Physica A |
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Volume |
392 |
Issue |
2 |
Pages |
326-335 |
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Keywords |
A1 Journal article; Theory of quantum systems and complex systems; Condensed Matter Theory (CMT) |
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Abstract |
Starting from Feynmans Lagrangian description of quantum mechanics, we propose a method to construct explicitly the propagator for the Wigner distribution function of a single system. For general quadratic Lagrangians, only the classical phase space trajectory is found to contribute to the propagator. Inspired by Feynmans and Vernons influence functional theory we extend the method to calculate the propagator for the reduced Wigner function of a system of interest coupled to an external system. Explicit expressions are obtained when the external system consists of a set of independent harmonic oscillators. As an example we calculate the propagator for the reduced Wigner function associated with the CaldeiraLegett model. |
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Corporate Author |
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Place of Publication |
Amsterdam |
Editor |
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Language |
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Wos |
000311135200004 |
Publication Date |
2012-09-14 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0378-4371; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.243 |
Times cited |
9 |
Open Access |
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Notes |
; ; |
Approved |
Most recent IF: 2.243; 2013 IF: 1.722 |
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Call Number |
UA @ lucian @ c:irua:101414 |
Serial |
3921 |
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Author |
Croitoru, M.D.; Vagov, A.; Shanenko, A.A.; Axt, V.M. |
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Title |
The Cooper problem in nanoscale : enhancement of the coupling due to confinement |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Superconductor science and technology |
Abbreviated Journal |
Supercond Sci Tech |
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Volume |
25 |
Issue |
12 |
Pages |
124001-124005 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
In 1956 Cooper demonstrated (1956 Phys. Rev. 104 1189) that, no matter how weak the attraction is, two electrons in three-dimensional (3D) space just above the Fermi sea could be bound. In this work we investigate the influence of confinement on the binding energy of a Cooper pair. We show that confinement-induced modification of the Fermi sea results in a significant increase of the binding energy, when the bottom of an energy subband is very close to the Fermi surface. |
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Place of Publication |
Bristol |
Editor |
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Language |
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Wos |
000311418100004 |
Publication Date |
2012-11-08 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0953-2048;1361-6668; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.878 |
Times cited |
9 |
Open Access |
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Notes |
; MDC acknowledges support by the European Community under the Marie Curie IEF Action (Grant Agreement No. PIEF-GA-2009-235486-ScQSR). ; |
Approved |
Most recent IF: 2.878; 2012 IF: 2.758 |
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Call Number |
UA @ lucian @ c:irua:105121 |
Serial |
3573 |
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Author |
Sarmadian, N.; Saniz, R.; Lamoen, D.; Partoens, B. |
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Title |
Influence of Al concentration on the optoelectronic properties of Al-doped MgO |
Type |
A1 Journal article |
| |
Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
86 |
Issue |
20 |
Pages |
205129-5 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
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Abstract |
We use density functional theory within the local density approximation to investigate the structural, electronic, and optical properties of Al-doped MgO. The concentrations considered range from 6% to 56%. In the latter case, we also compare the optical properties of the amorphous and crystalline phases. We find that, overall, the electronic properties of the crystalline phases change qualitatively little with Al concentration. On the other hand, the changes in the electronic structure in the amorphous phase are more important, most notably because of deep impurity levels in the band gap that are absent in the crystalline phase. This leads to observable effects in, e.g., the optical absorption edge and in the refractive index. Thus, the latter can be used to characterize the crystalline to amorphous transition with Al doping level. |
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Wos |
000311605000003 |
Publication Date |
2012-11-28 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
5 |
Open Access |
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Notes |
Iwt; Fwo |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
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Call Number |
UA @ lucian @ c:irua:105137 |
Serial |
1612 |
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Author |
Beheshtian, J.; Sadeghi, A.; Neek-Amal, M.; Michel, K.H.; Peeters, F.M. |
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Title |
Induced polarization and electronic properties of carbon-doped boron nitride nanoribbons |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
86 |
Issue |
19 |
Pages |
195433-195438 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The electronic properties of boron nitride nanoribbons (BNNRs) doped with a line of carbon atoms are investigated using density functional calculations. By replacing a line of alternating B and N atoms with carbons, three different configurations are possible depending on the type of the atoms which bond to the carbons. We found very different electronic properties for these configurations: (i) the NCB arrangement is strongly polarized with a large dipole moment having an unexpected direction, (ii) the BCB and NCN arrangements are nonpolar with zero dipole moment, (iii) the doping by a carbon line reduces the band gap regardless of the local arrangement of the borons and the nitrogens around the carbon line, and (iv) the polarization and energy gap of the carbon-doped BNNRs can be tuned by an electric field applied parallel to the carbon line. Similar effects were found when either an armchair or zigzag line of carbon was introduced. |
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Place of Publication |
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Language |
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Wos |
000311694200006 |
Publication Date |
2012-11-29 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
41 |
Open Access |
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Notes |
; We would like to thank J. M. Pereira and S. Goedecker for helpful discussions. This work was supported by the Flemish Science Foundation (FWO-Vl), the ESF-EuroGRAPHENE project CONGRAN. M. N.-A is supported by EU-Marie Curie IIF postdoc Fellowship/299522. ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
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Call Number |
UA @ lucian @ c:irua:105136 |
Serial |
1603 |
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Author |
Van Duppen, B.; Peeters, F.M. |
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Title |
Comment on “Chiral tunneling in trilayer graphene” [Appl. Phys. Lett. 100, 163102 (2012)] |
Type |
Editorial |
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Year |
2012 |
Publication |
Applied physics letters |
Abbreviated Journal |
Appl Phys Lett |
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Volume |
101 |
Issue |
22 |
Pages |
226101-1 |
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Keywords |
Editorial; Condensed Matter Theory (CMT) |
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Abstract |
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Address |
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Publisher |
Amer inst physics |
Place of Publication |
Melville |
Editor |
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Language |
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Wos |
000311967000107 |
Publication Date |
2012-11-29 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0003-6951; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.411 |
Times cited |
7 |
Open Access |
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Notes |
; ; |
Approved |
Most recent IF: 3.411; 2012 IF: 3.794 |
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Call Number |
UA @ lucian @ c:irua:105999 |
Serial |
408 |
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Author |
de Sousa, J.S.; Covaci, L.; Peeters, F.M.; Farias, G.A. |
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Title |
Time-dependent investigation of charge injection in a quantum dot containing one electron |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Journal of applied physics |
Abbreviated Journal |
J Appl Phys |
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Volume |
112 |
Issue |
9 |
Pages |
093705-93709 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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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] |
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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 |
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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 |
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Impact Factor |
2.068 |
Times cited |
1 |
Open Access |
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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 |
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Call Number |
UA @ lucian @ c:irua:106014 |
Serial |
3664 |
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Author |
Berdiyorov, G.R.; Chao, X.H.; Peeters, F.M.; Wang, H.B.; Moshchalkov, V.V.; Zhu, B.Y. |
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Title |
Magnetoresistance oscillations in superconducting strips : a Ginzburg-Landau study |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
86 |
Issue |
22 |
Pages |
224504-224508 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Within the time-dependent Ginzburg-Landau theory we study the dynamic properties of current-carrying superconducting strips in the presence of a perpendicular magnetic field. We found pronounced voltage peaks as a function of the magnetic field, the amplitude of which depends both on sample dimensions and external parameters. These voltage oscillations are a consequence of moving vortices, which undergo alternating static and dynamic phases. At higher fields or for high currents, the continuous motion of vortices is responsible for the monotonic background on which the resistance oscillations due to the entry of additional vortices are superimposed. Mechanisms for such vortex-assisted resistance oscillations are discussed. Qualitative changes in the magnetoresistance curves are observed in the presence of random defects, which affect the dynamics of vortices in the system. |
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Corporate Author |
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Place of Publication |
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Language |
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Wos |
000312064300004 |
Publication Date |
2012-12-10 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
31 |
Open Access |
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Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl) and the ESF-NES program. G. R. B. acknowledges support from FWO-Vl. B.Y.Z. acknowledges the support from the MOST 973 Projects No. 2011CBA00110 and No. 2009CB930803, and the National Natural Science Foundation of China. V. V. M. acknowledges support from the Methusalem Funding by the Flemish Government. ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
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Call Number |
UA @ lucian @ c:irua:105969 |
Serial |
1930 |
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Author |
Michel, K.H.; Verberck, B. |
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Title |
Rigid-plane phonons in layered crystals |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Physica status solidi: B: basic research |
Abbreviated Journal |
Phys Status Solidi B |
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Volume |
249 |
Issue |
12 |
Pages |
2604-2607 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The determination of the layer number ${\cal N}$ in nanoscale thin layered crystals is a challenging problem of technological relevance. In addition to innovative experimental techniques, a thorough knowledge of the underlying lattice dynamics is required. Starting from phenomenological atomic interaction potentials we have carried out an analytical study of the low-frequency optical phonon dispersions in layered crystals. At the gamma point of the two-dimensional Brillouin zone the optical phonon frequencies correspond to rigid-plane shearing and compression modes. We have investigated graphene multilayers (GML) and hexagonal boron-nitride multilayers (BNML). The frequencies show a characteristic dependence on ${\cal N}$. The results which are represented in the form of fan diagrams are very similar for both materials. Due to charge neutrality within layers Coulomb forces play no role, only van der Waals forces between nearest neighbor layers are relevant. The theoretical results agree with recent low-frequency Raman results on rigid-layer modes [Tan et al., Nature Mater. 11, 294 (2012)] in GML and double-resonant Raman scattering data on rigid-layer compression modes [Herziger et al., Phys. Rev. B 85, 235447 (2012)] in GML. (C) 2012 WILEY-VCH Verlag GmbH Co. KGaA, Weinheim |
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Place of Publication |
Berlin |
Editor |
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Language |
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Wos |
000312215300072 |
Publication Date |
2012-11-19 |
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ISSN |
0370-1972; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
1.674 |
Times cited |
1 |
Open Access |
|
|
| |
Notes |
; This work has been supported by the Flemish Science Foundation (FWO-Vl) and the Bijzonder Onderzoeksfonds, Universiteit Antwerpen (BOF-UA). ; |
Approved |
Most recent IF: 1.674; 2012 IF: 1.489 |
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| |
Call Number |
UA @ lucian @ c:irua:105992 |
Serial |
2907 |
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| Permanent link to this record |
| |
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| |
|
Author |
Tyutyunnik, A.P.; Slobodin, B.V.; Samigullina, R.F.; Verberck, B.; Tarakina, N.V. |
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| |
Title |
K2CaV2O7 : a pyrovanadate with a new layered type of structure in the A2BV2O7 family |
Type |
A1 Journal article |
| |
Year |
2013 |
Publication |
Journal of the Chemical Society : Dalton transactions |
Abbreviated Journal |
Dalton T |
|
| |
Volume |
42 |
Issue |
4 |
Pages |
1057-1064 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
The crystal structure of K2CaV2O7 prepared by a conventional solid-state reaction has been solved by a direct method and refined using Rietveld full profile fitting based on X-ray powder diffraction data. This compound crystallises in the triclinic space group (P (1) over bar, Z = 2) with unit cell constants a = 7.1577(1) angstrom, b = 10.5104(2) angstrom, c = 5.8187(1) angstrom, alpha = 106.3368(9)degrees, beta = 106.235(1)degrees, gamma = 71.1375(9)degrees. The structure can be described as infinite undulating CaV2O72- layers parallel to the ac plane, which consist of pairs of edge-sharing CaO6 octahedra connected to each other through V2O7 pyrogroups. The potassium atoms are positioned in two sites between the layers, with a distorted IX-fold coordination of oxygen atoms. The chemical composition obtained from the structural solution was confirmed by energy-dispersive X-ray analysis. The stability of compounds in the family of alkali metal calcium pyrovanadates is discussed based on an analysis of the correlation between anion and cation sizes and theoretical first-principles calculations. |
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| |
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 |
|
Wos |
000312659200030 |
Publication Date |
2012-10-04 |
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| |
Series Editor |
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Series Title |
|
Abbreviated Series Title |
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| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1477-9226;1477-9234; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
4.029 |
Times cited |
3 |
Open Access |
|
|
| |
Notes |
; N.V.T. acknowledges funding by the Bavarian Ministry of Sciences, Research and the Arts. B. V. was financially supported by the Flemish Science Foundation (FWO-Vlaanderen). ; |
Approved |
Most recent IF: 4.029; 2013 IF: 4.097 |
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| |
Call Number |
UA @ lucian @ c:irua:105945 |
Serial |
3536 |
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| Permanent link to this record |
| |
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| |
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Author |
Varykhalov, A.; Marchenko, D.; Sanchez-Barriga, J.; Scholz, M.R.; Verberck, B.; Trauzettel, B.; Wehling, T.O.; Carbone, C.; Rader, O. |
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| |
Title |
Intact dirac cones at broken sublattice symmetry : photoemission study of graphene on Ni and Co |
Type |
A1 Journal article |
| |
Year |
2012 |
Publication |
Physical review X |
Abbreviated Journal |
Phys Rev X |
|
| |
Volume |
2 |
Issue |
4 |
Pages |
041017-10 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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| |
Abstract |
The appearance of massless Dirac fermions in graphene requires two equivalent carbon sublattices of trigonal shape. While the generation of an effective mass and a band gap at the Dirac point remains an unresolved problem for freestanding extended graphene, it is well established by breaking translational symmetry by confinement and by breaking sublattice symmetry by interaction with a substrate. One of the strongest sublattice-symmetry-breaking interactions with predicted and measured band gaps ranging from 400 meV to more than 3 eV has been attributed to the interfaces of graphene with Ni and Co, which are also promising spin-filter interfaces. Here, we apply angle-resolved photoemission to epitaxial graphene on Ni (111) and Co(0001) to show the presence of intact Dirac cones 2.8 eV below the Fermi level. Our results challenge the common belief that the breaking of sublattice symmetry by a substrate and the opening of the band gap at the Dirac energy are in a straightforward relation. A simple effective model of a biased bilayer structure composed of graphene and a sublattice-symmetry-broken layer, corroborated by density-functional-theory calculations, demonstrates the general validity of our conclusions. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
College Park, Md |
Editor |
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| |
Language |
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Wos |
000312703200001 |
Publication Date |
2012-12-22 |
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| |
Series Editor |
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Series Title |
|
Abbreviated Series Title |
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| |
Series Volume |
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Series Issue |
|
Edition |
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| |
ISSN |
2160-3308; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
12.789 |
Times cited |
86 |
Open Access |
|
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| |
Notes |
; A. V. acknowledges helpful discussions with N. Sandler. This work was supported by SPP 1459 of the Deutsche Forschungsgemeinschaft. B. V. acknowledges support from the Research Foundation Flanders (FWO-Vlaanderen). B. T. and T. O. W. would like to thank the KITP at Santa Barbara for hospitality during the completion of this work. ; |
Approved |
Most recent IF: 12.789; 2012 IF: 6.711 |
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| |
Call Number |
UA @ lucian @ c:irua:105964 |
Serial |
1677 |
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| Permanent link to this record |
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| |
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Author |
Zhu, J.; Badalyan, S.M.; Peeters, F.M. |
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| |
Title |
Electron-phonon bound states in graphene in a perpendicular magnetic field |
Type |
A1 Journal article |
| |
Year |
2012 |
Publication |
Physical review letters |
Abbreviated Journal |
Phys Rev Lett |
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| |
Volume |
109 |
Issue |
25 |
Pages |
256602-256605 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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| |
Abstract |
The spectrum of electron-phonon complexes in monolayer graphene is investigated in the presence of a perpendicular quantizing magnetic field. Despite the small electron-phonon coupling, usual perturbation theory is inapplicable for the calculation of the scattering amplitude near the threshold of optical phonon emission. Our findings, beyond perturbation theory, show that the true spectrum near the phonon-emission threshold is completely governed by new branches, corresponding to bound states of an electron and an optical phonon with a binding energy of the order of alpha omega(0), where alpha is the electron-phonon coupling and omega(0) the phonon energy. DOI: 10.1103/PhysRevLett.109.256602 |
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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 |
000312841700011 |
Publication Date |
2012-12-22 |
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| |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
|
Edition |
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| |
ISSN |
0031-9007;1079-7114; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
8.462 |
Times cited |
19 |
Open Access |
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| |
Notes |
; We acknowledge support from the Belgian Science Policy (BELSPO) and EU, the ESF EuroGRAPHENE project CONGRAN, and the Flemisch Science Foundation (FWO-Vl). ; |
Approved |
Most recent IF: 8.462; 2012 IF: 7.943 |
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| |
Call Number |
UA @ lucian @ c:irua:105962 |
Serial |
983 |
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| Permanent link to this record |
| |
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| |
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Author |
Geurts, R.; Milošević, M.V.; Albino Aguiar, J.; Peeters, F.M. |
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| |
Title |
Enhanced stability of vortex-antivortex states in two-component mesoscopic superconductors |
Type |
A1 Journal article |
| |
Year |
2013 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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| |
Volume |
87 |
Issue |
2 |
Pages |
024501-24508 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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| |
Abstract |
Using the Ginzburg-Landau (GL) theory, we calculate the stability of sample symmetry-induced vortex-antivortex molecules in a mesoscopic superconducting bilayer exposed to a homogeneous magnetic field. We demonstrate the conditions under which the two condensates cooperatively broaden the field-temperature stability range of the composite (joint) vortex-antivortex state. In cases when such broadening is not achieved, a reentrance of the vortex-antivortex state is found at lower temperatures. In a large portion of the phase diagram noncomposite states are possible, in which the antivortex is present in only one of the layers. In this case, we demonstrate that the vortex-antivortex molecule in one of the layers can be pinned and enlarged by interaction with a vortex molecule in the other. Using analogies in the respective GL formalisms, we map our findings for the bilayer onto mesoscopic two-band superconductors. |
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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 |
000313029800003 |
Publication Date |
2013-01-04 |
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| |
Series Editor |
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Series Title |
|
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 |
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| |
Impact Factor |
3.836 |
Times cited |
25 |
Open Access |
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| |
Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vlaanderen), the Brazilian science agencies FACEPE/CNPq under Grant No. APQ-0589-1.05/08 and CNPq under Grant No. 309832/2007-1, and the CNPq-FWO cooperation program under Grant No. 490681/2010-7. M.V.M. acknowledges support from the CAPES-PVE program. ; |
Approved |
Most recent IF: 3.836; 2013 IF: 3.664 |
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| |
Call Number |
UA @ lucian @ c:irua:105925 |
Serial |
1058 |
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| Permanent link to this record |
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| |
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Author |
Dixit, H.; Lamoen, D.; Partoens, B. |
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| |
Title |
Quasiparticle band structure of rocksalt-CdO determined using maximally localized Wannier functions |
Type |
A1 Journal article |
| |
Year |
2013 |
Publication |
Journal of physics : condensed matter |
Abbreviated Journal |
J Phys-Condens Mat |
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| |
Volume |
25 |
Issue |
3 |
Pages |
035501-35505 |
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| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
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| |
Abstract |
CdO in the rocksalt structure is an indirect band gap semiconductor. Thus, in order to determine its band gap one needs to calculate the complete band structure. However, in practice, the exact evaluation of the quasiparticle band structure for the large number of k-points which constitute the different symmetry lines in the Brillouin zone can be an extremely demanding task compared to the standard density functional theory (DFT) calculation. In this paper we report the full quasiparticle band structure of CdO using a plane-wave pseudopotential approach. In order to reduce the computational effort and time, we make use of maximally localized Wannier functions (MLWFs). The MLWFs offer a highly accurate method for interpolation of the DFT or GW band structure from a coarse k-point mesh in the irreducible Brillouin zone, resulting in a much reduced computational effort. The present paper discusses the technical details of the scheme along with the results obtained for the quasiparticle band gap and the electron effective mass. |
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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 |
000313100500010 |
Publication Date |
2012-12-12 |
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| |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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| |
Series Volume |
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Series Issue |
|
Edition |
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| |
ISSN |
0953-8984;1361-648X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
2.649 |
Times cited |
7 |
Open Access |
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| |
Notes |
Fwo |
Approved |
Most recent IF: 2.649; 2013 IF: 2.223 |
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| |
Call Number |
UA @ lucian @ c:irua:105296 |
Serial |
2801 |
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| Permanent link to this record |
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| |
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Author |
Xiao, Y.M.; Xu, W.; Zhang, Y.Y.; Peeters, F.M. |
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| |
Title |
Optoelectronic properties of ABC-stacked trilayer graphene |
Type |
A1 Journal article |
| |
Year |
2013 |
Publication |
Physica status solidi: B: basic research |
Abbreviated Journal |
Phys Status Solidi B |
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| |
Volume |
250 |
Issue |
1 |
Pages |
86-94 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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| |
Abstract |
We present a theoretical study on the optoelectronic properties of ABC-stacked trilayer graphene (TLG). The optical conductance and light transmittance are evaluated through using the energy-balance equation derived from the Boltzmann equation for an air/graphene/dielectric-wafer system in the presence of linearly polarized radiation field. The results obtained from two band structure models are examined and compared. For short wavelength radiation, the universal optical conductance sigma(0) = 3e(2)/(4h) can be obtained. Importantly, there exists an optical absorption window in the radiation wavelength range 10-200 mu m, which is induced by different transition energies required for inter- and intra-band optical absorption channels. As a result, we find that the position and width of this window depend sensitively on temperature and carrier density of the system, especially the lower frequency edge. There is a small characteristic absorption peak at about 82 mu m where the largest interband transition states exist in the ABC-stacked TLG model, in contrast to the relatively smooth curves in a simplified model. These theoretical results indicate that TLG has some interesting and important physical properties which can be utilized to realize infrared or THz optoelectronic devices. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Berlin |
Editor |
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| |
Language |
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Wos |
000313347500011 |
Publication Date |
2012-08-08 |
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| |
Series Editor |
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Series Title |
|
Abbreviated Series Title |
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| |
Series Volume |
|
Series Issue |
|
Edition |
|
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| |
ISSN |
0370-1972; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
1.674 |
Times cited |
6 |
Open Access |
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| |
Notes |
; This work was supported by the National Natural Science Foundation of China (grant no. 10974206), Department of Science and Technology of Yunnan Province, and by the Chinese Academy of Sciences. One of us (F.M.P.) was a Specially Appointed Foreign Professor of the Chinese Academy of Sciences. ; |
Approved |
Most recent IF: 1.674; 2013 IF: 1.605 |
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| |
Call Number |
UA @ lucian @ c:irua:110109 |
Serial |
2495 |
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| Permanent link to this record |
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Author |
Kapra, A.V.; Misko, V.R.; Peeters, F.M. |
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| |
Title |
Controlling magnetic flux motion by arrays of zigzag-arranged magnetic bars |
Type |
A1 Journal article |
| |
Year |
2013 |
Publication |
Superconductor science and technology |
Abbreviated Journal |
Supercond Sci Tech |
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| |
Volume |
26 |
Issue |
2 |
Pages |
025011-10 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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| |
Abstract |
Recent advances in manufacturing arrays of artificial pinning sites, i.e., antidots, blind holes and magnetic dots, allowed an effective control of magnetic flux in superconductors. An array of magnetic bars deposited on top of a superconducting film was shown to display different pinning regimes depending on the direction of the in-plane magnetization of the bars. Changing the sign of their magnetization results in changes in the induced magnetic pinning potentials. By numerically solving the time-dependent Ginzburg-Landau equations in a superconducting film with periodic arrays of zigzag-arranged magnetic bars, we revealed various flux dynamics regimes. In particular, we demonstrate flux pinning and flux flow, depending on the direction of the magnetization of the magnetic bars. Remarkably, the revealed different flux-motion regimes are associated with different mechanisms of vortex-antivortex dynamics. For example, we found that for an 'antiparallel' configuration of magnetic bars this dynamics involves a repeating vortex-antivortex generation and annihilation. We show that the depinning transition and the onset of flux flow can be manipulated by the magnetization of the bars and the geometry of the array. This provides an effective control of the depinning critical current that can be useful for possible fluxonics applications. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Bristol |
Editor |
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| |
Language |
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Wos |
000313559300011 |
Publication Date |
2012-12-20 |
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| |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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| |
Series Volume |
|
Series Issue |
|
Edition |
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| |
ISSN |
0953-2048;1361-6668; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
2.878 |
Times cited |
5 |
Open Access |
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| |
Notes |
; We acknowledge useful discussions with Denis Vodolazov and Alejandro Silhanek. This work was supported by the 'Odysseus' Program of the Flemish Government and the Flemish Science Foundation (FWO-Vl). ; |
Approved |
Most recent IF: 2.878; 2013 IF: 2.796 |
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| |
Call Number |
UA @ lucian @ c:irua:110080 |
Serial |
505 |
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| Permanent link to this record |
| |
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Author |
Carrillo-Nunez, H.; Magnus, W.; Vandenberghe, W.G.; Sorée, B.; Peeters, F.M. |
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| |
Title |
Phonon-assisted Zener tunneling in a p-n diode silicon nanowire |
Type |
A1 Journal article |
| |
Year |
2013 |
Publication |
Solid state electronics |
Abbreviated Journal |
Solid State Electron |
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| |
Volume |
79 |
Issue |
|
Pages |
196-200 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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| |
Abstract |
The Zener tunneling current flowing through a biased, abrupt p-n junction embedded in a cylindrical silicon nanowire is calculated. As the band gap becomes indirect for sufficiently thick wires, Zener tunneling and its related transitions between the valence and conduction bands are mediated by short-wavelength phonons interacting with mobile electrons. Therefore, not only the high electric field governing the electrons in the space-charge region but also the transverse acoustic (TA) and transverse optical (TO) phonons have to be incorporated in the expression for the tunneling current. The latter is also affected by carrier confinement in the radial direction and therefore we have solved the Schrodinger and Poisson equations self-consistently within the effective mass approximation for both conduction and valence band electrons. We predict that the tunneling current exhibits a pronounced dependence on the wire radius, particularly in the high-bias regime. (C) 2012 Elsevier Ltd. All rights reserved. |
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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 |
000313611000037 |
Publication Date |
2012-09-29 |
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| |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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| |
Series Volume |
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Series Issue |
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Edition |
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| |
ISSN |
0038-1101; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
1.58 |
Times cited |
2 |
Open Access |
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| |
Notes |
; This work is supported by the Flemish Science Foundation (FWO-VI), and the Interuniversity Attraction Poles, Belgium State, Belgium Science Policy, and IMEC. One of the authors (W. Vandenberghe) gratefully acknowledges the support of a Ph.D. stipend from the Institute for the Promotion of Innovation through Science and Technology in Flanders (IWT-Vlaanderen). ; |
Approved |
Most recent IF: 1.58; 2013 IF: 1.514 |
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| |
Call Number |
UA @ lucian @ c:irua:110104 |
Serial |
2600 |
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| Permanent link to this record |
| |
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Author |
Vandenberghe, W.G.; Verhulst, A.S.; Sorée, B.; Magnus, W.; Groeseneken, G.; Smets, Q.; Heyns, M.; Fischetti, M.V. |
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| |
Title |
Figure of merit for and identification of sub-60 mV/decade devices |
Type |
A1 Journal article |
| |
Year |
2013 |
Publication |
Applied physics letters |
Abbreviated Journal |
Appl Phys Lett |
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| |
Volume |
102 |
Issue |
1 |
Pages |
013510-13514 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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| |
Abstract |
A figure of merit I60 is proposed for sub-60 mV/decade devices as the highest current where the input characteristics exhibit a transition from sub- to super-60 mV/decade behavior. For sub-60 mV/decade devices to be competitive with metal-oxide-semiconductor field-effect devices, I60 has to be in the 1-10 μA/μm range. The best experimental tunnel field-effect transistors (TFETs) in the literature only have an I60 of 6×10-3 μA/μm but using theoretical simulations, we show that an I60 of up to 10 μA/μm should be attainable. It is proven that the Schottky barrier FET (SBFET) has a 60 mV/decade subthreshold swing limit while combining a SBFET and a TFET does improve performance. |
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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 |
000313646500132 |
Publication Date |
2013-01-12 |
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| |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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| |
Series Volume |
|
Series Issue |
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Edition |
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| |
ISSN |
0003-6951; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
3.411 |
Times cited |
64 |
Open Access |
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| |
Notes |
; William G. Vandenberghe gratefully acknowledges the support of a Ph.D. stipend from IWT-Vlaanderen. The authors thank Danielle Leonelli, Lars-Ake Ragnarsson, and Krishna Bhuwalka for useful discussions. This work was supported by imec's Industrial Affiliation Program. ; |
Approved |
Most recent IF: 3.411; 2013 IF: 3.515 |
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| |
Call Number |
UA @ lucian @ c:irua:109262 |
Serial |
1192 |
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| Permanent link to this record |
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Author |
Janyavula, S.; Lawson, N.; Çakir, D.; Beck, P.; Ramp, L.C.; Burgess, J.O. |
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| |
Title |
The wear of polished and glazed zirconia against enamel |
Type |
A1 Journal article |
| |
Year |
2013 |
Publication |
Journal Of Prosthetic Dentistry |
Abbreviated Journal |
J Prosthet Dent |
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| |
Volume |
109 |
Issue |
1 |
Pages |
22-29 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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| |
Abstract |
Statement of problem. The wear of tooth structure opposing anatomically contoured zirconia crowns requires further investigation. Purpose. The purpose of this in vitro study was to measure the roughness and wear of polished, glazed, and polished then reglazed zirconia against human enamel antagonists and compare the measurements to those of veneering porcelain and natural enamel. Material and methods. Zirconia specimens were divided into polished, glazed, and polished then reglazed groups (n=8). A veneering porcelain (Ceramco3) and enamel were used as controls. The surface roughness of all pretest specimens was measured. Wear testing was performed in the newly designed Alabama wear testing device. The mesiobuccal cusps of extracted molars were standardized and used as antagonists. Three-dimensional (3D) scans of the specimens and antagonists were obtained at baseline and after 200 000 and 400 000 cycles with a profilometer. The baseline scans were superimposed on the posttesting scans to determine volumetric wear. Data were analyzed with a 1-way ANOVA and Tukey Honestly Significant Difference (HSD) post hoc tests (alpha=.05) Results. Surface roughness ranked in order of least rough to roughest was: polished zirconia, glazed zirconia, polished then reglazed zirconia, veneering porcelain, and enamel. For ceramic, there was no measureable loss on polished zirconia, moderate loss on the surface of enamel, and significant loss on glazed and polished then reglazed zirconia. The highest ceramic wear was exhibited by the veneering ceramic. For enamel antagonists, polished zirconia caused the least wear, and enamel caused moderate wear. Glazed and polished then reglazed zirconia showed significant opposing enamel wear, and veneering porcelain demonstrated the most. Conclusions. Within the limitations of the study, polished zirconia is wear-friendly to the opposing tooth. Glazed zirconia causes more material and antagonist wear than polished zirconia. The surface roughness of the zirconia aided in predicting the wear of the opposing dentition. (J Prosthet Dent 2013;109:22-29) |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
St. Louis, Mo. |
Editor |
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Language |
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Wos |
000313934900004 |
Publication Date |
2013-01-15 |
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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 |
0022-3913 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.095 |
Times cited |
89 |
Open Access |
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Notes |
; ; |
Approved |
Most recent IF: 2.095; 2013 IF: 1.419 |
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Call Number |
UA @ lucian @ c:irua:128327 |
Serial |
4612 |
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| Permanent link to this record |
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Author |
Esfahani, D.N.; Covaci, L.; Peeters, F.M. |
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Title |
Field effect on surface states in a doped Mott-insulator thin film |
Type |
A1 Journal article |
| |
Year |
2013 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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| |
Volume |
87 |
Issue |
3 |
Pages |
035131-35136 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Surface effects of a doped thin film made of a strongly correlated material are investigated both in the absence and presence of a perpendicular electric field. We use an inhomogeneous Gutzwiller approximation for a single-band Hubbard model in order to describe correlation effects. For low doping, the bulk value of the quasiparticle weight is recovered exponentially deep into the slab, but with increasing doping, additional Friedel oscillations appear near the surface. We show that the inverse correlation length has a power-law dependence on the doping level. In the presence of an electrical field, considerable changes in the quasiparticle weight can be realized throughout the system. We observe a large difference (as large as five orders of magnitude) in the quasiparticle weight near the opposite sides of the slab. This effect can be significant in switching devices that use the surface states for transport. DOI: 10.1103/PhysRevB.87.035131 |
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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 |
000313941000001 |
Publication Date |
2013-01-29 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
4 |
Open Access |
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Notes |
; This work was supported by the Flemish Science Foundation (FWO-VI). ; |
Approved |
Most recent IF: 3.836; 2013 IF: 3.664 |
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Call Number |
UA @ lucian @ c:irua:110086 |
Serial |
1190 |
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| Permanent link to this record |
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Author |
Zarenia, M.; Pereira, J.M., Jr.; Peeters, F.M.; Farias, G.A. |
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Title |
Snake states in graphene quantum dots in the presence of a p-n junction |
Type |
A1 Journal article |
| |
Year |
2013 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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| |
Volume |
87 |
Issue |
3 |
Pages |
035426 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We investigate the magnetic interface states of graphene quantum dots that contain p-n junctions. Within a tight-binding approach, we consider rectangular quantum dots in the presence of a perpendicular magnetic field containing p-n as well as p-n-p and n-p-n junctions. The results show the interplay between the edge states associated with the zigzag terminations of the sample and the snake states that arise at the p-n junction due to the overlap between electron and hole states at the potential interface. Remarkable localized states are found at the crossing of the p-n junction with the zigzag edge having a dumb-bell-shaped electron distribution. The results are presented as a function of the junction parameters and the applied magnetic flux. DOI: 10.1103/PhysRevB.87.035426 |
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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 |
000313941000003 |
Publication Date |
2013-01-29 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
16 |
Open Access |
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Notes |
; This work was supported by the Flemish Science Foundation (FWO-VI), the European Science Foundation (ESF) under the EUROCORES program EuroGRAPHENE (project CONGRAN), the Brazilian agency CNPq (Pronex), and the bilateral projects between Flanders and Brazil and the collaboration project FWO-CNPq. ; |
Approved |
Most recent IF: 3.836; 2013 IF: 3.664 |
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Call Number |
UA @ lucian @ c:irua:110087 |
Serial |
3048 |
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| Permanent link to this record |
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Author |
Lucena, D.; Ferreira, W.P.; Munarin, F.F.; Farias, G.A.; Peeters, F.M. |
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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 |
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Volume |
87 |
Issue |
1 |
Pages |
012307-12309 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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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 |
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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 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1539-3755;1550-2376; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.366 |
Times cited |
11 |
Open Access |
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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 |
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Call Number |
UA @ lucian @ c:irua:110089 |
Serial |
3739 |
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| Permanent link to this record |
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Author |
Zhu, J.-J.; Badalyan, S.M.; Peeters, F.M. |
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Title |
Plasmonic excitations in Coulomb-coupled N-layer graphene structures |
Type |
A1 Journal article |
| |
Year |
2013 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
87 |
Issue |
8 |
Pages |
085401-85408 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We study Dirac plasmons and their damping in spatially separated N-layer graphene structures at finite doping and temperatures. The plasmon spectrum consists of one optical excitation with square-root dispersion and N – 1 acoustical excitations with linear dispersion, which are undamped at zero temperature and finite doping within a triangular energy region outside the electron-hole continuum. In the long-wavelength limit the energy and weight of the optical plasmon modes increase, respectively, as the square root and linearly with N in agreement with recent experimental findings. The energy and weight of the upper-lying acoustical branches also increase with N. This increase is strongest for the uppermost acoustical mode, and we find that its energy can exceed at some value of momentum the plasmon energy in an individual graphene sheet. Meanwhile, the energy of the low-lying acoustical branches decreases weakly with N as compared with the single acoustical mode in double-layer graphene structures. Our numerical calculations provide a detailed understanding of the overall behavior of the wave-vector dependence of the optical and acoustical multilayer plasmon modes and show how their dispersion and damping are modified as a function of temperature, interlayer spacing, and inlayer carrier density in (un)balanced graphene multilayer structures. DOI: 10.1103/PhysRevB.87.085401 |
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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 |
000314682900005 |
Publication Date |
2013-02-05 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
59 |
Open Access |
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Notes |
; This work was supported by the ESF-Eurocores program EuroGRAPHENE (CONGRAN project) and the Flemish Science Foundation (FWO-Vl). ; |
Approved |
Most recent IF: 3.836; 2013 IF: 3.664 |
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Call Number |
UA @ lucian @ c:irua:107671 |
Serial |
2645 |
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Author |
Villegas, C.E.P.; Tavares, M.R.S.; Hai, G.-Q.; Peeters, F.M. |
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Title |
Sorting the modes contributing to guidance in strain-induced graphene waveguides |
Type |
A1 Journal article |
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Year |
2013 |
Publication |
New journal of physics |
Abbreviated Journal |
New J Phys |
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Volume |
15 |
Issue |
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Pages |
023015-11 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We propose a simple way of probing the number of modes contributing to the channeling in graphene waveguides which are formed by a gauge potential produced by mechanical strain. The energy mode structure for both homogeneous and non-homogeneous strain regimes is carefully studied using the continuum description of the Dirac equation. We found that high strain values privilege negative (instead of positive) group velocities throughout the guidance, sorting the types of modes flowing through it. We also show how the effect of a substrate-induced gap competes against the strain. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Bristol |
Editor |
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Language |
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Wos |
000314868000002 |
Publication Date |
2013-02-08 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1367-2630; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.786 |
Times cited |
7 |
Open Access |
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Notes |
; This work was supported by FAPESP, CNPq and the Flemish Science Foundation (FWO-VI). ; |
Approved |
Most recent IF: 3.786; 2013 IF: 3.671 |
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Call Number |
UA @ lucian @ c:irua:107667 |
Serial |
3056 |
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Author |
Li, B.; Djotyan, A.P.; Hao, Y.L.; Avetisyan, A.A.; Peeters, F.M. |
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Title |
Effect of a perpendicular magnetic field on the shallow donor states near a semiconductor-metal interface |
Type |
A1 Journal article |
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Year |
2013 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
87 |
Issue |
7 |
Pages |
075313-75319 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We investigate the influence of an external perpendicular magnetic field on the lowest-energy states of an electron bound to a donor which is located near a semiconductor-metal interface. The problem is treated within the effective mass approach and the lowest-energy states are obtained through (1) the “numerically exact” finite element method, and (2) a variational approach using a trial wave function where all image charges that emerge due to the presence of the metallic gate are taken into account. The trial wave functions are constructed such that they reduce to an exponential behavior for sufficiently small magnetic fields and become Gaussian for intermediate and large magnetic fields. The average electron-donor distance can be controlled by the external magnetic field. We find that the size of the 2p(z) state depends strongly on the magnetic field when the donor is close to the interface, showing a nonmonotonic behavior, in contrast with the ground and the other excited states. DOI: 10.1103/PhysRevB.87.075313 |
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Place of Publication |
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Editor |
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Language |
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Wos |
000314874800017 |
Publication Date |
2013-02-13 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
1 |
Open Access |
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Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl). ; |
Approved |
Most recent IF: 3.836; 2013 IF: 3.664 |
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Call Number |
UA @ lucian @ c:irua:107664 |
Serial |
793 |
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Author |
Tran, T.L.A.; Çakir, D.; Wong, P.K.J.; Preobrajenski, A.B.; Brocks, G.; van der Wiel, W.G.; de Jong, M.P. |
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Title |
Magnetic properties of bcc-Fe(001)/C-60 interfaces for organic spintronics |
Type |
A1 Journal article |
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Year |
2013 |
Publication |
Acs Applied Materials & Interfaces |
Abbreviated Journal |
Acs Appl Mater Inter |
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Volume |
5 |
Issue |
3 |
Pages |
837-841 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The magnetic structure of the interfaces between organic semiconductors and ferromagnetic contacts plays a key role in the spin injection and extraction processes in organic spintronic devices. We present a combined computational (density functional theory) and experimental (X-ray magnetic circular dichroism) study on the magnetic properties of interfaces between bcc-Fe(001) and C-60 molecules. C-60 is an interesting candidate for application in organic spintronics due to the absence of hydrogen atoms and the associated hyperfine fields. Adsorption of C-60 on Fe(001) reduces the magnetic moments on the top Fe layers by similar to 6%, while inducing an antiparrallel magnetic moment of similar to-0.2 mu(B) on C-60. Adsorption of C-60 on a model ferromagnetic substrate consisting of three Fe monolayers on W(001) leads to a different structure but to very similar interface magnetic properties. |
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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 |
000315079700050 |
Publication Date |
2013-01-10 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1944-8244 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
7.504 |
Times cited |
28 |
Open Access |
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Notes |
; The authors acknowledge support from the European project MINOTOR (Grant No. FP7-NMP-228424), the European Research Council (ERC Starting Grant No. 280020), and the NWO VIDI program (Grant No. 10246). The use of supercomputer facilities was sponsored by the “Stichting Nationale Computerfaciliteiten (NCF)”, financially supported by the “Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)”. ; |
Approved |
Most recent IF: 7.504; 2013 IF: 5.900 |
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Call Number |
UA @ lucian @ c:irua:128326 |
Serial |
4599 |
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Author |
Sahin, H.; Peeters, F.M. |
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Title |
Adsorption of alkali, alkaline-earth, and 3d transition metal atoms on silicene |
Type |
A1 Journal article |
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Year |
2013 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
87 |
Issue |
8 |
Pages |
085423-85429 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The adsorption characteristics of alkali, alkaline-earth, and transition metal adatoms on silicene, a graphene-like monolayer structure of silicon are analyzed by means of first-principles calculations. In contrast to graphene, interaction between the metal atoms and the silicene surface is quite strong due to its highly reactive buckled hexagonal structure. In addition to structural properties, we also calculate the electronic band dispersion, net magnetic moment, charge transfer, work function, and dipole moment of the metal adsorbed silicene sheets. Alkali metals, Li, Na, and K, adsorb to hollow sites without any lattice distortion. As a consequence of the significant charge transfer from alkalis to silicene, metalization of silicene takes place. Trends directly related to atomic size, adsorption height, work function, and dipole moment of the silicene/alkali adatom system are also revealed. We found that the adsorption of alkaline-earth metals on silicene is entirely different from their adsorption on graphene. The adsorption of Be, Mg, and Ca turns silicene into a narrow gap semiconductor. Adsorption characteristics of eight transition metals Ti, V, Cr, Mn, Fe, Co, Mo, and W are also investigated. As a result of their partially occupied d orbital, transition metals show diverse structural, electronic, and magnetic properties. Upon the adsorption of transition metals, depending on the adatom type and atomic radius, the system can exhibit metal, half-metal, and semiconducting behavior. For all metal adsorbates, the direction of the charge transfer is from adsorbate to silicene, because of its high surface reactivity. Our results indicate that the reactive crystal structure of silicene provides a rich playground for functionalization at nanoscale. DOI: 10.1103/PhysRevB.87.085423 |
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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 |
000315146500008 |
Publication Date |
2013-02-19 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
281 |
Open Access |
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Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl). Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure). H.S. is supported by a FWO Pegasus Marie Curie Fellowship. ; |
Approved |
Most recent IF: 3.836; 2013 IF: 3.664 |
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Call Number |
UA @ lucian @ c:irua:107663 |
Serial |
62 |
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Author |
Grujić, M.; Tadić, M.; Peeters, F.M. |
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Title |
Antiferromagnetism in hexagonal graphene structures : rings versus dots |
Type |
A1 Journal article |
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Year |
2013 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
87 |
Issue |
8 |
Pages |
085434-85436 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Themean-field Hubbard model is used to investigate the formation of the antiferromagnetic phase in hexagonal graphene rings with inner zigzag edges. The outer edge of the ring was taken to be either zigzag or armchair, and we found that both types of structures can have a larger antiferromagnetic interaction as compared with hexagonal dots. This difference could be partially ascribed to the larger number of zigzag edges per unit area in rings than in dots. Furthermore, edge states localized on the inner ring edge are found to hybridize differently than the edge states of dots, which results in important differences in the magnetism of graphene rings and dots. The largest staggered magnetization is found when the outer edge has a zigzag shape. However, narrow rings with armchair outer edge are found to have larger staggered magnetization than zigzag hexagons. The edge defects are shown to have the least effect on magnetization when the outer ring edge is armchair shaped. DOI: 10.1103/PhysRevB.87.085434 |
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Place of Publication |
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Editor |
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Language |
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Wos |
000315146600005 |
Publication Date |
2013-02-20 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
29 |
Open Access |
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Notes |
; This work was supported by the EuroGRAPHENE programme of the ESF (project CONGRAN), the Serbian Ministry of Education, Science, and Technological Development, and the Flemish Science Foundation (FWO-VI). ; |
Approved |
Most recent IF: 3.836; 2013 IF: 3.664 |
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Call Number |
UA @ lucian @ c:irua:107661 |
Serial |
137 |
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| Permanent link to this record |
