|
Records |
Links |
|
Author |
Nasr Esfahani, D.; Covaci, L.; Peeters, F.M. |
|
|
Title |
Surface correlation effects in two-band strongly correlated slabs |
Type |
A1 Journal article |
|
Year |
2014 |
Publication |
Journal of physics : condensed matter |
Abbreviated Journal |
J Phys-Condens Mat |
|
|
Volume |
26 |
Issue |
7 |
Pages |
075601-75609 |
|
|
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
|
Abstract |
Using an extension of the Gutzwiller approximation for an inhomogeneous system, we study the two-band Hubbard model with unequal band widths for a slab geometry. The aim is to investigate the mutual effect of individual bands on the spatial distribution of quasi-particle weight and charge density, especially near the surface of the slab. The main effect of the difference in band width is the presence of two different length scales corresponding to the quasi-particle profile of each band. This is enhanced in the vicinity of the critical interaction of the narrow band where an orbitally selective Mott transition occurs and a surface dead layer forms for the narrow band. For the doped case, two different regimes of charge transfer between the surface and the bulk of the slab are revealed. The charge transfer from surface/ center to center/ surface depends on both the doping level and the average relative charge accumulated in each band. Such effects could also be of importance when describing the accumulation of charges at the interface between structures made of multi-band strongly correlated materials. |
|
|
Address |
|
|
|
Corporate Author |
|
Thesis |
|
|
|
Publisher |
|
Place of Publication |
London |
Editor |
|
|
|
Language |
|
Wos |
000330719500009 |
Publication Date |
2014-01-29 |
|
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
0953-8984;1361-648X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
|
Impact Factor |
2.649 |
Times cited |
1 |
Open Access |
|
|
|
Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Methusalem program of the Flemish government. One of us (LC) is a postdoctoral fellow of the FWO-Vl. ; |
Approved |
Most recent IF: 2.649; 2014 IF: 2.346 |
|
|
Call Number |
UA @ lucian @ c:irua:115723 |
Serial |
3395 |
|
Permanent link to this record |
|
|
|
|
Author |
de Sousa, J.S.; Covaci, L.; Peeters, F.M.; Farias, G.A. |
|
|
Title |
Time-dependent investigation of charge injection in a quantum dot containing one electron |
Type |
A1 Journal article |
|
Year |
2012 |
Publication |
Journal of applied physics |
Abbreviated Journal |
J Appl Phys |
|
|
Volume |
112 |
Issue |
9 |
Pages |
093705-93709 |
|
|
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
|
Abstract |
The interaction of an injected electron towards a quantum dot (QD) containing a single confined electron is investigated using a flexible time-dependent quantum mechanics formalism, which allows both electrons to move and undergo quantum transitions. Different scenarios combining quantum dot dimensions, dielectric constant, injected wave packet energy, and width were explored, and our main results are: (i) due to the large characteristic transitions times between the confined state in the quantum dot and the delocalized state in the continuum, it is relatively difficult to ionize the occupied QD by Coulomb interaction solely and (ii) the charging state of the quantum dot can be sensed by direct injection of charges. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4759292] |
|
|
Address |
|
|
|
Corporate Author |
|
Thesis |
|
|
|
Publisher |
American Institute of Physics |
Place of Publication |
New York, N.Y. |
Editor |
|
|
|
Language |
|
Wos |
000311968400052 |
Publication Date |
2012-11-06 |
|
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
0021-8979; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
|
Impact Factor |
2.068 |
Times cited |
1 |
Open Access |
|
|
|
Notes |
; This work was financially supported by the Brazilian National Research Council (CNPq), under Contract No. NanoBioEstruturas 555183/2005-0, Fundao Cearense de Apoio ao Desenvolvimento Cientfico e Tecnolgico (Funcap), CAPES, Pronex/CNPq/ Funcap, the Bilateral program between Flanders and Brazil, and the Flemish Science Foundation (FWO). ; |
Approved |
Most recent IF: 2.068; 2012 IF: 2.210 |
|
|
Call Number |
UA @ lucian @ c:irua:106014 |
Serial |
3664 |
|
Permanent link to this record |
|
|
|
|
Author |
Milovanović, S.P.; Covaci, L.; Peeters, F.M. |
|
|
Title |
Strain fields in graphene induced by nanopillar mesh |
Type |
A1 Journal article |
|
Year |
2019 |
Publication |
Journal of applied physics |
Abbreviated Journal |
J Appl Phys |
|
|
Volume |
125 |
Issue |
8 |
Pages |
082534 |
|
|
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
|
Abstract |
The mechanical and electronic properties of a graphene membrane placed on top of a triangular superlattice of nanopillars are investigated. We use molecular dynamics simulations to access the deformation fields and the tight-binding approaches to calculate the electronic properties. Ripples form in the graphene layer that span across the unit cell, connecting neighboring pillars, in agreement with recent experiments. We find that the resulting pseudo-magnetic field (PMF) varies strongly across the unit cell. We investigate the dependence of PMF on unit cell boundary conditions, height of the pillars, and the strength of the van der Waals interaction between graphene and the substrate. We find direct correspondence with typical experiments on pillars, showing intrinsic “slack” in the graphene membrane. PMF values are confirmed by the local density of states calculations performed at different positions of the unit cell showing pseudo-Landau levels with varying spacings. Our findings regarding the relaxed membrane configuration and the induced strains are transferable to other flexible 2D membranes. |
|
|
Address |
|
|
|
Corporate Author |
|
Thesis |
|
|
|
Publisher |
|
Place of Publication |
|
Editor |
|
|
|
Language |
|
Wos |
000460033800038 |
Publication Date |
2019-01-16 |
|
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
0021-8979; 1089-7550 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
|
Impact Factor |
2.068 |
Times cited |
9 |
Open Access |
|
|
|
Notes |
; S.P.M. is supported by the Flemish Science Foundation (FWO). ; |
Approved |
Most recent IF: 2.068 |
|
|
Call Number |
UA @ admin @ c:irua:158605 |
Serial |
5231 |
|
Permanent link to this record |
|
|
|
|
Author |
Villarreal, R.; Lin, P.-C.; Faraji, F.; Hassani, N.; Bana, H.; Zarkua, Z.; Nair, M.N.; Tsai, H.-C.; Auge, M.; Junge, F.; Hofsaess, H.C.; De Gendt, S.; De Feyter, S.; Brems, S.; Ahlgren, E.H.; Neyts, E.C.; Covaci, L.; Peeters, F.M.; Neek-Amal, M.; Pereira, L.M.C. |
|
|
Title |
Breakdown of universal scaling for nanometer-sized bubbles in graphene |
Type |
A1 Journal article |
|
Year |
2021 |
Publication |
Nano Letters |
Abbreviated Journal |
Nano Lett |
|
|
Volume |
21 |
Issue |
19 |
Pages |
8103-8110 |
|
|
Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
|
|
Abstract |
We report the formation of nanobubbles on graphene with a radius of the order of 1 nm, using ultralow energy implantation of noble gas ions (He, Ne, Ar) into graphene grown on a Pt(111) surface. We show that the universal scaling of the aspect ratio, which has previously been established for larger bubbles, breaks down when the bubble radius approaches 1 nm, resulting in much larger aspect ratios. Moreover, we observe that the bubble stability and aspect ratio depend on the substrate onto which the graphene is grown (bubbles are stable for Pt but not for Cu) and trapped element. We interpret these dependencies in terms of the atomic compressibility of the noble gas as well as of the adhesion energies between graphene, the substrate, and trapped atoms. |
|
|
Address |
|
|
|
Corporate Author |
|
Thesis |
|
|
|
Publisher |
|
Place of Publication |
|
Editor |
|
|
|
Language |
|
Wos |
000709549100026 |
Publication Date |
2021-09-14 |
|
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
1530-6984 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
|
Impact Factor |
12.712 |
Times cited |
24 |
Open Access |
OpenAccess |
|
|
Notes |
|
Approved |
Most recent IF: 12.712 |
|
|
Call Number |
UA @ admin @ c:irua:184137 |
Serial |
6857 |
|
Permanent link to this record |
|
|
|
|
Author |
Andelkovic, M.; Milovanović, S.P.; Covaci, L.; Peeters, F.M. |
|
|
Title |
Double moiré with a twist : supermoiré in encapsulated graphene |
Type |
A1 Journal article |
|
Year |
2020 |
Publication |
Nano Letters |
Abbreviated Journal |
Nano Lett |
|
|
Volume |
20 |
Issue |
2 |
Pages |
979 |
|
|
Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
|
|
Abstract |
A periodic spatial modulation, as created by a moire pattern, has been extensively studied with the view to engineer and tune the properties of graphene. Graphene encapsulated by hexagonal boron nitride (hBN) when slightly misaligned with the top and bottom hBN layers experiences two interfering moire patterns, resulting in a so-called supermoire (SM). This leads to a lattice and electronic spectrum reconstruction. A geometrical construction of the nonrelaxed SM patterns allows us to indicate qualitatively the induced changes in the electronic properties and to locate the SM features in the density of states and in the conductivity. To emphasize the effect of lattice relaxation, we report band gaps at all Dirac-like points in the hole doped part of the reconstructed spectrum, which are expected to be enhanced when including interaction effects. Our result is able to distinguish effects due to lattice relaxation and due to the interfering SM and provides a clear picture on the origin of recently experimentally observed effects in such trilayer heterostuctures. |
|
|
Address |
|
|
|
Corporate Author |
|
Thesis |
|
|
|
Publisher |
|
Place of Publication |
|
Editor |
|
|
|
Language |
|
Wos |
000514255400021 |
Publication Date |
2020-01-21 |
|
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
1530-6984 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
|
Impact Factor |
10.8 |
Times cited |
48 |
Open Access |
OpenAccess |
|
|
Notes |
; This work was funded by FLAGERA project TRANS2DTMD and the Flemish Science Foundation (FWO-Vl) through a postdoc fellowship for S.P.M. The authors acknowledge useful discussions with W. Zihao and K. Novoselov. ; |
Approved |
Most recent IF: 10.8; 2020 IF: 12.712 |
|
|
Call Number |
UA @ admin @ c:irua:168685 |
Serial |
6490 |
|
Permanent link to this record |
|
|
|
|
Author |
Zhang, L.-F.; Covaci, L.; Peeters, F.M. |
|
|
Title |
Position-dependent effect of non-magnetic impurities on superconducting properties of nanowires |
Type |
A1 Journal article |
|
Year |
2015 |
Publication |
Europhysics letters |
Abbreviated Journal |
Epl-Europhys Lett |
|
|
Volume |
109 |
Issue |
109 |
Pages |
17010 |
|
|
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
|
Abstract |
Anderson's theorem states that non-magnetic impurities do not change the bulk properties of conventional superconductors. However, as the dimensionality is reduced, the effect of impurities becomes more significant. Here we investigate superconducting nanowires with diameter comparable to the Fermi wavelength $\lambda_F$ (which is less than the superconducting coherence length) by using a microscopic description based on the Bogoliubov-de Gennes method. We find that: 1) impurities strongly affect the superconducting properties, 2) the effect is impurity position dependent, and 3) it exhibits opposite behavior for resonant and off-resonant wire widths. We show that this is due to the interplay between the shape resonances of the order parameter and the subband energy spectrum induced by the lateral quantum confinement. These effects can be used to manipulate the Josephson current, filter electrons by subband and investigate the symmetries of the superconducting subband gaps. |
|
|
Address |
|
|
|
Corporate Author |
|
Thesis |
|
|
|
Publisher |
|
Place of Publication |
Paris |
Editor |
|
|
|
Language |
|
Wos |
000348592100029 |
Publication Date |
2015-01-21 |
|
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
0295-5075 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
|
Impact Factor |
1.957 |
Times cited |
7 |
Open Access |
|
|
|
Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vlaanderen) and the Methusalem funding of the Flemish Government. ; |
Approved |
Most recent IF: 1.957; 2015 IF: 2.095 |
|
|
Call Number |
UA @ lucian @ c:irua:128424 |
Serial |
4227 |
|
Permanent link to this record |
|
|
|
|
Author |
Kim, W.; Covaci, L.; Dogan, F.; Marsiglio, F. |
|
|
Title |
Quantum mechanics of spin transfer in coupled electron-spin chains |
Type |
A1 Journal article |
|
Year |
2007 |
Publication |
Epl |
Abbreviated Journal |
Epl-Europhys Lett |
|
|
Volume |
79 |
Issue |
6 |
Pages |
67004 |
|
|
Keywords |
A1 Journal article |
|
|
Abstract |
The manner in which spin-polarized electrons interact with a magnetized thin film is currently described by a semi-classical approach. This in turn provides our present understanding of the spin transfer, or spin torque phenomenon. However, spin is an intrinsically quantum-mechanical quantity. Here, we make the first strides towards a fully quantum-mechanical description of spin transfer through spin currents interacting with a Heisenberg-coupled spin chain. Because of quantum entanglement, this requires a formalism based on the density matrix approach. Our description illustrates how individual spins in the chain time-evolve as a result of spin transfer. |
|
|
Address |
|
|
|
Corporate Author |
|
Thesis |
|
|
|
Publisher |
|
Place of Publication |
|
Editor |
|
|
|
Language |
|
Wos |
000250409500023 |
Publication Date |
2007-08-24 |
|
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
0295-5075 |
ISBN |
|
Additional Links |
|
|
|
Impact Factor |
1.957 |
Times cited |
3 |
Open Access |
|
|
|
Notes |
|
Approved |
Most recent IF: 1.957; 2007 IF: 2.206 |
|
|
Call Number |
UA @ lucian @ |
Serial |
4430 |
|
Permanent link to this record |
|
|
|
|
Author |
Covaci, L.; Berciu, M. |
|
|
Title |
Holstein polaron: The effect of coupling to multiple-phonon modes |
Type |
A1 Journal article |
|
Year |
2007 |
Publication |
Epl |
Abbreviated Journal |
Epl-Europhys Lett |
|
|
Volume |
80 |
Issue |
6 |
Pages |
67001 |
|
|
Keywords |
A1 Journal article |
|
|
Abstract |
We investigate the effects of coupling to multiple-phonon modes on the properties of a Holstein polaron. To this end, we generalize the Momentum Average approximations MA((0)) and MA((1)) to deal with multiple-phonon modes. As for a single-phonon mode, these approximations are found to be numerically very efficient. They become exact for very weak or very strong couplings, and are highly accurate in the intermediate regimes, e.g. the spectral weights obey exactly the first six, respectively eight, sum rules. Our results show that the effect on ground-state properties is cumulative in nature. As a result, if the effective coupling to one mode is much larger than to all the others, this mode effectively determines the ground-state properties. However, even very weak coupling to a second phonon mode has important non-perturbational effects on the higher-energy spectrum, in particular on the dispersion and the phonon statistics of the polaron band. This has important consequences on the analysis and interpretation of data for real materials. |
|
|
Address |
|
|
|
Corporate Author |
|
Thesis |
|
|
|
Publisher |
|
Place of Publication |
|
Editor |
|
|
|
Language |
|
Wos |
000251648300016 |
Publication Date |
2007-11-30 |
|
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
0295-5075 |
ISBN |
|
Additional Links |
|
|
|
Impact Factor |
1.957 |
Times cited |
9 |
Open Access |
|
|
|
Notes |
|
Approved |
Most recent IF: 1.957; 2007 IF: 2.206 |
|
|
Call Number |
UA @ lucian @ |
Serial |
4431 |
|
Permanent link to this record |
|
|
|
|
Author |
Berdiyorov, G.R.; de Romaguera, A.R.C.; Milošević, M.V.; Doria, M.M.; Covaci, L.; Peeters, F.M. |
|
|
Title |
Dynamic and static phases of vortices under an applied drive in a superconducting stripe with an array of weak links |
Type |
A1 Journal article |
|
Year |
2012 |
Publication |
European physical journal : B : condensed matter and complex systems |
Abbreviated Journal |
Eur Phys J B |
|
|
Volume |
85 |
Issue |
4 |
Pages |
130-130,8 |
|
|
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
|
Abstract |
Static and dynamic properties of superconducting vortices in a superconducting stripe with a periodic array of weakly-superconducting (or normal metal) regions are studied in the presence of external magnetic and electric fields. The time-dependent Ginzburg-Landau theory is used to describe the electronic transport, where the anisotropy is included through the spatially-dependent critical temperature T-c. Superconducting vortices penetrating into the weak-superconducting region with smaller T-c are more mobile than the ones in the strong superconducting regions. We observe periodic entrance and exit of vortices which reside in the weak link for some short interval. The mobility of the weakly-pinned vortices can be reduced by increasing the uniform applied magnetic field leading to distinct features in the voltage vs. magnetic field response of the system. |
|
|
Address |
|
|
|
Corporate Author |
|
Thesis |
|
|
|
Publisher |
|
Place of Publication |
Berlin |
Editor |
|
|
|
Language |
|
Wos |
000303545400013 |
Publication Date |
2012-04-20 |
|
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
1434-6028;1434-6036; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
|
Impact Factor |
1.461 |
Times cited |
32 |
Open Access |
|
|
|
Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl), the Belgian Science Policy (IAP), the bilateral programme between Flanders and Brazil. G.R.B. and L.C. acknowledge individual support from FWO-Vl. A.R.de C.R. acknowledges CNPq and FACEPE for financial support. ; |
Approved |
Most recent IF: 1.461; 2012 IF: 1.282 |
|
|
Call Number |
UA @ lucian @ c:irua:98267 |
Serial |
761 |
|
Permanent link to this record |