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| Author | Rezaei, M.; Sisakht, E.T.; Fazileh, F.; Aslani, Z.; Peeters, F.M. | ||||
| Title | Tight-binding model investigation of the biaxial strain induced topological phase transition in GeCH3 | Type | A1 Journal article | ||
| Year | 2017 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
Volume  |
96 | Issue | 8 | Pages | 085441 |
| Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
| Abstract | We propose a tight-binding (TB) model, that includes spin-orbit coupling (SOC), to describe the electronic properties of methyl-substituted germanane (GeCH3). This model gives an electronic spectrum in agreement with first principle results close to the Fermi level. Using the Z(2) formalism, we show that a topological phase transition from a normal insulator (NI) to a quantum spin Hall (QSH) phase occurs at 11.6% biaxial tensile strain. The sensitivity of the electronic properties of this system on strain, in particular its transition to the topological insulating phase, makes it very attractive for applications in strain sensors and other microelectronic applications. | ||||
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| Corporate Author | Thesis | ||||
| Publisher | American Physical Society | Place of Publication | New York, N.Y | Editor | |
| Language | Wos | 000408570800004 | Publication Date | 2017-08-29 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9969; 2469-9950 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 10 | Open Access | |
| Notes | ; ; | Approved | Most recent IF: 3.836 | ||
| Call Number | UA @ lucian @ c:irua:145697 | Serial | 4755 | ||
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| Author | Tsirlin, A.A.; Rousochatzakis, I.; Filimonov, D.; Batuk, D.; Frontzek, M.; Abakumov, A.M. | ||||
| Title | Spin-reorientation transitions in the Cairo pentagonal magnet Bi4Fe5O13F | Type | A1 Journal article | ||
| Year | 2017 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
| Volume |
96 | Issue | 9 | Pages | 094420 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | We show that interlayer spins play a dual role in the Cairo pentagonal magnet Bi4Fe5O13F, on one hand mediating the three-dimensional magnetic order, and on the other driving spin-reorientation transitions both within and between the planes. The corresponding sequence of magnetic orders unraveled by neutron diffraction and Mossbauer spectroscopy features two orthogonal magnetic structures described by opposite local vector chiralities, and an intermediate, partly disordered phase with nearly collinear spins. A similar collinear phase has been predicted theoretically to be stabilized by quantum fluctuations, but Bi4Fe5O13F is very far from the relevant parameter regime. While the observed in-plane reorientation cannot be explained by any standard frustration mechanism, our ab initio band-structure calculations reveal strong single-ion anisotropy of the interlayer Fe3+ spins that turns out to be instrumental in controlling the local vector chirality and the associated interlayer order. | ||||
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| Language | Wos | 000411161700002 | Publication Date | 2017-09-19 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9950 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 7 | Open Access | OpenAccess |
| Notes | We are grateful to J.-M. Perez-Mato and Dmitry Khalyavin for valuable discussions on the magnetic structures and symmetries. D.F. and A.A. are grateful to the Russian Science Foundation (Grant No. 14-13-00680) for support. A.T. was supported by the Federal Ministry for Education and Research through the Sofja Kovalevskaya Award of the Alexander von Humboldt Foundation. This work is based on experiments performed at the Swiss spallation neutron source SINQ, Paul Scherrer Institut, Villigen, Switzerland. | Approved | Most recent IF: 3.836 | ||
| Call Number | EMAT @ emat @c:irua:146748 | Serial | 4774 | ||
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| Author | Li, L.L.; Moldovan, D.; Xu, W.; Peeters, F.M. | ||||
| Title | Electronic properties of bilayer phosphorene quantum dots in the presence of perpendicular electric and magnetic fields | Type | A1 Journal article | ||
| Year | 2017 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
| Volume |
96 | Issue | 15 | Pages | 155425 |
| Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
| Abstract | Using the tight-binding approach, we investigate the electronic properties of bilayer phosphorene (BLP) quantum dots (QDs) in the presence of perpendicular electric and magnetic fields. Since BLP consists of two coupled phosphorene layers, it is of interest to examine the layer-dependent electronic properties of BLP QDs, such as the electronic distributions over the two layers and the so-produced layer-polarization features, and to see how these properties are affected by the magnetic field and the bias potential. We find that in the absence of a bias potential only edge states are layer polarized while the bulk states are not, and the layer-polarization degree (LPD) of the unbiased edge states increases with increasing magnetic field. However, in the presence of a bias potential both the edge and bulk states are layer polarized, and the LPD of the bulk (edge) states depends strongly (weakly) on the interplay of the bias potential and the interlayer coupling. At high magnetic fields, applying a bias potential renders the bulk electrons in a BLP QD to be mainly distributed over the top or bottom layer, resulting in layer-polarized bulk Landau levels (LLs). In the presence of a large bias potential that can drive a semiconductor-to-semimetal transition in BLP, these bulk LLs exhibit different magnetic-field dependences, i.e., the zeroth LLs exhibit a linearlike dependence on the magnetic field while the other LLs exhibit a square-root-like dependence. | ||||
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| Corporate Author | Thesis | ||||
| Publisher | American Physical Society | Place of Publication | New York, N.Y | Editor | |
| Language | Wos | 000412699800005 | Publication Date | 2017-10-10 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9969; 2469-9950 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 28 | Open Access | |
| Notes | ; This work was financially supported by the Flemish Science Foundation (FWO-Vl), the National Natural Science Foundation of China (Grant No. 11574319), and the Chinese Academy of Sciences. ; | Approved | Most recent IF: 3.836 | ||
| Call Number | UA @ lucian @ c:irua:146686 | Serial | 4782 | ||
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| Author | Mirzakhani, M.; Zarenia, M.; Vasilopoulos, P.; Ketabi, S.A.; Peeters, F.M. | ||||
| Title | Landau levels in biased graphene structures with monolayer-bilayer interfaces | Type | A1 Journal article | ||
| Year | 2017 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
| Volume |
96 | Issue | 12 | Pages | 125430 |
| Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
| Abstract | The electron energy spectrum in monolayer-bilayer-monolayer and in bilayer-monolayer-bilayer graphene structures is investigated and the effects of a perpendicular magnetic field and electric bias are studied. Different types of monolayer-bilayer interfaces are considered as zigzag (ZZ) or armchair (AC) junctions which modify considerably the bulk Landau levels (LLs) when the spectra are plotted as a function of the center coordinate of the cyclotron orbit. Far away from the two interfaces, one obtains the well-known LLs for extended monolayer or bilayer graphene. The LL structure changes significantly at the two interfaces or junctions where the valley degeneracy is lifted for both types of junctions, especially when the distance between them is approximately equal to the magnetic length. Varying the nonuniform bias and the width of this junction-to-junction region in either structure strongly influence the resulting spectra. Significant differences exist between ZZ and AC junctions in both structures. The densities of states (DOSs) for unbiased structures are symmetric in energy whereas those for biased structures are asymmetric. An external bias creates interface LLs in the gaps between the LLs of the unbiased system in which the DOS can be quite small. Such a pattern of LLs can be probed by scanning tunneling microscopy. | ||||
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| Corporate Author | Thesis | ||||
| Publisher | American Physical Society | Place of Publication | New York, N.Y | Editor | |
| Language | Wos | 000411321800003 | Publication Date | 2017-09-21 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9969; 2469-9950 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 6 | Open Access | |
| Notes | ; This work was supported by the BOF-UA (Bijzonder Onderzoeks Fonds), the Canadian NSERC through Grant No. OGP0121756 (P.V.), and the Methusalem Program of the Flemish Government. ; | Approved | Most recent IF: 3.836 | ||
| Call Number | UA @ lucian @ c:irua:146746 | Serial | 4787 | ||
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| Author | Nascimento, J.S.; da Costa, D.R.; Zarenia, M.; Chaves, A.; Pereira, J.M., Jr. | ||||
| Title | Magnetic properties of bilayer graphene quantum dots in the presence of uniaxial strain | Type | A1 Journal article | ||
| Year | 2017 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
| Volume |
96 | Issue | 11 | Pages | 115428 |
| Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
| Abstract | Using the tight-binding approach coupled with mean-field Hubbard model, we theoretically study the effect of mechanical deformations on the magnetic properties of bilayer graphene (BLG) quantum dots (QDs). Results are obtained for AA-and AB(Bernal)-stacked BLG QDs, considering different geometries (hexagonal, triangular and square shapes) and edge types (armchair and zigzag edges). In the absence of strain, our results show that (i) the magnetization is affected by taking different dot sizes only for hexagonal BLG QDs with zigzag edges, exhibiting different critical Hubbard interactions, and (ii) the magnetization does not depend on the interlayer hopping energies, except for the geometries with zigzag edges and AA stacking. In the presence of in-plane and uniaxial strain, for all geometries we obtain two different magnetization regimes depending on the applied strain amplitude. The appearance of such different regimes is due to the breaking of layer and sublattice symmetries in BLG QDs. | ||||
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| Corporate Author | Thesis | ||||
| Publisher | American Physical Society | Place of Publication | New York, N.Y | Editor | |
| Language | Wos | 000411077400008 | Publication Date | 2017-09-18 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9969; 2469-9950 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 4 | Open Access | |
| Notes | ; This work was financially supported by CNPq, FUNCAP, CAPES Foundation, the Flemish Science Foundation (FWO-Vl), and the Brazilian Program Science Without Borders (CsF). ; | Approved | Most recent IF: 3.836 | ||
| Call Number | UA @ lucian @ c:irua:146751 | Serial | 4788 | ||
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| Author | Zhang, L.-F.; Flammia, L.; Covaci, L.; Perali, A.; Milošević, M.V. | ||||
| Title | Multifaceted impact of a surface step on superconductivity in atomically thin films | Type | A1 Journal article | ||
| Year | 2017 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
| Volume |
96 | Issue | 10 | Pages | 104509 |
| Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
| Abstract | Recent experiments show that an atomic step on the surface of atomically thin metallic films can strongly affect electronic transport. Here we reveal multiple and versatile effects that such a surface step can have on superconductivity in ultrathin films. By solving the Bogoliubov-de Gennes equations self-consistently in this regime, where quantum confinement dominates the emergent physics, we show that the electronic structure is profoundly modified on the two sides of the step, as is the spatial distribution of the superconducting order parameter and its dependence on temperature and electronic gating. Furthermore, the surface step changes nontrivially the transport properties both in the proximity-induced superconducting pair correlations and the Josephson effect, depending on the step height. These results offer a new route to tailor superconducting circuits and design atomically thin heterojunctions made of one same material. | ||||
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| Corporate Author | Thesis | ||||
| Publisher | American Physical Society | Place of Publication | New York, N.Y | Editor | |
| Language | Wos | 000411076000012 | Publication Date | 2017-09-18 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9969; 2469-9950 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 7 | Open Access | |
| Notes | ; This work was supported by the Research Foundation Flanders (FWO-Vlaanderen), the Special Research Funds of the University of Antwerp (TOPBOF project) and the Italian MIUR through the PRIN 2015 program (Contract No. 2015C5SEJJ001). ; | Approved | Most recent IF: 3.836 | ||
| Call Number | UA @ lucian @ c:irua:146750 | Serial | 4790 | ||
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| Author | Arsoski, V.V.; Grujić, M.M.; Čukarić, N.A.; Tadic, M.Z.; Peeters, F.M. | ||||
| Title | Normal and skewed phosphorene nanoribbons in combined magnetic and electric fields | Type | A1 Journal article | ||
| Year | 2017 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
| Volume |
96 | Issue | 12 | Pages | 125434 |
| Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
| Abstract | The energy spectrum and eigenstates of single-layer black phosphorus nanoribbons in the presence of a perpendicular magnetic field and an in-plane transverse electric field are investigated by means of a tight-binding method, and the effect of different types of edges is examined analytically. A description based on a continuum model is proposed using an expansion of the tight-binding model in the long-wavelength limit. Thewave functions corresponding to the flatband part of the spectrum are obtained analytically and are shown to agree well with the numerical results from the tight-binding method for both narrow (10 nm) and wide (100 nm) nanoribbons. Analytical expressions for the critical magnetic field at which Landau levels are formed and the ranges of wave numbers in the dispersionless flatband segments in the energy spectra are derived. We examine the evolution of the Landau levels when an in-plane lateral electric field is applied, and we determine analytically how the edge states shift withmagnetic field. For wider nanoribbons, the conductance is shown to have a characteristic staircase shape in combined magnetic and electric fields. Some of the stairs in zigzag and skewed armchair nanoribbons originate from edge states that are found in the band gap. | ||||
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| Corporate Author | Thesis | ||||
| Publisher | American Physical Society | Place of Publication | New York, N.Y | Editor | |
| Language | Wos | 000411572400008 | Publication Date | 2017-09-25 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9969; 2469-9950 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 8 | Open Access | |
| Notes | ; This work was supported by Erasmus+, the Serbian Ministry of Education, Science and Technological Development, and the Flemish Science Foundation (FWO-Vl). ; | Approved | Most recent IF: 3.836 | ||
| Call Number | UA @ lucian @ c:irua:146738 | Serial | 4791 | ||
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| Author | Augustyns, V.; van Stiphout, K.; Joly, V.; Lima, T.A.L.; Lippertz, G.; Trekels, M.; Menendez, E.; Kremer, F.; Wahl, U.; Costa, A.R.G.; Correia, J.G.; Banerjee, D.; Gunnlaugsson, H.P.; von Bardeleben, J.; Vickridge, I.; Van Bael, M.J.; Hadermann, J.; Araujo, J.P.; Temst, K.; Vantomme, A.; Pereira, L.M.C. | ||||
| Title | Evidence of tetragonal distortion as the origin of the ferromagnetic ground state in gamma-Fe nanoparticles | Type | A1 Journal article | ||
| Year | 2017 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
| Volume |
96 | Issue | 17 | Pages | 174410 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | <script type='text/javascript'>document.write(unpmarked('gamma-Fe and related alloys are model systems of the coupling between structure and magnetism in solids. Since different electronic states (with different volumes and magnetic ordering states) are closely spaced in energy, small perturbations can alter which one is the actual ground state. Here, we demonstrate that the ferromagnetic state of gamma-Fe nanoparticles is associated with a tetragonal distortion of the fcc structure. Combining a wide range of complementary experimental techniques, including low-temperature Mossbauer spectroscopy, advanced transmission electron microscopy, and synchrotron radiation techniques, we unambiguously identify the tetragonally distorted ferromagnetic ground state, with lattice parameters a = 3.76(2) angstrom and c = 3.50(2) angstrom, and a magnetic moment of 2.45(5) mu(B) per Fe atom. Our findings indicate that the ferromagnetic order in nanostructured gamma-Fe is generally associated with a tetragonal distortion. This observation motivates a theoretical reassessment of the electronic structure of gamma-Fe taking tetragonal distortion into account.')); | ||||
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| Publisher | American Physical Society | Place of Publication | New York, N.Y | Editor | |
| Language | Wos | 000414525200005 | Publication Date | 2017-11-07 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9969; 2469-9950 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 1 | Open Access | OpenAccess |
| Notes | ; The authors thank the Fund for Scientific Research-Flanders, the Concerted Research Action of the KU Leuven (GOA/14/007), the KU Leuven BOF (STRT/14/002), the Hercules Foundation, the Portuguese Foundation for Science and Technology (CERN/FIS-NUC/0004/2015), and the European Union Seventh Framework through ENSAR2 (European Nuclear Science and Applications Research, Project No. 654002), and SPIRIT (Support of Public and Industrial Research Using Ion Beam Technology, Contract No. 227012). We acknowledge the European Synchrotron Radiation Facility (ESRF) for providing beam time (experiments 26-01-1018, 26-01-1057, 20-02-728, HC-1850, HC-2208), as well as C. Baehtz, N. Boudet, and N. Blancand for support during the experiments. We acknowledge the ISOLDE-CERN facility for providing beam time (experiment IS580) and technical assistance. The authors (L.M.C.P., F.K.) acknowledge the facilities and the scientific and technical assistance of the Australian Microscopy & Microanalysis Research Facility at the Centre for Advanced Microscopy, Australian National University. We also acknowledge the contribution of Prof. Mark Ridgway (Australian National University), who passed away before the work was completed. ; | Approved | Most recent IF: 3.836 | ||
| Call Number | UA @ lucian @ c:irua:147387 | Serial | 4873 | ||
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| Author | Carmesin, C.; Schowalter, M.; Lorke, M.; Mourad, D.; Grieb, T.; Müller-Caspary, K.; Yacob, M.; Reithmaier, J.P.; Benyoucef, M.; Rosenauer, A.; Jahnke, F. | ||||
| Title | Interplay of morphology, composition, and optical properties of InP-based quantum dots emitting at the 1.55 \mum telecom wavelength | Type | A1 Journal article | ||
| Year | 2017 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
| Volume |
96 | Issue | 23 | Pages | 235309 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | <script type='text/javascript'>document.write(unpmarked('Results for the development and detailed analysis of self-organized InAs/InAlGaAs/InP quantum dots suitable for single-photon emission at the 1.55 mu m telecom wavelength are reported. The structural and compositional properties of the system are obtained from high-resolution scanning transmission electron microscopy of individual quantum dots. The system is composed of almost pure InAs quantum dots embedded in quaternary InAlGaAs barrier material, which is lattice matched to the InP substrate. When using the measured results for a representative quantum-dot geometry as well as experimentally reconstructed alloy concentrations, a combination of strain-field and electronic-state calculations is able to reproduce the quantum-dot emission wavelength in agreement with the experimentally determined photoluminescence spectrum. The inhomogeneous broadening of the latter can be related to calculated variations of the emission wavelength for the experimentally deduced In-concentration fluctuations and size variations.')); | ||||
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| Publisher | American Physical Society | Place of Publication | New York, N.Y | Editor | |
| Language | Wos | 000418654200009 | Publication Date | 2017-12-26 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9969; 2469-9950 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 3 | Open Access | OpenAccess |
| Notes | ; The authors gratefully acknowledge financial support from the Deutsche Forschungsgemeinschaft Project No. JA 14-1, the BMBF Projects Q.com-H No. 16KIS0111 and No. 16KIS0112, as well as computational resources from HLRN (Hannover, Berlin). ; | Approved | Most recent IF: 3.836 | ||
| Call Number | UA @ lucian @ c:irua:148505 | Serial | 4882 | ||
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| Author | Stosic, D.; Ludermir, T.B.; Milošević, M.V. | ||||
| Title | Pinning of magnetic skyrmions in a monolayer Co film on Pt(111) : Theoretical characterization and exemplified utilization | Type | A1 Journal article | ||
| Year | 2017 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
| Volume |
96 | Issue | 21 | Pages | 214403 |
| Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
| Abstract | <script type='text/javascript'>document.write(unpmarked('Magnetic skyrmions are nanoscale windings of the spin structure that can be observed in chiral magnets and hold promise for potential applications in storing or processing information. Pinning due to ever-present material imperfections crucially affects the mobility of skyrmions. Therefore, a proper understanding of how magnetic skyrmions pin to defects is necessary for the development and performance of spintronic devices. Here we present a fundamental analysis on the interactions of single skyrmions with atomic defects of distinctly different origins, in a Co monolayer on Pt, based on minimum-energy paths considerations and atomic-spin simulations. We first report the preferred pinning loci of the skyrmion as a function of its nominal size and the type of defect being considered, to further reveal the manipulation and \u0022breathing\u0022 of skyrmion core in the vicinity of a defect. We also show the behavior of skyrmions in the presence of an extended defect of particular geometry, that can lead to ratcheted skyrmion motion or a facilitated guidance on a defect \u0022trail.\u0022 We close the study with reflections on the expected thermal stability of the skyrmion against collapse on itself for a given nature of the defect, and discuss the applications where control of skyrmions by defects is of particular interest.')); | ||||
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| Publisher | American Physical Society | Place of Publication | New York, N.Y | Editor | |
| Language | Wos | 000416846900002 | Publication Date | 2017-12-01 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9969; 2469-9950 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 52 | Open Access | |
| Notes | ; This work was supported by the Research Foundation, Flanders (FWO-Vlaanderen) and Brazilian agency CNPq (Grants No. 442668/2014-7 and No. 140840/2016-8). ; | Approved | Most recent IF: 3.836 | ||
| Call Number | UA @ lucian @ c:irua:147684 | Serial | 4890 | ||
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| Author | Zhang, L.-F.; Covaci, L.; Milošević, M.V. | ||||
| Title | Topological phase transitions in small mesoscopic chiral p-wave superconductors | Type | A1 Journal article | ||
| Year | 2017 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
| Volume |
96 | Issue | 22 | Pages | 224512 |
| Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
| Abstract | <script type='text/javascript'>document.write(unpmarked('Spin-triplet chiral p-wave superconductivity is typically described by a two-component order parameter, and as such is prone to unique emergent effects when compared to the standard single-component superconductors. Here we present the equilibrium phase diagram for small mesoscopic chiral p-wave superconducting disks in the presence of magnetic field, obtained by solving the microscopic Bogoliubov-de Gennes equations self-consistently. In the ultrasmall limit, the cylindrically symmetric giant-vortex states form the ground state of the system. However, with increasing sample size, the cylindrical symmetry is broken as the two components of the order parameter segregate into domains, and the number of fragmented domain walls between them characterizes the resulting states. Such domain walls are topological defects unique for the p-wave order, and constitute a dominant phase in the mesoscopic regime. Moreover, we find two possible types of domain walls, identified by their chirality-dependent interaction with the edge states.')); | ||||
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| Publisher | American Physical Society | Place of Publication | New York, N.Y | Editor | |
| Language | Wos | 000418653500012 | Publication Date | 2017-12-26 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9969; 2469-9950 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 18 | Open Access | |
| Notes | ; This work was supported by the Research Foundation Flanders (FWO-Vlaanderen) and the Special Research Funds of the University of Antwerp. ; | Approved | Most recent IF: 3.836 | ||
| Call Number | UA @ lucian @ c:irua:148504 | Serial | 4901 | ||
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| Author | Stosic, D.; Mulkers, J.; Van Waeyenberge, B.; Ludermir, T.B.; Milošević, M.V. | ||||
| Title | Paths to collapse for isolated skyrmions in few-monolayer ferromagnetic films | Type | A1 Journal article | ||
| Year | 2017 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
| Volume |
95 | Issue | 21 | Pages | 214418 |
| Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
| Abstract | Magnetic skyrmions are topological spin configurations in materials with chiral Dzyaloshinskii-Moriya interaction (DMI), that are potentially useful for storing or processing information. To date, DMI has been found in few bulk materials, but can also be induced in atomically thin magnetic films in contact with surfaces with large spin-orbit interactions. Recent experiments have reported that isolated magnetic skyrmions can be stabilized even near room temperature in few-atom-thick magnetic layers sandwiched between materials that provide asymmetric spin-orbit coupling. Here we present the minimum-energy path analysis of three distinct mechanisms for the skyrmion collapse, based on ab initio input and the performed atomic-spin simulations. We focus on the stability of a skyrmion in three atomic layers of Co, either epitaxial on the Pt(111) surface or within a hybrid multilayer where DMI nontrivially varies per monolayer due to competition between different symmetry breaking from two sides of the Co film. In laterally finite systems, their constrained geometry causes poor thermal stability of the skyrmion toward collapse at the boundary, which we show to be resolved by designing the high-DMI structure within an extended film with lower or no DMI. | ||||
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| Language | Wos | 000404015500001 | Publication Date | 2017-06-23 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9950 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 48 | Open Access | |
| Notes | This work was supported by the Research Foundation, Flanders (FWO-Vlaanderen) and Brazilian agency CNPq (Grants No. 442668/2014-7 and No. 140840/2016-8). | Approved | Most recent IF: 3.836 | ||
| Call Number | CMT @ cmt @c:irua:144865 | Serial | 4704 | ||
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| Author | Li, L.L.; Moldovan, D.; Vasilopoulos, P.; Peeters, F.M. | ||||
| Title | Aharonov-Bohm oscillations in phosphorene quantum rings | Type | A1 Journal article | ||
| Year | 2017 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
| Volume |
95 | Issue | 20 | Pages | 205426 |
| Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
| Abstract | The Aharonov-Bohm (AB) effect in square phosphorene quantum rings, with armchair and zigzag edges, is investigated using the tight-binding method. The energy spectra and wave functions of such rings, obtained as a function of the magnetic flux Phi threading the ring, are strongly influenced by the ringwidthW, an in-plane electric field E-p, and a side-gating potential V-g. Compared to a square dot, the ring shows an enhanced confinement due to its inner edges and an interedge coupling along the zigzag direction, both of which strongly affect the energy spectrum and the wave functions. The energy spectrum that is gapped consists of a regular part, of conduction (valence) band states, that shows the usual AB oscillations in the higher-(lower-) energy region, and of edge states, in the gap, that exhibit no AB oscillations. As the width W decreases, the AB oscillations become more distinct and regular and their period is close to Phi(0)/2, where the flux quantum Phi(0) = h/e is the period of an ideal circular ring (W -> 0). Both the electric field E-p and the side-gating potential V-g reduce the amplitude of the AB oscillations. The amplitude can be effectively tuned by E-p or V-g and exhibits an anisotropic behavior for different field directions or side-gating configurations. | ||||
| Address | |||||
| Corporate Author | Thesis | ||||
| Publisher | American Physical Society | Place of Publication | New York, N.Y | Editor | |
| Language | Wos | 000402003700010 | Publication Date | 2017-05-23 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9969; 2469-9950 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 16 | Open Access | |
| Notes | ; This work was financially supported by the Chinese Academy of Sciences, the Flemish Science Foundation (FWO-V1), and by the Canadian NSERC Grant No. OGP0121756 (P.V.). ; | Approved | Most recent IF: 3.836 | ||
| Call Number | UA @ lucian @ c:irua:144267 | Serial | 4638 | ||
| Permanent link to this record | |||||
| Author | Mulkers, J.; Van Waeyenberge, B.; Milošević, M.V. | ||||
| Title | Effects of spatially engineered Dzyaloshinskii-Moriya interaction in ferromagnetic films | Type | A1 Journal article | ||
| Year | 2017 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
| Volume |
95 | Issue | 95 | Pages | 144401 |
| Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
| Abstract | The Dzyaloshinskii-Moriya interaction (DMI) is a chiral interaction that favors formation of domain walls. Recent experiments and ab initio calculations show that there are multiple ways to modify the strength of the interfacially induced DMI in thin ferromagnetic films with perpendicular magnetic anisotropy. In this paper we reveal theoretically the effects of spatially varied DMI on the magnetic state in thin films. In such heterochiral 2D structures we report several emergent phenomena, ranging from the equilibrium spin canting at the interface between regions with different DMI, over particularly strong confinement of domain walls and skyrmions within high-DMI tracks, to advanced applications such as domain tailoring nearly at will, design of magnonic waveguides, and much improved skyrmion racetrack memory. | ||||
| Address | |||||
| Corporate Author | Thesis | ||||
| Publisher | Place of Publication | Editor | |||
| Language | Wos | 000399382100003 | Publication Date | 2017-04-03 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9950 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 60 | Open Access | |
| Notes | Fonds Wetenschappelijk Onderzoek, G098917N ; | Approved | Most recent IF: 3.836 | ||
| Call Number | CMT @ cmt @ c:irua:141917 | Serial | 4534 | ||
| Permanent link to this record | |||||
| Author | Li, L.L.; Zarenia, M.; Xu, W.; Dong, H.M.; Peeters, F.M. | ||||
| Title | Exciton states in a circular graphene quantum dot: Magnetic field induced intravalley to intervalley transition | Type | A1 Journal article | ||
| Year | 2017 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
| Volume |
95 | Issue | 95 | Pages | 045409 |
| Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
| Abstract | The magnetic-field dependence of the energy spectrum, wave function, binding energy, and oscillator strength of exciton states confined in a circular graphene quantum dot (CGQD) is obtained within the configuration interaction method. We predict that (i) excitonic effects are very significant in the CGQD as a consequence of a combination of geometric confinement, magnetic confinement, and reduced screening; (ii) two types of excitons (intravalley and intervalley) are present in the CGQD because of the valley degree of freedom in graphene; (iii) the intravalley and intervalley exciton states display different magnetic-field dependencies due to the different electron-hole symmetries of the single-particle energy spectra; (iv) with increasing magnetic field, the exciton ground state in the CGQD undergoes an intravalley to intervalley transition accompanied by a change of angular momentum; (v) the exciton binding energy does not increase monotonically with the magnetic field due to the competition between geometric and magnetic confinements; and (vi) the optical transitions of the intervalley and intravalley excitons can be tuned by the magnetic field, and valley-dependent excitonic transitions can be realized in a CGQD. | ||||
| Address | |||||
| Corporate Author | Thesis | ||||
| Publisher | Place of Publication | Editor | |||
| Language | Wos | 000391856000006 | Publication Date | 2017-01-12 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9950;2469-9969; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 14 | Open Access | |
| Notes | ; This work was financially supported by the China Scholarship Council (CSC), the Flemish Science Foundation (FWO-Vl), the National Natural Science Foundation of China (Grants No. 11304316, No. 11574319, and No. 11604380), and by the Chinese Academy of Sciences (CAS). ; | Approved | Most recent IF: 3.836 | ||
| Call Number | UA @ lucian @ c:irua:141444 | Serial | 4555 | ||
| Permanent link to this record | |||||
| Author | Satarifard, V.; Mousaei, M.; Hadadi, F.; Dix, J.; Sobrino Fernández, M.; Carbone, P.; Beheshtian, J.; Peeters, F.M.; Neek-Amal, M. | ||||
| Title | Reversible structural transition in nanoconfined ice | Type | A1 Journal article | ||
| Year | 2017 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
| Volume |
95 | Issue | 95 | Pages | 064105 |
| Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
| Abstract | The report on square ice sandwiched between two graphene layers by Algara-Siller et al. [Nature (London) 519, 443 (2015)] has generated a large interest in this system. By applying high lateral pressure on nanoconfined water, we found that monolayer ice is transformed to bilayer ice when the two graphene layers are separated by H = 6,7 angstrom. It was also found that three layers of a denser phase of ice with smaller lattice constant are formed if we start from bilayer ice and apply a lateral pressure of about 0.7 GPa with H = 8,9 angstrom. The lattice constant (2.5-2.6 angstrom) in both transitions is found to be smaller than those typical for the known phases of ice and water, i.e., 2.8 angstrom. We validate these results using ab initio calculations and find good agreement between ab initio O-O distance and those obtained from classical molecular dynamics simulations. The reversibility of the mentioned transitions is confirmed by decompressing the systems. | ||||
| Address | |||||
| Corporate Author | Thesis | ||||
| Publisher | Place of Publication | Editor | |||
| Language | Wos | 000393943300005 | Publication Date | 2017-02-16 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9950;2469-9969; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 23 | Open Access | |
| Notes | ; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Methusalem Foundation. ; | Approved | Most recent IF: 3.836 | ||
| Call Number | UA @ lucian @ c:irua:141994 | Serial | 4558 | ||
| Permanent link to this record | |||||
| Author | Han, F.W.; Xu, W.; Li, L.L.; Zhang, C.; Dong, H.M.; Peeters, F.M. | ||||
| Title | Electronic and transport properties of n-type monolayer black phosphorus at low temperatures | Type | A1 Journal article | ||
| Year | 2017 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
| Volume |
95 | Issue | 95 | Pages | 115436 |
| Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
| Abstract | We present a detailed theoretical study of the electronic and transport properties of monolayer black phosphorus (BP). This study is motivated by recent experimental activities in investigating n-type few-layer BP systems. The electron density of states, the screening length, and the low-temperature electron mobility are calculated for monolayer BP (MLBP). In particular, the electron transport mobilities along the armchair and zigzag directions are examined on the basis of the momentum-balance equation derived from a semiclassical Boltzmann equation. The anisotropic electron mobilities in MLBP along different directions are demonstrated where the electron-impurity scattering is considered. Furthermore, we compare the results obtained from two electronic band structures of MLBP and find that the simplified model can describe quite rightly the electronic and transport properties of MLBP. This study is relevant to the application of few-layer BP based electronic systems as advanced electronic devices. | ||||
| Address | |||||
| Corporate Author | Thesis | ||||
| Publisher | Place of Publication | Editor | |||
| Language | Wos | 000399140700012 | Publication Date | 2017-03-27 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9950 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 12 | Open Access | |
| Notes | National Natural Science Foundation of China, 11574319 11304316 11304317 11604380 ; Ministry of Science and Technology of the People's Republic of China, 2011YQ130018 ; Chinese Academy of Sciences; | Approved | Most recent IF: 3.836 | ||
| Call Number | CMT @ cmt @ c:irua:142431 | Serial | 4564 | ||
| Permanent link to this record | |||||
| Author | Zhao, H.J.; Misko, V.R.; Tempere, J.; Nori, F. | ||||
| Title | Pattern formation in vortex matter with pinning and frustrated intervortex interactions | Type | A1 Journal article | ||
| Year | 2017 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
| Volume |
95 | Issue | 95 | Pages | 104519 |
| Keywords | A1 Journal article; Theory of quantum systems and complex systems; Condensed Matter Theory (CMT) | ||||
| Abstract | We investigate the effects related to vortex-core deformations when vortices approach each other. As a result of these vortex-core deformations, the vortex-vortex interaction effectively acquires an attractive component leading to a variety of vortex patterns typical for systems with nonmonotonic repulsive-attractive interaction, such as stripes and labyrinths. The core deformations are anisotropic and can induce frustration in the vortex-vortex interaction. In turn, this frustration has an impact on the resulting vortex patterns, which are analyzed in the presence of additional random pinning, as a function of the pinning strength. This analysis can be applicable to vortices in multiband superconductors or to vortices in Bose-Einstein condensates. | ||||
| Address | |||||
| Corporate Author | Thesis | ||||
| Publisher | American Physical Society | Place of Publication | New York, N.Y | Editor | |
| Language | Wos | 000399138800006 | Publication Date | 2017-03-30 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9969; 2469-9950 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 5 | Open Access | |
| Notes | ; We acknowledge fruitful discussions with E. Babaev and V. Gladilin. This work is partially supported by the Natural Science Foundation of Jiangsu Province (Grant No. BK20150595), the National Natural Science Foundation of China (Grants No. NSFC-U1432135, No. 11611140101, and No. 11674054), the “Odysseus” program of the Flemish Government and Flemish Research Foundation (FWO-Vl), the Flemish Research Foundation (through Projects No. G.0115.12N, No. G.0119.12N, No. G.0122.12N, and No. G.0429.15N), the Research Fund of the University of Antwerp, the RIKEN iTHES Project, the MURI Center for Dynamic Magneto-Optics via the AFOSR Award No. FA9550-14-1-0040, the IMPACT program of JST, a Grant-in-Aid for Scientific Research (A), the Japan Society for the Promotion of Science (KAKENHI), CREST, and a grant from the John Templeton Foundation. ; | Approved | Most recent IF: 3.836 | ||
| Call Number | UA @ lucian @ c:irua:142429 | Serial | 4602 | ||
| Permanent link to this record | |||||
| Author | Michel, K.H.; Çakir, D.; Sevik, C.; Peeters, F.M. | ||||
| Title | Piezoelectricity in two-dimensional materials : comparative study between lattice dynamics and ab initio calculations | Type | A1 Journal article | ||
| Year | 2017 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
| Volume |
95 | Issue | 95 | Pages | 125415 |
| Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
| Abstract | The elastic constant C-11 and piezoelectric stress constant e(1),(11) of two-dimensional (2D) dielectric materials comprising h-BN, 2H-MoS2, and other transition-metal dichalcogenides and dioxides are calculated using lattice dynamical theory. The results are compared with corresponding quantities obtained with ab initio calculations. We identify the difference between clamped-ion and relaxed-ion contributions with the dependence on inner strains which are due to the relative displacements of the ions in the unit cell. Lattice dynamics allows us to express the inner-strain contributions in terms of microscopic quantities such as effective ionic charges and optoacoustical couplings, which allows us to clarify differences in the piezoelectric behavior between h-BN and MoS2. Trends in the different microscopic quantities as functions of atomic composition are discussed. | ||||
| Address | |||||
| Corporate Author | Thesis | ||||
| Publisher | American Physical Society | Place of Publication | New York, N.Y | Editor | |
| Language | Wos | 000396013400005 | Publication Date | 2017-03-11 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9969; 2469-9950 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 29 | Open Access | |
| Notes | ; The authors acknowledge useful discussions with L. Wirtz and A. Molina-Sanchez. This work was supported by the Methusalem program and the Fonds voor Wetenschappelijk Onderzoek-Vlaanderen. Computational resources were provided by HPC infrastructure of the University of Antwerp (CalcUA), a division of the Flemish Supercomputer Center (VSC), which is funded by the Hercules foundation. ; | Approved | Most recent IF: 3.836 | ||
| Call Number | UA @ lucian @ c:irua:142444 | Serial | 4603 | ||
| Permanent link to this record | |||||
| Author | De Beule, C.; Zarenia, M.; Partoens, B. | ||||
| Title | Transmission in graphene-topological insulator heterostructures | Type | A1 Journal article | ||
| Year | 2017 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
| Volume |
95 | Issue | 95 | Pages | 115424 |
| Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
| Abstract | We investigate scattering of the topological surface state of a three-dimensional time-reversal invariant topological insulator when graphene is deposited on the topological-insulator surface. Specifically, we consider the (111) surface of a Bi2Se3-like topological insulator. We present a low-energy model for the graphene-topological insulator heterostructure and we calculate the transmission probability at zigzag and armchair edges of the deposited graphene, and the conductance through graphene nanoribbon barriers, and show that its features can be understood from antiresonances in the transmission probability. | ||||
| Address | |||||
| Corporate Author | Thesis | ||||
| Publisher | American Physical Society | Place of Publication | New York, N.Y | Editor | |
| Language | Wos | 000399216700004 | Publication Date | 2017-03-22 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9969; 2469-9950 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 4 | Open Access | |
| Notes | ; The authors would like to thank B. Van Duppen for interesting discussions. This work was supported by the Flemish Research Foundation (FWO) through the Aspirant Fellowship of Christophe De Beule. ; | Approved | Most recent IF: 3.836 | ||
| Call Number | UA @ lucian @ c:irua:143652 | Serial | 4609 | ||
| Permanent link to this record | |||||
| Author | de Sousa, G.O.; da Costa, D.R.; Chaves, A.; Farias, G.A.; Peeters, F.M. | ||||
| Title | Unusual quantum confined Stark effect and Aharonov-Bohm oscillations in semiconductor quantum rings with anisotropic effective masses | Type | A1 Journal article | ||
| Year | 2017 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
| Volume |
95 | Issue | 95 | Pages | 205414 |
| Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
| Abstract | The effects of external electric and magnetic fields on the energy spectrum of quantum rings made out of a bidimensional semiconductor material with anisotropic band structures are investigated within the effective-mass model. The interplay between the effective-mass anisotropy and the radial confinement leads to wave functions that are strongly localized at two diametrically opposite regions where the kinetic energy is lowest due to the highest effective mass. We show that this quantum phenomenon has clear consequences on the behavior of the energy states in the presence of applied in-plane electric fields and out-of-plane magnetic fields. In the former, the quantum confined Stark effect is observed with either linear or quadratic shifts, depending on the direction of the applied field. As for the latter, the usual Aharonov-Bohm oscillations are not observed for a circularly symmetric confining potential, however they can be reinstated if an elliptic ring with an appropriate aspect ratio is chosen. | ||||
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| Corporate Author | Thesis | ||||
| Publisher | American Physical Society | Place of Publication | New York, N.Y | Editor | |
| Language | Wos | 000401230600007 | Publication Date | 2017-05-12 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9969; 2469-9950 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 19 | Open Access | |
| Notes | ; This work was financially supported by CNPq under the PRONEX/FUNCAP grants, CAPES Foundation, the Flemish Science Foundation (FWO-Vl), and the Brazilian Program Science Without Borders (CsF). ; | Approved | Most recent IF: 3.836 | ||
| Call Number | UA @ lucian @ c:irua:143746 | Serial | 4610 | ||
| Permanent link to this record | |||||
| Author | Zarenia, M.; Neilson, D.; Partoens, B.; Peeters, F.M. | ||||
| Title | Wigner crystallization in transition metal dichalcogenides : a new approach to correlation energy | Type | A1 Journal article | ||
| Year | 2017 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
| Volume |
95 | Issue | 95 | Pages | 115438 |
| Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
| Abstract | We introduce a new approach for the correlation energy of one- and two-valley two-dimensional electron gas (2DEG) systems. Our approach is based on an interpolation between two limits, a random phase approximation at high densities and a classical approach at low densities which gives excellent agreement with available Quantum Monte Carlo (QMC) calculations. The two-valley 2DEG model is introduced to describe the electron correlations in monolayer transition metal dichalcogenides (TMDs). We study the zero-temperature transition from a Fermi liquid to a quantum Wigner crystal phase in monolayer TMDs. Consistent with QMC, we find that electrons crystallize at r(s) = 31 in one-valley 2DEG. For two valleys, we predict Wigner crystallization at r(s) = 30, implying that valley degeneracy has little effect on the critical r(s), in contrast to an earlier claim. | ||||
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| Corporate Author | Thesis | ||||
| Publisher | American Physical Society | Place of Publication | New York, N.Y | Editor | |
| Language | Wos | 000399141200003 | Publication Date | 2017-03-30 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9969; 2469-9950 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 18 | Open Access | |
| Notes | ; This work was partially supported by the Flanders Research Foundation (FWO) and the Methusalem program of the Flemish government. D.N. acknowledges support by the University of Camerino FAR project CESEMN. ; | Approved | Most recent IF: 3.836 | ||
| Call Number | UA @ lucian @ c:irua:142428 | Serial | 4613 | ||
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| Author | Van Pottelberge, R.; Zarenia, M.; Vasilopoulos, P.; Peeters, F.M. | ||||
| Title | Graphene quantum dot with a Coulomb impurity : subcritical and supercritical regime | Type | A1 Journal article | ||
| Year | 2017 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
| Volume |
95 | Issue | 24 | Pages | 245410 |
| Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
| Abstract | We study the influence of confinement on the atomic collapse due to a Coulomb impurity placed at the center of a graphene quantum dot of radius R. We apply the zigzag or infinite-mass boundary condition and consider both a point-size and a finite-size impurity. As a function of the impurity strength Za, the energy spectra are discrete. In the case of the zigzag boundary condition, the degenerate (with respect to the angular momentum m) zero-energy levels are pulled down in energy as Z alpha increases, and they remain below epsilon = – Z alpha. Our results show that the energy levels exhibit a 1/R dependence in the subcritical regime [Z alpha < |km + 1/2|, k = 1 (-1) for the K (K') valley]. In the supercritical regime (Z alpha > |km + 1/2|) we find a qualitatively very different behavior where the levels decrease as a function of R in a nonmonotonic manner. While the valley symmetry is preserved in the presence of the impurity, we find that the impurity breaks electron-hole symmetry. We further study the energy spectrum of zigzag quantum dots in gapped graphene. Our results show that as the gap increases, the lowest electron states are pushed into the gap by the impurity. | ||||
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| Corporate Author | Thesis | ||||
| Publisher | American Physical Society | Place of Publication | New York, N.Y | Editor | |
| Language | Wos | 000403072400005 | Publication Date | 2017-06-13 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9969; 2469-9950 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 13 | Open Access | |
| Notes | ; We thank Massoud Ramezani-Masir and Dean Moldovan for fruitful discussions. This work was supported by the Flemish Science Foundation (FWO-Vl), the Methusalem funding of the Flemish Government, and by the Canadian NSERC Grant No. OGP0121756 (P. V.). ; | Approved | Most recent IF: 3.836 | ||
| Call Number | UA @ lucian @ c:irua:144197 | Serial | 4661 | ||
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| Author | Houben, K.; Couet, S.; Trekels, M.; Menendez, E.; Peissker, T.; Seo, J.W.; Hu, M.Y.; Zhao, J.Y.; Alp, E.E.; Roelants, S.; Partoens, B.; Milošević, M.V.; Peeters, F.M.; Bessas, D.; Brown, S.A.; Vantomme, A.; Temst, K.; Van Bael, M.J. | ||||
| Title | Lattice dynamics in Sn nanoislands and cluster-assembled films | Type | A1 Journal article | ||
| Year | 2017 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
| Volume |
95 | Issue | 15 | Pages | 155413 |
| Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
| Abstract | To unravel the effects of phonon confinement, the influence of size and morphology on the atomic vibrations is investigated in Sn nanoislands and cluster-assembled films. Nuclear resonant inelastic x-ray scattering is used to probe the phonon densities of states of the Sn nanostructures which show significant broadening of the features compared to bulk phonon behavior. Supported by ab initio calculations, the broadening is attributed to phonon scattering and can be described within the damped harmonic oscillator model. Contrary to the expectations based on previous research, the appearance of high-energy modes above the cutoff energy is not observed. From the thermodynamic properties extracted from the phonon densities of states, it was found that grain boundary Sn atoms are bound by weaker forces than bulk Sn atoms. | ||||
| Address | |||||
| Corporate Author | Thesis | ||||
| Publisher | American Physical Society | Place of Publication | New York, N.Y | Editor | |
| Language | Wos | 000401762400008 | Publication Date | 2017-04-11 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9969; 2469-9950 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 5 | Open Access | |
| Notes | ; This work was supported by the Research Foundation-Flanders (FWO) and the Concerted Research Action (GOA/14/007). The authors acknowledge Hercules stichting (Projects No. AKUL/13/19 and No. AKUL/13/25). K.H. and S.C. thank the FWO for financial support. T.P. acknowledges the IWT for financial support. S.R., M.V.M., and B.P. acknowledge TOPBOF funding of the University of Antwerp Research Fund. J.W.S. acknowledges Hercules Stichting (Project No. AKUL/13/19). The authors want to thank R. Lieten for help with the XRD measurements and T. Picot for fruitful discussions. The authors gratefully acknowledge R. Ruffer and A. I. Chumakov for fruitful discussions and the European Synchrotron Radiation Facility for the measurement of the SnO<INF>2</INF> powder at the Nuclear Resonance beamline (ID-18). This research used resources of the Advanced Photon Source, a US Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. ; | Approved | Most recent IF: 3.836 | ||
| Call Number | UA @ lucian @ c:irua:144305 | Serial | 4667 | ||
| Permanent link to this record | |||||
| Author | Kleibert, A.; Balan, A.; Yanes, R.; Derlet, P.M.; Vaz, C.A.F.; Timm, M.; Fraile Rodríguez, A.; Béché, A.; Verbeeck, J.; Dhaka, R.S.; Radovic, M.; Nowak, U.; Nolting, F. | ||||
| Title | Direct observation of enhanced magnetism in individual size- and shape-selected 3d transition metal nanoparticles | Type | A1 Journal article | ||
| Year | 2017 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
| Volume |
95 | Issue | 95 | Pages | 195404 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | Magnetic nanoparticles are critical building blocks for future technologies ranging from nanomedicine to spintronics. Many related applications require nanoparticles with tailored magnetic properties. However, despite significant efforts undertaken towards this goal, a broad and poorly understood dispersion of magnetic properties is reported, even within monodisperse samples of the canonical ferromagnetic 3d transition metals. We address this issue by investigating the magnetism of a large number of size- and shape-selected, individual nanoparticles of Fe, Co, and Ni using a unique set of complementary characterization techniques. At room temperature, only superparamagnetic behavior is observed in our experiments for all Ni nanoparticles within the investigated sizes, which range from 8 to 20 nm. However, Fe and Co nanoparticles can exist in two distinct magnetic states at any size in this range: (i) a superparamagnetic state, as expected from the bulk and surface anisotropies known for the respective materials and as observed for Ni, and (ii) a state with unexpected stable magnetization at room temperature. This striking state is assigned to significant modifications of the magnetic properties arising from metastable lattice defects in the core of the nanoparticles, as concluded by calculations and atomic structural characterization. Also related with the structural defects, we find that the magnetic state of Fe and Co nanoparticles can be tuned by thermal treatment enabling one to tailor their magnetic properties for applications. This paper demonstrates the importance of complementary single particle investigations for a better understanding of nanoparticle magnetism and for full exploration of their potential for applications. | ||||
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| Publisher | Place of Publication | Editor | |||
| Language | Wos | 000400665300002 | Publication Date | 2017-05-05 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9950 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 21 | Open Access | OpenAccess |
| Notes | We thank A. Weber, R. Schelldorfer, and J. Krbanjevic (Paul Scherrer Institut) for technical assistance. This paper was supported by the Swiss Nanoscience Institute, University of Basel. A.F.R. acknowledges support from the MICIIN “Ramón y Cajal” Programme. A.B. and J.V. acknowledge funding from the European Union under the European Research Council (ERC) Starting Grant No. 278510 VORTEX and under a contract for Integrated Infrastructure Initiative ESTEEM2 No. 312483. R.Y. and U.N. thank the Deutsche Forschungsgemeinschaft for financial support via Sonderforschungsbereich 1214. Part of this work was performed at the Surface/Interface: Microscopy (SIM) beamline of the Swiss Light Source, Paul Scherrer Institut, Villigen, Switzerland. | Approved | Most recent IF: 3.836 | ||
| Call Number | EMAT @ emat @ c:irua:143634UA @ admin @ c:irua:143634 | Serial | 4575 | ||
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| Author | da Costa; Zarenia, M.; Chaves, A.; Pereira, J.M., Jr.; Farias, G.A.; Peeters, F.M. | ||||
| Title | Hexagonal-shaped monolayer-bilayer quantum disks in graphene : a tight-binding approach | Type | A1 Journal article | ||
| Year | 2016 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
| Volume |
94 | Issue | 94 | Pages | 035415 |
| Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
| Abstract | Using the tight-binding approach, we investigate confined states in two different hybrid monolayer-bilayer systems: (i) a hexagonal monolayer area surrounded by bilayer graphene in the presence of a perpendicularly applied electric field and (ii) a hexagonal bilayer graphene dot surrounded by monolayer graphene. The dependence of the energy levels on dot size and external magnetic field is calculated. We find that the energy spectrum for quantum dots with zigzag edges consists of states inside the gap which range from dot-localized states, edge states, to mixed states coexisting together, whereas for dots with armchair edges, only dot-localized states are observed. | ||||
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| Publisher | Place of Publication | Editor | |||
| Language | Wos | 000379502200008 | Publication Date | 2016-07-11 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9950;2469-9969; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 11 | Open Access | |
| Notes | ; This work was financially supported by CNPq, under contract NanoBioEstruturas No. 555183/2005-0, PRONEX/FUNCAP, CAPES Foundation, under the process No. BEX 7178/13-1, the Flemish Science Foundation (FWO-Vl), the Bilateral programme between CNPq and FWO-Vl, the Brazilian Program Science Without Borders (CsF), and the Lemann Foundation. ; | Approved | Most recent IF: 3.836 | ||
| Call Number | UA @ lucian @ c:irua:134947 | Serial | 4190 | ||
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| Author | Zhao, H.J.; Wu, W.; Zhou, W.; Shi, Z.X.; Misko, V.R.; Peeters, F.M. | ||||
| Title | Reentrant dynamics of driven pancake vortices in layered superconductors | Type | A1 Journal article | ||
| Year | 2016 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
| Volume |
94 | Issue | 94 | Pages | 024514 |
| Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
| Abstract | The dynamics of driven pancake vortices in layered superconductors is studied using molecular-dynamics simulations. We found that, with increasing driving force, for strong interlayer coupling, the preexisted vortex lines either directly depin or first transform to two-dimensional (2D) pinned states before they are depinned, depending on the pinning strength. In a narrow region of pinning strengths, we found an interesting repinning process, which results in a negative differential resistance. For weak interlayer coupling, individually pinned pancake vortices first form disordered 2D flow and then transform to ordered three-dimensional (3D) flow with increasing driving force. However, for extremely strong pinning, the random pinning-induced thermal-like Langevin forces melt 3D vortex lines, which results in a persistent 2D flow in the fast-sliding regime. In the intermediate regime, the peak effect is found: With increasing driving force, the moving pancake vortices first crystallize to moving 3D vortex lines, and then these 3D vortex lines are melted, leading to the appearance of a reentrant 2D flow state. Our results are summarized in a dynamical phase diagram. | ||||
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| Corporate Author | Thesis | ||||
| Publisher | Place of Publication | Editor | |||
| Language | Wos | 000380097800006 | Publication Date | 2016-07-18 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9950;2469-9969; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 3 | Open Access | |
| Notes | ; We acknowledge useful discussions with C. Olson Reichhardt. This work was supported by the Natural Science Foundation of Jiangsu Province (Grant No. BK20150595), National Natural Science Foundation of China (Grants No. NSFC-U1432135 and No. 11611140101). V.R.M. acknowledges support from the “Odysseus” program of the Flemish Government and Flemish Science Foundation (FWO-Vl), the FWO-Vl, and the Research Fund of the University of Antwerp. ; | Approved | Most recent IF: 3.836 | ||
| Call Number | UA @ lucian @ c:irua:134943 | Serial | 4238 | ||
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| Author | Zhang, L.; Fernández Becerra, V.; Covaci, L.; Milošević, M.V. | ||||
| Title | Electronic properties of emergent topological defects in chiral p-wave superconductivity | Type | A1 Journal article | ||
| Year | 2016 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
| Volume |
94 | Issue | 94 | Pages | 024520 |
| Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
| Abstract | Chiral p-wave superconductors in applied magnetic field can exhibit more complex topological defects than just conventional superconducting vortices, due to the two-component order parameter (OP) and the broken time-reversal symmetry. We investigate the electronic properties of those exotic states, some of which contain clusters of one-component vortices in chiral components of the OP and/or exhibit skyrmionic character in the relative OP space, all obtained as a self-consistent solution of the microscopic Bogoliubov-de Gennes equations. We reveal the link between the local density of states (LDOS) of the novel topological states and the behavior of the chiral domain wall between the OP components, enabling direct identification of those states in scanning tunneling microscopy. For example, a skyrmion always contains a closed chiral domain wall, which is found to be mapped exactly by zero-bias peaks in LDOS. Moreover, the LDOS exhibits electron-hole asymmetry, which is different from the LDOS of conventional vortex states with same vorticity. Finally, we present the magnetic field and temperature dependence of the properties of a skyrmion, indicating that this topological defect can be surprisingly large in size, and can be pinned by an artificially indented nonsuperconducting closed path in the sample. These features are expected to facilitate the experimental observation of skyrmionic states, thereby enabling experimental verification of chirality in emerging superconducting materials. | ||||
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| Corporate Author | Thesis | ||||
| Publisher | American Physical Society | Place of Publication | New York, N.Y | Editor | |
| Language | Wos | 000381479500002 | Publication Date | 2016-07-26 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9969 | 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 Fonds Wetenschappelijk Onderzoek (FWO). ; | Approved | Most recent IF: 3.836 | ||
| Call Number | UA @ lucian @ c:irua:135742 | Serial | 4303 | ||
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| Author | Sisakht, E.T.; Fazileh, F.; Zare, M.H.; Zarenia, M.; Peeters, F.M. | ||||
| Title | Strain-induced topological phase transition in phosphorene and in phosphorene nanoribbons | Type | A1 Journal article | ||
| Year | 2016 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
| Volume |
94 | Issue | 94 | Pages | 085417 |
| Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
| Abstract | Using the tight-binding (TB) approximation with inclusion of the spin-orbit interaction, we predict a topological phase transition in the electronic band structure of phosphorene in the presence of axial strains. We derive a low-energy TB Hamiltonian that includes the spin-orbit interaction for bulk phosphorene. Applying a compressive biaxial in-plane strain and perpendicular tensile strain in ranges where the structure is still stable leads to a topological phase transition. We also examine the influence of strain on zigzag phosphorene nanoribbons (zPNRs) and the formation of the corresponding protected edge states when the system is in the topological phase. For zPNRs up to a width of 100 nm the energy gap is at least three orders of magnitude larger than the thermal energy at room temperature. | ||||
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| Publisher | Place of Publication | Editor | |||
| Language | Wos | 000381600800004 | Publication Date | 2016-08-18 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9950;2469-9969; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 76 | Open Access | |
| Notes | ; This work was supported by Ministry of Science, Research and Technology, Iran. M.Z. acknowledges support as a postdoctoral fellow of the Flemish Research Foundation (FWO-Vl). ; | Approved | Most recent IF: 3.836 | ||
| Call Number | UA @ lucian @ c:irua:135643 | Serial | 4309 | ||
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| Author | Bekaert, J.; Vercauteren, S.; Aperis, A.; Komendová, L.; Prozorov, R.; Partoens, B.; Milošević, M.V. | ||||
| Title | Anisotropic type-I superconductivity and anomalous superfluid density in OsB2 | Type | A1 Journal article | ||
| Year | 2016 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
| Volume |
94 | Issue | 94 | Pages | 144506 |
| Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
| Abstract | We present a microscopic study of superconductivity in OsB2 , and discuss the origin and characteristic length scales of the superconducting state. From first-principles we show that OsB2 is characterized by three different Fermi sheets, and we prove that this fermiology complies with recent quantum-oscillation experiments. Using the found microscopic properties, and experimental data from the literature, we employ Ginzburg-Landau relations to reveal that OsB2 is a distinctly type-I superconductor with a very low Ginzburg-Landau parameter κ—a rare property among compound materials. We show that the found coherence length and penetration depth corroborate the measured thermodynamic critical field. Moreover, our calculation of the superconducting gap structure using anisotropic Eliashberg theory and ab initio calculated electron-phonon interaction as input reveals a single but anisotropic gap. The calculated gap spectrum is shown to give an excellent account for the unconventional behavior of the superfluid density of OsB2 measured in experiments as a function of temperature. This reveals that gap anisotropy can explain such behavior, observed in several compounds, which was previously attributed solely to a two-gap nature of superconductivity. |
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| Publisher | Place of Publication | Editor | |||
| Language | Wos | 000385622500009 | Publication Date | 2016-10-12 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9950 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 19 | Open Access | |
| Notes | Fonds Wetenschappelijk Onderzoek; European Cooperation in Science and Technology, MP1201 ; Vetenskapsrådet; | Approved | Most recent IF: 3.836 | ||
| Call Number | CMT @ cmt @ c:irua:139020 | Serial | 4338 | ||
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