Records |
Author |
Chen, Y.; Shanenko, A.A.; Peeters, F.M. |
Title |
Vortex anomaly in low-dimensional fermionic condensates : quantum confinement breaks chirality |
Type |
A1 Journal article |
Year |
2014 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
89 |
Issue |
5 |
Pages |
054513-54515 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
Chiral fermions are responsible for low-temperature properties of vortices in fermionic condensates, both superconducting (charged) and superfluid (neutral). One of the most striking consequences of this fact is that the core of a single-quantum vortex collapses at low temperatures, T -> 0 (i.e., the Kramer-Pesch effect for superconductors), due to the presence of chiral quasiparticles in the vortex-core region. We show that the situation changes drastically for fermionic condensates confined in quasi-one-dimensional and quasi-two-dimensional geometries. Here quantum confinement breaks the chirality of in-core fermions. As a result, instead of the ultimate shrinking, the core of a single-quantum vortex extends at low temperatures, and the condensate profile surprisingly mimics the multiquantum vortex behavior. Our findings are relevant for nanoscale superconductors, such as recent metallic nanoislands on silicon, and also for ultracold superfluid Fermi gases in cigar-shaped and pancake-shaped atomic traps. |
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Place of Publication |
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Language |
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Wos |
000332396800005 |
Publication Date |
2014-02-19 |
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 |
Impact Factor |
3.836 |
Times cited |
5 |
Open Access |
|
Notes |
; This work was supported by the “Odysseus” Program of the Flemish Government, the Flemish Science Foundation (FWO-Vl), the Methusalem Program, and the National Science Foundation of China under Grant No. NSFC-11304134. A. A. S. acknowledges the support of Brazilian agencies CNPq and FACEPE (Grant No. APQ-0589-1.05/08). ; |
Approved |
Most recent IF: 3.836; 2014 IF: 3.736 |
Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
UA @ lucian @ c:irua:115822 |
Serial |
3850 |
Permanent link to this record |
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Author |
Gou, H.; Tsirlin, A.A.; Bykova, E.; Abakumov, A.M.; Van Tendeloo, G.; Richter, A.; Ovsyannikov, S.V.; Kurnosov, A.V.; Trots, D.M.; Konôpková, Z.; Liermann, H.P.; Dubrovinsky, L.; Dubrovinskaia, N.; |
Title |
Peierls distortion, magnetism, and high hardness of manganese tetraboride |
Type |
A1 Journal article |
Year |
2014 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
89 |
Issue |
6 |
Pages |
064108-64109 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
We report crystal structure, electronic structure, and magnetism of manganese tetraboride, MnB4, synthesized under high-pressure, high-temperature conditions. In contrast to superconducting FeB4 and metallic CrB4, which are both orthorhombic, MnB4 features a monoclinic crystal structure. Its lower symmetry originates from a Peierls distortion of the Mn chains. This distortion nearly opens the gap at the Fermi level, but despite the strong dimerization and the proximity of MnB4 to the insulating state, we find indications for a sizable paramagnetic effective moment of about 1.7 mu(B)/f.u., ferromagnetic spin correlations, and, even more surprisingly, a prominent electronic contribution to the specific heat. However, no magnetic order has been observed in standard thermodynamic measurements down to 2 K. Altogether, this renders MnB4 a structurally simple but microscopically enigmatic material; we argue that its properties may be influenced by electronic correlations. |
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Corporate Author |
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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 |
000332405000002 |
Publication Date |
2014-02-24 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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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 |
Impact Factor |
3.836 |
Times cited |
39 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 3.836; 2014 IF: 3.736 |
Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
UA @ lucian @ c:irua:115819 |
Serial |
2571 |
Permanent link to this record |
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Author |
Govaerts, K.; Sluiter, M.H.F.; Partoens, B.; Lamoen, D. |
Title |
Homologous series of layered structures in binary and ternary Bi-Sb-Te-Se systems : ab initio study |
Type |
A1 Journal article |
Year |
2014 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
89 |
Issue |
5 |
Pages |
054106-54109 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
Abstract |
In order to account explicitly for the existence of long-periodic layered structures and the strong structural relaxations in the most common binary and ternary alloys of the Bi-Sb-Te-Se system, we have developed a one-dimensional cluster expansion (CE) based on first-principles electronic structure calculations, which accounts for the Bi and Sb bilayer formation. Excellent interlayer distances are obtained with a van der Waals density functional. It is shown that a CE solely based on pair interactions is sufficient to provide an accurate description of the ground-state energies of Bi-Sb-Te-Se binary and ternary systems without making the data set of ab initio calculated structures unreasonably large. For the binary alloys A1−xQx (A=Sb, Bi; Q=Te, Se), a ternary CE yields an almost continuous series of (meta)stable structures consisting of consecutive A bilayers next to consecutive A2Q3 for 0<x<0.6. For x>0.6, the binary alloy segregates into pure Q and A2Q3. The Bi-Sb system is described by a quaternary CE and is found to be an ideal solid solution stabilized by entropic effects at T≠0 K but with an ordered structure of alternating Bi and Sb layers for x=0.5 at T=0 K. A quintuple CE is used for the ternary Bi-Sb-Te system, where stable ternary layered compounds with an arbitrary stacking of Sb2Te3, Bi2Te3, and Te-Bi-Te-Sb-Te quintuple units are found, optionally separated by mixed Bi/Sb bilayers. Electronic properties of the stable compounds were studied taking spin-orbit coupling into account. |
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Thesis |
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Place of Publication |
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Language |
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Wos |
000332420900001 |
Publication Date |
2014-03-05 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
5 |
Open Access |
|
Notes |
Fwo; Hercules |
Approved |
Most recent IF: 3.836; 2014 IF: 3.736 |
Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
UA @ lucian @ c:irua:114910 |
Serial |
1487 |
Permanent link to this record |
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Author |
de Sousa, A.A.; Chaves, A.; Farias, G.A.; Peeters, F.M. |
Title |
Braess paradox at the mesoscopic scale |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
88 |
Issue |
24 |
Pages |
245417-6 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
We theoretically demonstrate that the transport inefficiency recently found experimentally for branched-out mesoscopic networks can also be observed in a quantum ring of finite width with an attached central horizontal branch. This is done by investigating the time evolution of an electron wave packet in such a system. Our numerical results show that the conductivity of the ring does not necessary improve if one adds an extra channel. This ensures that there exists a quantum analog of the Braess paradox, originating from quantum scattering and interference. |
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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 |
000328680500011 |
Publication Date |
2013-12-17 |
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 |
Impact Factor |
3.836 |
Times cited |
17 |
Open Access |
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Notes |
; This work was financially supported by PRONEX/CNPq/FUNCAP and the bilateral project CNPq-FWO. Discussions with J. S. Andrade, Jr. are gratefully acknowledged. A. A. S. has been financially supported by CAPES, under PDSE Contract No. BEX 7177/13-5. ; |
Approved |
Most recent IF: 3.836; 2013 IF: 3.664 |
Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
UA @ lucian @ c:irua:113705 |
Serial |
253 |
Permanent link to this record |
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Author |
Van Duppen, B.; Peeters, F.M. |
Title |
Thermodynamic properties of the electron gas in multilayer graphene in the presence of a perpendicular magnetic field |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
88 |
Issue |
24 |
Pages |
245429-7 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The thermodynamic properties of the electron gas in multilayer graphene depend strongly on the number of layers and the type of stacking. Here we analyze how those properties change when we vary the number of layers for rhombohedral stacked multilayer graphene and compare our results with those from a conventional two-dimensional electron gas. We show that the highly degenerate zero-energy Landau level which is partly filled with electrons and partly with holes has a strong influence on the values of the different thermodynamic quantities. |
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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 |
000328686900006 |
Publication Date |
2014-01-09 |
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 |
Impact Factor |
3.836 |
Times cited |
2 |
Open Access |
|
Notes |
; The authors would like to thank C. De Beule for enlightening discussions. This work was supported by the European Science Foundation (ESF) under the EUROCORES Program Euro-GRAPHENE within the project CONGRAN, the Flemish Science Foundation (FWO-Vl) by an aspirant research grant to B.V.D., and the Methusalem Program of the Flemish Government. ; |
Approved |
Most recent IF: 3.836; 2013 IF: 3.664 |
Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
UA @ lucian @ c:irua:113700 |
Serial |
3635 |
Permanent link to this record |
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Author |
Zarenia, M.; Partoens, B.; Chakraborty, T.; Peeters, F.M. |
Title |
Electron-electron interactions in bilayer graphene quantum dots |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
88 |
Issue |
24 |
Pages |
245432-245435 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
A parabolic quantum dot (QD) as realized by biasing nanostructured gates on bilayer graphene is investigated in the presence of electron-electron interaction. The energy spectrum and the phase diagram reveal unexpected transitions as a function of a magnetic field. For example, in contrast to semiconductor QDs, we find a valley transition rather than only the usual singlet-triplet transition in the ground state of the interacting system. The origin of these features can be traced to the valley degree of freedom in bilayer graphene. These transitions have important consequences for cyclotron resonance experiments. |
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 |
000328688600010 |
Publication Date |
2014-01-09 |
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 |
Impact Factor |
3.836 |
Times cited |
29 |
Open Access |
|
Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl), the European Science Foundation (ESF) under the EUROCORES program EuroGRAPHENE (project CONGRAN), and the Methusalem foundation of the Flemish Government. T. C. is supported by the Canada Research Chairs program of the Government of Canada. ; |
Approved |
Most recent IF: 3.836; 2013 IF: 3.664 |
Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
UA @ lucian @ c:irua:113698 |
Serial |
926 |
Permanent link to this record |
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Author |
Tan, H.; Egoavil, R.; Béché, A.; Martinez, G.T.; Van Aert, S.; Verbeeck, J.; Van Tendeloo, G.; Rotella, H.; Boullay, P.; Pautrat, A.; Prellier, W. |
Title |
Mapping electronic reconstruction at the metal-insulator interface in LaVO3/SrVO3 heterostructures |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
88 |
Issue |
15 |
Pages |
155123-155126 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
A (LaVO3)6/(SrVO3)(3) superlattice is studied with a combination of sub-A resolved scanning transmission electron microscopy and monochromated electron energy-loss spectroscopy. The V oxidation state is mapped with atomic spatial resolution enabling us to investigate electronic reconstruction at the LaVO3/SrVO3 interfaces. Surprisingly, asymmetric charge distribution is found at adjacent chemically symmetric interfaces. The local structure is proposed and simulated with a double channeling calculation which agrees qualitatively with our experiment. We demonstrate that local strain asymmetry is the likely cause of the electronic asymmetry of the interfaces. The electronic reconstruction at the interfaces extends much further than the chemical composition, varying from 0.5 to 1.2 nm. This distance corresponds to the length of charge transfer previously found in the (LaVO3)./(SrVO3). metal/insulating and the (LaAlO3)./(SrTiO3). insulating/insulating interfaces. |
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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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Language |
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Wos |
000326087100003 |
Publication Date |
2013-10-21 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
15 |
Open Access |
|
Notes |
Hercules; 246791 COUNTATOMS; 278510 VORTEX; 246102 IFOX; 312483 ESTEEM2; FWO; GOA XANES meets ELNES; esteem2jra3 ECASJO; |
Approved |
Most recent IF: 3.836; 2013 IF: 3.664 |
Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
UA @ lucian @ c:irua:112733UA @ admin @ c:irua:112733 |
Serial |
1944 |
Permanent link to this record |
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Author |
Shakouri, K.; Badalyan, S.M.; Peeters, F.M. |
Title |
Helical liquid of snake states |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
88 |
Issue |
19 |
Pages |
195404-195405 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
We derive an exact solution to the problem of spin snake states induced in a nonhomogeneous magnetic field by a combined action of the Rashba spin-orbit and Zeeman fields. The electron spin behavior as a function of the cyclotron orbit center position and an external homogeneous magnetic field was obtained. It is shown that in an antisymmetric magnetic field the electron spin in the snake states has only an in-plane projection, perpendicular to the magnetic interface, which vanishes at large positive momenta. Applying an external homogeneous magnetic field adds a finite out-of-plane spin component and simultaneously gaps out the spectral branches, which results in regular beating patterns of the spin current components. |
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 |
000326820200007 |
Publication Date |
2013-11-07 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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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 |
Impact Factor |
3.836 |
Times cited |
3 |
Open Access |
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Notes |
; This work was supported by the Methusalem program of the Flemish government and the Flemish Science Foundation (FWO-Vl). ; |
Approved |
Most recent IF: 3.836; 2013 IF: 3.664 |
Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
UA @ lucian @ c:irua:112712 |
Serial |
1416 |
Permanent link to this record |
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Author |
Badalyan, S.M.; Matos-Abiague, A.; Fabian, J.; Vignale, G.; Peeters, F.M. |
Title |
Spin-orbit-interaction induced singularity of the charge density relaxation propagator |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
88 |
Issue |
19 |
Pages |
195402-195405 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The charge density relaxation propagator of a two-dimensional electron system, which is the slope of the imaginary part of the polarization function, exhibits singularities for bosonic momenta having the order of the spin-orbit momentum and depending on the momentum orientation. We have provided an intuitive understanding for this nonanalytic behavior in terms of the interchirality subband electronic transitions, induced by the combined action of Bychkov-Rashba (BR) and Dresselhaus (D) spin-orbit coupling. It is shown that the regular behavior of the relaxation propagator is recovered in the presence of only one BR or D spin-orbit field or for spin-orbit interaction with equal BR and D coupling strengths. This creates a new possibility to influence carrier relaxation properties by means of an applied electric field. |
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 |
000326820200005 |
Publication Date |
2013-11-07 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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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 |
Impact Factor |
3.836 |
Times cited |
2 |
Open Access |
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Notes |
; We acknowledge support from the Methusalem program of the Flemish government and the Flemish Science Foundation (FWO-Vl), DFG SFB Grant 689, and NSF Grant DMR-1104788 (G.V.). ; |
Approved |
Most recent IF: 3.836; 2013 IF: 3.664 |
Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
UA @ lucian @ c:irua:112711 |
Serial |
3093 |
Permanent link to this record |
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Author |
Čukarić, N.A.; Tadić, M.Z.; Partoens, B.; Peeters, F.M. |
Title |
30-band k\cdot p model of electron and hole states in silicon quantum wells |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
88 |
Issue |
20 |
Pages |
205306 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
We modeled the electron and hole states in Si/SiO2 quantum wells within a basis of standing waves using the 30-band k . p theory. The hard-wall confinement potential is assumed, and the influence of the peculiar band structure of bulk silicon on the quantum-well sub-bands is explored. Numerous spurious solutions in the conduction-band and valence-band energy spectra are found and are identified to be of two types: (1) spurious states which have large contributions of the bulk solutions with large wave vectors (the high-k spurious solutions) and (2) states which originate mainly from the spurious valley outside the Brillouin zone (the extravalley spurious solutions). An algorithm to remove all those nonphysical solutions from the electron and hole energy spectra is proposed. Furthermore, slow and oscillatory convergence of the hole energy levels with the number of basis functions is found and is explained by the peculiar band mixing and the confinement in the considered quantum well. We discovered that assuming the hard-wall potential leads to numerical instability of the hole states computation. Nonetheless, allowing the envelope functions to exponentially decay in a barrier of finite height is found to improve the accuracy of the computed hole states. |
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Corporate Author |
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Publisher |
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Place of Publication |
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Language |
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Wos |
000327161500007 |
Publication Date |
2013-11-20 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
10 |
Open Access |
|
Notes |
; This work was supported by the Ministry of Education, Science, and Technological Development of Serbia, the Belgian Science Policy (IAP), the Flemish fund for Scientific Research (FWO-Vl), and the Methusalem programme of the Flemish government. ; |
Approved |
Most recent IF: 3.836; 2013 IF: 3.664 |
Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
UA @ lucian @ c:irua:112704 |
Serial |
18 |
Permanent link to this record |
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Author |
Krstajie, P.M.; Peeters, F.M. |
Title |
Energy-momentum dispersion relation of plasmarons in bilayer graphene |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
88 |
Issue |
16 |
Pages |
165420-165424 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The relation between the energy and momentum of plasmarons in bilayer graphene is investigated within the Overhauser approach, where the electron-plasmon interaction is described as a field theoretical problem. We find that the Dirac-like spectrum is shifted by Delta E(k) similar to 100 divided by 150 meV depending on the electron concentration n(e) and electron momentum. The shift increases with electron concentration as the energy of plasmons becomes larger. The dispersion of plasmarons is more pronounced than in the case of single layer graphene, which is explained by the fact that the energy dispersion of electrons is quadratic and not linear. We expect that these predictions can be verified using angle-resolved photoemission spectroscopy (ARPES). |
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Corporate Author |
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Publisher |
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Place of Publication |
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Language |
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Wos |
000326089400004 |
Publication Date |
2013-10-22 |
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 |
Impact Factor |
3.836 |
Times cited |
3 |
Open Access |
|
Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl), the ESF-EuroGRAPHENE project CON-GRAN, and by the Serbian Ministry of Education and Science, within the Project No. TR 32008. ; |
Approved |
Most recent IF: 3.836; 2013 IF: 3.664 |
Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
UA @ lucian @ c:irua:112224 |
Serial |
1042 |
Permanent link to this record |
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Author |
Neek-Amal, M.; Covaci, L.; Shakouri, K.; Peeters, F.M. |
Title |
Electronic structure of a hexagonal graphene flake subjected to triaxial stress |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
88 |
Issue |
11 |
Pages |
115428 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The electronic properties of a triaxially strained hexagonal graphene flake with either armchair or zigzag edges are investigated using molecular dynamics simulations and tight-binding calculations. We found that (i) the pseudomagnetic field in strained graphene flakes is not uniform neither in the center nor at the edge of zigzag terminated flakes, (ii) the pseudomagnetic field is almost zero in the center of armchair terminated flakes but increases dramatically near the edges, (iii) the pseudomagnetic field increases linearly with strain, for strains lower than 15% but increases nonlinearly beyond it, (iv) the local density of states in the center of the zigzag hexagon exhibits pseudo-Landau levels with broken sublattice symmetry in the zeroth pseudo-Landau level, and in addition there is a shift in the Dirac cone due to strain induced scalar potentials, and (v) there is size effect in pseudomagnetic field. This study provides a realistic model of the electronic properties of inhomogeneously strained graphene where the relaxation of the atomic positions is correctly included together with strain induced modifications of the hopping terms up to next-nearest neighbors. |
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 |
000324690400008 |
Publication Date |
2013-09-24 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
46 |
Open Access |
|
Notes |
; This work was supported by the EU-Marie Curie IIF postdoctoral Fellowship/ 299855 (for M.N.-A.), the ESF EuroGRAPHENE project CONGRAN, the Flemish Science Foundation (FWO-Vl) and the Methusalem Funding of the Flemish government. ; |
Approved |
Most recent IF: 3.836; 2013 IF: 3.664 |
Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
UA @ lucian @ c:irua:111168 |
Serial |
1011 |
Permanent link to this record |
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Author |
Komendová, L.; Milošević, M.V.; Peeters, F.M. |
Title |
Soft vortex matter in a type-I/type-II superconducting bilayer |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
88 |
Issue |
9 |
Pages |
094515 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
Magnetic flux patterns are known to strongly differ in the intermediate state of type-I and type-II superconductors. Using a type-I/type-II bilayer we demonstrate hybridization of these flux phases into a plethora of unique new ones. Owing to a complicated multibody interaction between individual fluxoids, many different intriguing patterns are possible under applied magnetic field, such as few-vortex clusters, vortex chains, mazes, or labyrinthal structures resembling the phenomena readily encountered in soft-matter physics. However, in our system the patterns are tunable by sample parameters, magnetic field, current, and temperature, which reveals transitions from short-range clustering to long-range ordered phases such as parallel chains, gels, glasses, and crystalline vortex lattices, or phases where lamellar type-I flux domains in one layer serve as a bedding potential for type-II vortices in the other, configurations clearly beyond the soft-matter analogy. |
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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 |
000324689900008 |
Publication Date |
2013-09-24 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
|
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
27 |
Open Access |
|
Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl). Insightful discussions with Arkady Shanenko and Edith Cristina Euan Diaz are gratefully acknowledged. ; |
Approved |
Most recent IF: 3.836; 2013 IF: 3.664 |
Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
UA @ lucian @ c:irua:111167 |
Serial |
3050 |
Permanent link to this record |
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|
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Author |
Zhang, L.-F.; Covaci, L.; Milošević, M.V.; Berdiyorov, G.R.; Peeters, F.M. |
Title |
Vortex states in nanoscale superconducting squares : the influence of quantum confinement |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
88 |
Issue |
14 |
Pages |
144501 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
Bogoliubov-de Gennes theory is used to investigate the effect of the size of a superconducting square on the vortex states in the quantum confinement regime. When the superconducting coherence length is comparable to the Fermi wavelength, the shape resonances of the superconducting order parameter have strong influence on the vortex configuration. Several unconventional vortex states, including asymmetric ones, giant-multivortex combinations, and states comprising giant antivortices, were found as ground states and their stability was found to be very sensitive on the value of k(F)xi(0), the size of the sample W, and the magnetic flux Phi. By increasing the temperature and/or enlarging the size of the sample, quantum confinement is suppressed and the conventional mesoscopic vortex states as predicted by the Ginzburg-Laudau (GL) theory are recovered. However, contrary to the GL results we found that the states containing symmetry-induced vortex-antivortex pairs are stable over the whole temperature range. It turns out that the inhomogeneous order parameter induced by quantum confinement favors vortex-antivortex molecules, as well as giant vortices with a rich structure in the vortex core-unattainable in the GL domain. |
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 |
000325498300004 |
Publication Date |
2013-10-09 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
19 |
Open Access |
|
Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vlaanderen) and Methusalem Funding of the Flemish government. ; |
Approved |
Most recent IF: 3.836; 2013 IF: 3.664 |
Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
UA @ lucian @ c:irua:111145 |
Serial |
3891 |
Permanent link to this record |
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Author |
Turner, S.; Shenderova, O.; da Pieve, F.; Lu, Y.-G.; Yücelen, E.; Verbeeck, J.; Lamoen, D.; Van Tendeloo, G. |
Title |
Aberration-corrected microscopy and spectroscopy analysis of pristine, nitrogen containing detonation nanodiamond |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Physica status solidi : A : applications and materials science |
Abbreviated Journal |
Phys Status Solidi A |
Volume |
210 |
Issue |
10 |
Pages |
1976-1984 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Aberration-corrected transmission electron microscopy, electron energy-loss spectroscopy, and density functional theory (DFT) calculations are used to solve several key questions about the surface structure, the particle morphology, and the distribution and nature of nitrogen impurities in detonation nanodiamond (DND) cleaned by a recently developed ozone treatment. All microscopy and spectroscopy measurements are performed at a lowered acceleration voltage (80/120kV), allowing prolonged and detailed experiments to be carried out while minimizing the risk of knock-on damage or surface graphitization of the nanodiamond. High-resolution TEM (HRTEM) demonstrates the stability of even the smallest nanodiamonds under electron illumination at low voltage and is used to image the surface structure of pristine DND. High resolution electron energy-loss spectroscopy (EELS) measurements on the fine structure of the carbon K-edge of nanodiamond demonstrate that the typical * pre-peak in fact consists of three sub-peaks that arise from the presence of, amongst others, minimal fullerene-like reconstructions at the nanoparticle surfaces and deviations from perfect sp(3) coordination at defects in the nanodiamonds. Spatially resolved EELS experiments evidence the presence of nitrogen within the core of DND particles. The nitrogen is present throughout the whole diamond core, and can be enriched at defect regions. By comparing the fine structure of the experimental nitrogen K-edge with calculated energy-loss near-edge structure (ELNES) spectra from DFT, the embedded nitrogen is most likely related to small amounts of single substitutional and/or A-center nitrogen, combined with larger nitrogen clusters. |
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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Language |
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Wos |
000329299700025 |
Publication Date |
2013-10-18 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
|
ISSN |
1862-6300; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
1.775 |
Times cited |
37 |
Open Access |
|
Notes |
262348 ESMI; 246791 COUNTATOMS; FWO; Hercules; GOA XANES meets ELNES |
Approved |
Most recent IF: 1.775; 2013 IF: 1.525 |
Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
UA @ lucian @ c:irua:110821UA @ admin @ c:irua:110821 |
Serial |
41 |
Permanent link to this record |
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Author |
Shakouri, K.; Masir, M.R.; Jellal, A.; Choubabi, E.B.; Peeters, F.M. |
Title |
Effect of spin-orbit couplings in graphene with and without potential modulation |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
88 |
Issue |
11 |
Pages |
115408-115409 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
We investigate the effect of Rashba and intrinsic spin-orbit couplings on the electronic properties and spin configurations of Dirac fermions confined in: (i) a flat graphene sheet, (ii) a graphene wire with p-n-p structure, and (iii) a superlattice of graphene wires. The interplay between the spin-orbit interaction mechanisms breaks the electron-hole symmetry and the spin configuration induced by Rashba spin-orbit coupling lacks inversion symmetry in k space. We show that the Rashba spin-orbit interaction doubles the Fabry-Perot resonant modes in the transmission spectrum of a graphene wire and opens new channels for the electron transmission. Moreover, it leads to the appearance of spin split extra Dirac cones in the energy spectrum of a graphene superlattice. It is shown that the spin of the electrons and holes confined in a flat graphene sheet is always perpendicular to their motion while this is not the case for the other nanostructures. |
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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 |
000323944600005 |
Publication Date |
2013-09-05 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
36 |
Open Access |
|
Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl) and the European Science Foundation (ESF) under the EUROCORES Program EuroGRAPHENE within the project CONGRAN. The generous support provided by the Saudi Center for Theoretical Physics (SCTP) is highly appreciated by A.J. and E.B.C. They also thank the Deanship of Scientific Research at King Faisal University for funding this work under the Project No. 130193. ; |
Approved |
Most recent IF: 3.836; 2013 IF: 3.664 |
Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
UA @ lucian @ c:irua:110716 |
Serial |
836 |
Permanent link to this record |
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Author |
Zarenia, M.; Pereira, J.M., Jr.; Peeters, F.M.; Farias, G.A. |
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 |
Volume |
87 |
Issue |
3 |
Pages |
035426 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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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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 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
16 |
Open Access |
|
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 |
Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
UA @ lucian @ c:irua:110087 |
Serial |
3048 |
Permanent link to this record |
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Author |
Esfahani, D.N.; Covaci, L.; Peeters, F.M. |
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 |
Volume |
87 |
Issue |
3 |
Pages |
035131-35136 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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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Place of Publication |
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Language |
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Wos |
000313941000001 |
Publication Date |
2013-01-29 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
4 |
Open Access |
|
Notes |
; This work was supported by the Flemish Science Foundation (FWO-VI). ; |
Approved |
Most recent IF: 3.836; 2013 IF: 3.664 |
Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
UA @ lucian @ c:irua:110086 |
Serial |
1190 |
Permanent link to this record |
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Author |
Dixit, H.; Tandon, N.; Cottenier, S.; Saniz, R.; Lamoen, D.; Partoens, B. |
Title |
Erratum : First-principles study of possible shallow donors in ZnAl2O4 spinel [Phys. Rev. B 87, 174101 (2013)] |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
88 |
Issue |
5 |
Pages |
059905-2 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
Abstract |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Wos |
000323572600009 |
Publication Date |
2013-08-27 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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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 |
Impact Factor |
3.836 |
Times cited |
1 |
Open Access |
|
Notes |
; ; |
Approved |
Most recent IF: 3.836; 2013 IF: 3.664 |
Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
UA @ lucian @ c:irua:110015 |
Serial |
1080 |
Permanent link to this record |
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Author |
Leenaerts, O.; Sahin, H.; Partoens, B.; Peeters, F.M. |
Title |
First-principles investigation of B- and N-doped fluorographene |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
88 |
Issue |
3 |
Pages |
035434-35435 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The effect of substitutional doping of fluorographene with boron and nitrogen atoms on its electronic and magnetic properties is investigated using first-principles calculations. It is found that boron dopants can be readily incorporated in the fluorographene crystal where they act as shallow acceptors and cause hole doping, but no changes in the magnetic properties are observed. Nitrogen dopants act as deep donors and give rise to a magnetic moment, but the resulting system becomes chemically unstable. These results are opposite to what was found for substitutional doping of graphane, i.e., hydrogenated graphene, in which case B substituents induce magnetism and N dopants do not. |
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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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Wos |
000322083700002 |
Publication Date |
2013-07-22 |
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 |
Impact Factor |
3.836 |
Times cited |
16 |
Open Access |
|
Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Methusalem program of the Flemish government. H.S. is supported by a FWO Pegasus-long Marie Curie Fellowship. Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure), and the HPC infrastructure of the University of Antwerp (CalcUA), a division of the Flemish Supercomputer Center VSC. ; |
Approved |
Most recent IF: 3.836; 2013 IF: 3.664 |
Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
UA @ lucian @ c:irua:109807 |
Serial |
1210 |
Permanent link to this record |
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Author |
Sahin, H.; Sivek, J.; Li, S.; Partoens, B.; Peeters, F.M. |
Title |
Stone-Wales defects in silicene : formation, stability, and reactivity of defect sites |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
88 |
Issue |
4 |
Pages |
045434-45436 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
During the synthesis of ultrathin materials with hexagonal lattice structure Stone-Wales (SW) type of defects are quite likely to be formed and the existence of such topological defects in the graphenelike structures results in dramatic changes of their electronic and mechanical properties. Here we investigate the formation and reactivity of such SW defects in silicene. We report the energy barrier for the formation of SW defects in freestanding (similar to 2.4 eV) and Ag(111)-supported (similar to 2.8 eV) silicene and found it to be significantly lower than in graphene (similar to 9.2 eV). Moreover, the buckled nature of silicene provides a large energy barrier for the healing of the SW defect and therefore defective silicene is stable even at high temperatures. Silicene with SW defects is semiconducting with a direct band gap of 0.02 eV and this value depends on the concentration of defects. Furthermore, nitrogen substitution in SW-defected silicene shows that the defect lattice sites are the least preferable substitution locations for the N atoms. Our findings show the easy formation of SW defects in silicene and also provide a guideline for band gap engineering in silicene-based materials through such defects. |
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 |
000322113300007 |
Publication Date |
2013-07-23 |
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 |
Impact Factor |
3.836 |
Times cited |
93 |
Open Access |
|
Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Methusalem foundation of the Flemish government. Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure), and HPC infrastructure of the University of Antwerp (CalcUA) a division of the Flemish Supercomputer Center (VSC), which is funded by the Hercules foundation. H.S. is supported by a FWO Pegasus Marie Curie Fellowship. ; |
Approved |
Most recent IF: 3.836; 2013 IF: 3.664 |
Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
UA @ lucian @ c:irua:109805 |
Serial |
3162 |
Permanent link to this record |
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Author |
Couet, S.; Peelaers, H.; Trekels, M.; Houben, K.; Petermann, C.; Hu, M.Y.; Zhao, J.Y.; Bi, W.; Alp, E.E.; Menéndez, E.; Partoens, B.; Peeters, F.M.; Van Bael, M.J.; Vantomme, A.; Temst, K.; |
Title |
Interplay between lattice dynamics and superconductivity in Nb3Sn thin films |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
88 |
Issue |
4 |
Pages |
045437-7 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
We investigate the link between superconductivity and atomic vibrations in Nb3Sn films with a thickness ranging from 10 to 50 nm. The challenge of measuring the phonon density of states (PDOS) of these films has been tackled by employing the technique of nuclear inelastic scattering by Sn-119 isotopes to reveal the Sn-partial phonon density of states. With the support of ab initio calculations, we evaluate the effect of reduced film thickness on the PDOS. This approach allows us to estimate the changes in superconducting critical temperature T-c induced by phonon confinement, which turned out to be limited to a few tenths of K. The presented method is successful for the Nb3Sn system and paves the way for more systematic studies of the role of phonon confinement in Sn-containing superconductors. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000322529900004 |
Publication Date |
2013-07-27 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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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 |
Impact Factor |
3.836 |
Times cited |
5 |
Open Access |
|
Notes |
; The authors would like to cordially thank Dr. Rudolf Ruffer from the nuclear resonant scattering group of the ESRF for the support and gratefully acknowledge the ESRF for providing beamtime for the preliminary phonon study. S. C., K. H., and E. M. thank the Flemish Science Foundation (FWO-Vl) for their personal fellowship. This work was supported by FWO-Vl, the Methusalem program of the Flemish government, and the Concerted Research Action program (GOA/09/ 006) and (GOA/14/007). Use of the Advanced Photon Source, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science by Argonne National Laboratory, was supported by the U.S. DOE under Contract No. DE-AC02-06CH11357. ; |
Approved |
Most recent IF: 3.836; 2013 IF: 3.664 |
Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
UA @ lucian @ c:irua:109801 |
Serial |
1702 |
Permanent link to this record |
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Author |
Moldovan, D.; Masir, M.R.; Peeters, F.M. |
Title |
Electronic states in a graphene flake strained by a Gaussian bump |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
88 |
Issue |
3 |
Pages |
035446-35447 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The effect of strain in graphene is usually modeled by a pseudomagnetic vector potential which is, however, derived in the limit of small strain. In realistic cases deviations are expected in view of graphene's very high strain tolerance, which can be up to 25%. Here we investigate the pseudomagnetic field generated by a Gaussian bump and we show that it exhibits significant differences with numerical tight-binding results. Furthermore, we calculate the electronic states in the strained region for a hexagon shaped flake with armchair edges. We find that the sixfold symmetry of the wave functions inside the Gaussian bump is directly related to the different effects of strain along the fundamental directions of graphene: zigzag and armchair. Low energy electrons are strongly confined in the armchair directions and are localized on the carbon atoms of a single sublattice. |
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 |
000322587500003 |
Publication Date |
2013-07-30 |
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 |
Impact Factor |
3.836 |
Times cited |
50 |
Open Access |
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Notes |
; This work was supported by the European Science Foundation (ESF) under the EUROCORES Program Euro-GRAPHENE within the project CONGRAN, the Flemish Science Foundation (FWO-Vl), and the Methusalem Funding of the Flemish Government. ; |
Approved |
Most recent IF: 3.836; 2013 IF: 3.664 |
Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
UA @ lucian @ c:irua:109800 |
Serial |
1007 |
Permanent link to this record |
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Author |
Berdiyorov, G.R.; Doria, M.M.; de Romaguera, A.R.C.; Milošević, M.V.; Brandt, E.H.; Peeters, F.M. |
Title |
Current-induced cutting and recombination of magnetic superconducting vortex loops in mesoscopic superconductor-ferromagnet heterostructures |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
87 |
Issue |
18 |
Pages |
184508-5 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
Vortex loops are generated by the inhomogeneous stray field of a magnetic dipole on top of a current-carrying mesoscopic superconductor. Cutting and recombination processes unfold under the applied drive, resulting in periodic voltage oscillations across the sample. We show that a direct and detectable consequence of the cutting and recombination of these vortex loops in the present setup is the onset of vortices at surfaces where they were absent prior to the application of the external current. The nonlinear dynamics of vortex loops is studied within the time-dependent Ginzburg-Landau theory to describe the profound three-dimensional features of their time evolution. |
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Place of Publication |
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Editor |
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Language |
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Wos |
000319252000008 |
Publication Date |
2013-05-21 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
13 |
Open Access |
|
Notes |
; This work was supported by the Flemish Science Foundation (FWO-VI) and the bilateral programme between Flanders and Brazil. G.R.B. acknowledges support from FWO-VI. A.R. de C.R. acknowledges CNPq for financial support. ; |
Approved |
Most recent IF: 3.836; 2013 IF: 3.664 |
Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
UA @ lucian @ c:irua:109648 |
Serial |
593 |
Permanent link to this record |
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Author |
Berdiyorov, G.R.; Savel'ev, S.E.; Milošević, M.V.; Kusmartsev, F.V.; Peeters, F.M. |
Title |
Synchronized dynamics of Josephson vortices in artificial stacks of SNS Josephson junctions under both dc and ac bias currents |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
87 |
Issue |
18 |
Pages |
184510-184519 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
Nonlinear dynamics of Josephson vortices (fluxons) in artificial stacks of superconducting-normal-superconducting Josephson junctions under simultaneously applied time-periodic ac and constant biasing dc currents is studied using the time dependent Ginzburg-Landau formalism with a Lawrence-Doniach extension. At zero external magnetic field and dc biasing current the resistive state of the system is characterized by periodic nucleation and annihilation of fluxon-antifluxon pairs, relative positions of which are determined by the state of neighboring junctions. Due to the mutual repulsive interaction, fluxons in different junctions move out of phase. Their collective motion can be synchronized by adding a small ac component to the biasing dc current. Coherent motion of fluxons is observed for a broad frequency range of the applied drive. In the coherent state the maximal output voltage, which is proportional to the number of junctions in the stack, is observed near the characteristic frequency of the system determined by the crossing of the fluxons across the sample. However, in this frequency range the dynamically synchronized state has an alternative-a less ordered state with smaller amplitude of the output voltage. Collective behavior of the junctions is strongly affected by the sloped sidewalls of the stack. Synchronization is observed only for weakly trapezoidal cross sections, whereas irregular motion of fluxons is observed for larger slopes of the sample edge. |
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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 |
000319653400007 |
Publication Date |
2013-05-28 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
10 |
Open Access |
|
Notes |
; This work was supported by the Flemish Science Foundation (FWO-VI) and by EU Marie Curie (Project No. 253057). ; |
Approved |
Most recent IF: 3.836; 2013 IF: 3.664 |
Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
UA @ lucian @ c:irua:109643 |
Serial |
3406 |
Permanent link to this record |
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Author |
Govaerts, K.; Saniz, R.; Partoens, B.; Lamoen, D. |
Title |
van der Waals bonding and the quasiparticle band structure of SnO from first principles |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
87 |
Issue |
23 |
Pages |
235210-235217 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
Abstract |
In this work we have investigated the structural and electronic properties of SnO, which is built up from layers kept together by van der Waals (vdW) forces. The combination of a vdW functional within density functional theory (DFT) and quasiparticle band structure calculations within the GW approximation provides accurate values for the lattice parameters, atomic positions, and the electronic band structure including the fundamental (indirect) and the optical (direct) band gap without the need of experimental or empirical input. A systematic comparison is made between different levels of self-consistency within the GW approach {following the scheme of Shishkin et al. [Phys. Rev. B 75, 235102 (2007)]} and the results are compared with DFT and hybrid functional results. Furthermore, the effect of the vdW-corrected functional as a starting point for the GW calculation of the band gap has been investigated. Finally, we studied the effect of the vdW functional on the electron charge density. |
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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 |
000321061000003 |
Publication Date |
2013-07-01 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
50 |
Open Access |
|
Notes |
IWT; FWO; Hercules |
Approved |
Most recent IF: 3.836; 2013 IF: 3.664 |
Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
UA @ lucian @ c:irua:109596 |
Serial |
3835 |
Permanent link to this record |
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Author |
Bals, S.; Van Aert, S.; Van Tendeloo, G. |
Title |
High resolution electron tomography |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Current opinion in solid state and materials science |
Abbreviated Journal |
Curr Opin Solid St M |
Volume |
17 |
Issue |
3 |
Pages |
107-114 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Reaching atomic resolution in 3D has been the ultimate goal in the field of electron tomography for many years. Significant progress, both on the theoretical as well as the experimental side has recently resulted in several exciting examples demonstrating the ability to visualise atoms in 3D. In this paper, we will review the different steps that have pushed the resolution in 3D to the atomic level. A broad range of methodologies and practical examples together with their impact on materials science will be discussed. Finally, we will provide an outlook and will describe future challenges in the field of high resolution electron tomography. |
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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 |
000323869800003 |
Publication Date |
2013-03-30 |
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 |
1359-0286; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
6.938 |
Times cited |
24 |
Open Access |
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Notes |
Fwo; 312483 Esteem; Countatoms; |
Approved |
Most recent IF: 6.938; 2013 IF: 7.167 |
Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
UA @ lucian @ c:irua:109454 |
Serial |
1457 |
Permanent link to this record |
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Author |
Singh, S.K.; Neek-Amal, M.; Costamagna, S.; Peeters, F.M. |
Title |
Thermomechanical properties of a single hexagonal boron nitride sheet |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
87 |
Issue |
18 |
Pages |
184106-184107 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
Using atomistic simulations we investigate the thermodynamical properties of a single atomic layer of hexagonal boron nitride (h-BN). The thermal induced ripples, heat capacity, and thermal lattice expansion of large scale h-BN sheets are determined and compared to those found for graphene (GE) for temperatures up to 1000 K. By analyzing the mean-square height fluctuations < h(2)> and the height-height correlation function H(q) we found that the h-BN sheet is a less stiff material as compared to graphene. The bending rigidity of h-BN (i) is about 16% smaller than the one of GE at room temperature (300 K), and (ii) increases with temperature as in GE. The difference in stiffness between h-BN and GE results in unequal responses to external uniaxial and shear stress and different buckling transitions. In contrast to a GE sheet, the buckling transition of a h-BN sheet depends strongly on the direction of the applied compression. The molar heat capacity, thermal-expansion coefficient, and Gruneisen parameter are estimated to be 25.2 J mol(-1) K-1, 7.2 x 10(-6) K-1, and 0.89, respectively. |
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Corporate Author |
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Thesis |
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Place of Publication |
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Language |
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Wos |
000318653800001 |
Publication Date |
2013-05-08 |
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 |
Impact Factor |
3.836 |
Times cited |
80 |
Open Access |
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Notes |
; We thank K. H. Michel and D. A. Kirilenko for their useful comments on the manuscript. M. N.-A. was supported by EU-Marie Curie IIF Postdoctorate Fellowship No. 299855. S. Costamagna was supported by the Belgian Science Foundation (BELSPO). This work was supported by the ESF-EuroGRAPHENE project CONGRAN, the Flemish Science Foundation (FWO-Vl), and the Methusalem program of the Flemish Government. ; |
Approved |
Most recent IF: 3.836; 2013 IF: 3.664 |
Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
UA @ lucian @ c:irua:109010 |
Serial |
3638 |
Permanent link to this record |
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Author |
Szumniak, P.; Bednarek, S.; Pawlowski, J.; Partoens, B. |
Title |
All-electrical control of quantum gates for single heavy-hole spin qubits |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
87 |
Issue |
19 |
Pages |
195307-195312 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
In this paper several nanodevices which realize basic single heavy-hole qubit operations are proposed and supported by time-dependent self-consistent Poisson-Schrodinger calculations using a four band heavy-hole-light-hole model. In particular we propose a set of nanodevices which can act as Pauli X, Y, Z quantum gates and as a gate that acts similar to a Hadamard gate (i.e., it creates a balanced superposition of basis states but with an additional phase factor) on the heavy-hole spin qubit. We also present the design and simulation of a gated semiconductor nanodevice which can realize an arbitrary sequence of all these proposed single quantum logic gates. The proposed devices exploit the self-focusing effect of the hole wave function which allows for guiding the hole along a given path in the form of a stable solitonlike wave packet. Thanks to the presence of the Dresselhaus spin-orbit coupling, the motion of the hole along a certain direction is equivalent to the application of an effective magnetic field which induces in turn a coherent rotation of the heavy-hole spin. The hole motion and consequently the quantum logic operation is initialized only by weak static voltages applied to the electrodes which cover the nanodevice. The proposed gates allow for an all electric and ultrafast (tens of picoseconds) heavy-hole spin manipulation and give the possibility to implement a scalable architecture of heavy-hole spin qubits for quantum computation applications. |
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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 |
000319252200003 |
Publication Date |
2013-05-21 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
14 |
Open Access |
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Notes |
; This work was supported by the Polish National Science Center (Grant No. DEC-2011/03/N/ST3/02963), as well as by the “Krakow Interdisciplinary PhD-Project in Nanoscience and Advanced Nanostructures” operated within the Foundation for Polish Science MPD Programme, co-financed by the European Regional Development Fund. This research was supported in part by PL-Grid Infrastructure. ; |
Approved |
Most recent IF: 3.836; 2013 IF: 3.664 |
Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
UA @ lucian @ c:irua:109002 |
Serial |
88 |
Permanent link to this record |
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Author |
Van Duppen, B.; Peeters, F.M. |
Title |
Four-band tunneling in bilayer graphene |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
87 |
Issue |
20 |
Pages |
205427-10 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The conductance, the transmission, and the reflection probabilities through rectangular potential barriers and p-n junctions are obtained for bilayer graphene taking into account the four bands of the energy spectrum. We have evaluated the importance of the skew hopping parameters gamma(3) and gamma(4) to these properties and show that for energies E > gamma(1)/100 their effect is negligible. For high energies two modes of propagation exist and we investigate scattering between these modes. For perpendicular incidence both propagation modes are decoupled, and scattering between them is forbidden. This extends the concept of pseudospin as defined within the two-band approximation to a four-band model and corresponds to the (anti) symmetry of the wave functions under in-plane mirroring. New transmission resonances are found that appear as sharp peaks in the conductance which are absent in the two-band approximation. The application of an interlayer bias to the system (1) breaks the pseudospin structure, (2) opens a band gap that results in a distinct feature of suppressed transmission in the conductance, and (3) breaks the angular symmetry with respect to normal incidence in the transmission and reflection. |
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Corporate Author |
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Place of Publication |
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Editor |
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Language |
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Wos |
000319282000002 |
Publication Date |
2013-05-21 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
37 |
Open Access |
|
Notes |
; This work was supported by the European Science Foundation (ESF) under the EUROCORES Program Euro-GRAPHENE within the project CONGRAN, the Flemish Science Foundation (FWO-Vl) by an aspirant research grant to B. Van Duppen and the Methusalem Programme of the Flemish Government. ; |
Approved |
Most recent IF: 3.836; 2013 IF: 3.664 |
Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
UA @ lucian @ c:irua:109001 |
Serial |
1269 |
Permanent link to this record |