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Author Michel, K.H.; Scuracchio, P.; Peeters, F.M. url  doi
openurl 
  Title Sound waves and flexural mode dynamics in two-dimensional crystals Type A1 Journal article
  Year 2017 Publication (down) Physical review B Abbreviated Journal Phys Rev B  
  Volume 96 Issue 9 Pages 094302  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract Starting from a Hamiltonian with anharmonic coupling between in-plane acoustic displacements and outof-plane (flexural) modes, we derived coupled equations of motion for in-plane displacements correlations and flexural mode density fluctuations. Linear response theory and time-dependent thermal Green's functions techniques are applied in order to obtain different response functions. As external perturbations we allow for stresses and thermal heat sources. The displacement correlations are described by a Dyson equation where the flexural density distribution enters as an additional perturbation. The flexural density distribution satisfies a kinetic equation where the in-plane lattice displacements act as a perturbation. In the hydrodynamic limit this system of coupled equations is at the basis of a unified description of elastic and thermal phenomena, such as isothermal versus adiabatic sound motion and thermal conductivity versus second sound. The general theory is formulated in view of application to graphene, two-dimensional h-BN, and 2H-transition metal dichalcogenides and oxides.  
  Address  
  Corporate Author Thesis  
  Publisher American Physical Society Place of Publication New York, N.Y Editor  
  Language Wos 000409246200003 Publication Date 2017-09-05  
  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 Flemish Science Foundation (FWO-Vl) and the Methusalem program. ; Approved Most recent IF: 3.836  
  Call Number UA @ lucian @ c:irua:145630 Serial 4751  
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Author Saberi-Pouya, S.; Vazifehshenas, T.; Salavati-Fard, T.; Farmanbar, M.; Peeters, F.M. url  doi
openurl 
  Title Strong anisotropic optical conductivity in two-dimensional puckered structures : the role of the Rashba effect Type A1 Journal article
  Year 2017 Publication (down) Physical review B Abbreviated Journal Phys Rev B  
  Volume 96 Issue 7 Pages 075411  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract within the Kubo formalism. We show that the anisotropic Rashba effect caused by an external field significantly changes the magnitude of the spin splitting. Furthermore, we obtain an analytical expression for the longitudinal optical conductivity associated with interband transitions as a function of the frequency for arbitrary polarization angle. We find that the diagonal components of the optical conductivity tensor are direction dependent and the optical absorption spectrum exhibits a strongly anisotropic absorption window. The height and width of this absorption window are very sensitive to the anisotropy of the system. While the height of absorption peak increases with increasing effective mass anisotropy ratio, the peak intensity is larger when the light polarization is along the armchair direction. Moreover, the absorption peak width becomes broader as the density-of-states mass or Rashba interaction is enhanced. These features in the optical absorption spectrum can be used to determine parameters relevant for spintronics.  
  Address  
  Corporate Author Thesis  
  Publisher American Physical Society Place of Publication New York, N.Y Editor  
  Language Wos 000407097100005 Publication Date 2017-08-09  
  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 ; ; Approved Most recent IF: 3.836  
  Call Number UA @ lucian @ c:irua:145725 Serial 4752  
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Author Rezaei, M.; Sisakht, E.T.; Fazileh, F.; Aslani, Z.; Peeters, F.M. url  doi
openurl 
  Title Tight-binding model investigation of the biaxial strain induced topological phase transition in GeCH3 Type A1 Journal article
  Year 2017 Publication (down) 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.  
  Address  
  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. url  doi
openurl 
  Title Spin-reorientation transitions in the Cairo pentagonal magnet Bi4Fe5O13F Type A1 Journal article
  Year 2017 Publication (down) 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.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  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. url  doi
openurl 
  Title Electronic properties of bilayer phosphorene quantum dots in the presence of perpendicular electric and magnetic fields Type A1 Journal article
  Year 2017 Publication (down) 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.  
  Address  
  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. url  doi
openurl 
  Title Landau levels in biased graphene structures with monolayer-bilayer interfaces Type A1 Journal article
  Year 2017 Publication (down) Physical review B Abbreviated Journal Phys Rev B  
  Volume 96 Issue 12 Pages 125430  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract The electron energy spectrum in monolayer-bilayer-monolayer and in bilayer-monolayer-bilayer graphene structures is investigated and the effects of a perpendicular magnetic field and electric bias are studied. Different types of monolayer-bilayer interfaces are considered as zigzag (ZZ) or armchair (AC) junctions which modify considerably the bulk Landau levels (LLs) when the spectra are plotted as a function of the center coordinate of the cyclotron orbit. Far away from the two interfaces, one obtains the well-known LLs for extended monolayer or bilayer graphene. The LL structure changes significantly at the two interfaces or junctions where the valley degeneracy is lifted for both types of junctions, especially when the distance between them is approximately equal to the magnetic length. Varying the nonuniform bias and the width of this junction-to-junction region in either structure strongly influence the resulting spectra. Significant differences exist between ZZ and AC junctions in both structures. The densities of states (DOSs) for unbiased structures are symmetric in energy whereas those for biased structures are asymmetric. An external bias creates interface LLs in the gaps between the LLs of the unbiased system in which the DOS can be quite small. Such a pattern of LLs can be probed by scanning tunneling microscopy.  
  Address  
  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. url  doi
openurl 
  Title Magnetic properties of bilayer graphene quantum dots in the presence of uniaxial strain Type A1 Journal article
  Year 2017 Publication (down) 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.  
  Address  
  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. url  doi
openurl 
  Title Multifaceted impact of a surface step on superconductivity in atomically thin films Type A1 Journal article
  Year 2017 Publication (down) 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.  
  Address  
  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. url  doi
openurl 
  Title Normal and skewed phosphorene nanoribbons in combined magnetic and electric fields Type A1 Journal article
  Year 2017 Publication (down) 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.  
  Address  
  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. url  doi
openurl 
  Title Evidence of tetragonal distortion as the origin of the ferromagnetic ground state in gamma-Fe nanoparticles Type A1 Journal article
  Year 2017 Publication (down) 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.'));  
  Address  
  Corporate Author Thesis  
  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. url  doi
openurl 
  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 (down) 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.'));  
  Address  
  Corporate Author Thesis  
  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. url  doi
openurl 
  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 (down) 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.'));  
  Address  
  Corporate Author Thesis  
  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. url  doi
openurl 
  Title Topological phase transitions in small mesoscopic chiral p-wave superconductors Type A1 Journal article
  Year 2017 Publication (down) 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.'));  
  Address  
  Corporate Author Thesis  
  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 Takatsu, H.; Hernandez, O.; Yoshimune, W.; Prestipino, C.; Yamamoto, T.; Tassel, C.; Kobayashi, Y.; Batuk, D.; Shibata, Y.; Abakumov, A.M.; Brown, C.M.; Kageyama, H. doi  openurl
  Title Cubic lead perovskite PbMoO3 with anomalous metallic behavior Type A1 Journal article
  Year 2017 Publication (down) Physical review B Abbreviated Journal  
  Volume 95 Issue 15 Pages 155105  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract A previously unreported Pb-based perovskite PbMoO3 is obtained by high-pressure and high-temperature synthesis. This material crystallizes in the Pm3m cubic structure at room temperature, making it distinct from typical Pb-based perovskite oxides with a structural distortion. PbMoO3 exhibits a metallic behavior down to 0.1 K with an unusual T-sublinear dependence of the electrical resistivity. Moreover, a large specific heat is observed at low temperatures accompanied by a peak in C-P/T-3 around 10 K, in marked contrast to the isostructural metallic system SrMoO3. These transport and thermal properties for PbMoO3, taking into account anomalously large Pb atomic displacements detected through diffraction experiments, are attributed to a low-energy vibrational mode, associated with incoherent off-centering of lone-pair Pb2+ cations. We discuss the unusual behavior of the electrical resistivity in terms of a polaronlike conduction, mediated by the strong coupling between conduction electrons and optical phonons of the local low-energy vibrational mode.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000440605700001 Publication Date 2017-04-04  
  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 Times cited Open Access  
  Notes Approved no  
  Call Number UA @ admin @ c:irua:167288 Serial 7743  
Permanent link to this record
 

 
Author Mirzakhani, M.; Zarenia, M.; Vasilopoulos, P.; Peeters, F.M. doi  openurl
  Title Electrostatically confined trilayer graphene quantum dots Type A1 Journal article
  Year 2017 Publication (down) Physical review B Abbreviated Journal  
  Volume 95 Issue 15 Pages 155434  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract Electrically gating of trilayer graphene (TLG) opens a band gap offering the possibility to electrically engineer TLG quantum dots. We study the energy levels of such quantum dots and investigate their dependence on a perpendicular magnetic field B and different types of stacking of the graphene layers. The dots are modeled as circular and confined by a truncated parabolic potential which can be realized by nanostructured gates or position-dependent doping. The energy spectra exhibit the intervalley symmetry E-K(e) (m) = -E (h)(K') (m) for the electron (e) and hole (h) states, where m is the angular momentum quantum number and K and K' label the two valleys. The electron and hole spectra for B = 0 are twofold degenerate due to the intervalley symmetry E-K (m) = E-K' [-(m + 1)]. For both ABC [alpha = 1.5 (1.2) for large (small) R] and ABA (alpha = 1) stackings, the lowest-energy levels show approximately a R-alpha dependence on the dot radius R in contrast with the 1/R-3 one for ABC-stacked dots with infinite-mass boundary. As functions of the field B, the oscillator strengths for dipole-allowed transitions differ drastically for the two types of stackings.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000399797200003 Publication Date 2017-04-22  
  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 Times cited 6 Open Access  
  Notes Approved no  
  Call Number UA @ admin @ c:irua:152652 Serial 7878  
Permanent link to this record
 

 
Author Shayeganfar, F.; Vasu, K.S.; Nair, R.R.; Peeters, F.M.; Neek-Amal, M. url  doi
openurl 
  Title Monolayer alkali and transition-metal monoxides : MgO, CaO, MnO, and NiO Type A1 Journal article
  Year 2017 Publication (down) Physical review B Abbreviated Journal  
  Volume 95 Issue 14 Pages 144109  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract Two-dimensional crystals with strong interactions between layers has attracted increasing attention in recent years in a variety of fields. In particular, the growth of a single layer of oxide materials (e.g., MgO, CaO, NiO, and MnO) over metallic substrates were found to display different physical properties than their bulk. In this study, we report on the physical properties of a single layer of metallic oxide materials and compare their properties with their bulk and other two-dimensional (2D) crystals. We found that the planar structure of metallic monoxides are unstable whereas the buckled structures are thermodynamically stable. Also, the 2D-MnO and NiO exhibit different magnetic (ferromagnetic) and optical properties than their bulk, whereas band-gap energy and linear stiffness are found to be decreasing from NiO to MgO. Our findings provide insight into oxide thin-film technology applications.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000399792400001 Publication Date 2017-04-20  
  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 Times cited 21 Open Access  
  Notes Approved no  
  Call Number UA @ admin @ c:irua:152654 Serial 8278  
Permanent link to this record
 

 
Author Lu, A.K.A.; Houssa, M.; Luisier, M.; Pourtois, G. url  doi
openurl 
  Title Impact of layer alignment on the behavior of MoS2-ZrS2 tunnel field-effect transistors : an ab initio study Type A1 Journal article
  Year 2017 Publication (down) Physical review applied Abbreviated Journal Phys Rev Appl  
  Volume 8 Issue 3 Pages 034017  
  Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)  
  Abstract Tunnel field-effect transistors based on van der Waals heterostructures are emerging device concepts for low-power applications, auguring sub-60 mV/dec subthreshold swing values. In these devices, the channel is built from a stack of several different two-dimensional materials whose nature allows tailoring the band alignments and enables a good electrostatic control of the device. In this work, we propose a theoretical study of the variability of the performances of a MoS2-ZrS2 tunnel field-effect transistor induced by fluctuations of the relative position or the orientation of the layers. Our results indicate that although a steep subthreshold slope (20 mV/dec) is achievable, fluctuations in the relative orientation of the ZrS2 layer with respect to the MoS2 one lead to a significant variability in the tunneling current by about one decade. This arises from changes in the orbital overlap between the layers and from the modulation of the transport direction.  
  Address  
  Corporate Author Thesis  
  Publisher American Physical Society Place of Publication College Park, Md Editor  
  Language Wos 000411460400001 Publication Date 2017-09-22  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2331-7019 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 4.808 Times cited 6 Open Access OpenAccess  
  Notes Approved Most recent IF: 4.808  
  Call Number UA @ lucian @ c:irua:146741 Serial 4785  
Permanent link to this record
 

 
Author Matsubara, M.; Saniz, R.; Partoens, B.; Lamoen, D. pdf  url
doi  openurl
  Title Doping anatase TiO2with group V-b and VI-b transition metal atoms: a hybrid functional first-principles study Type A1 Journal article
  Year 2017 Publication (down) Physical chemistry, chemical physics Abbreviated Journal Phys Chem Chem Phys  
  Volume 19 Issue 19 Pages 1945-1952  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)  
  Abstract We investigate the role of transition metal atoms of group V-b (V, Nb, Ta) and VI-b (Cr, Mo, W) as n- or p-type dopants in anatase TiO$2$ using thermodynamic

principles and density functional theory with the Heyd-Scuseria-Ernzerhof HSE06 hybrid functional. The HSE06 functional provides a realistic value for the band gap, which ensures a correct classification of dopants as shallow or deep donors or acceptors. Defect formation energies and thermodynamic transition levels are calculated taking into account the constraints imposed by the stability of TiO$
2$ and the solubility limit of the impurities.

Nb, Ta, W and Mo are identified as shallow donors. Although W provides two electrons, Nb and Ta show a considerable lower formation energy, in particular under O-poor conditions. Mo donates in principle one electron, but under specific conditions can turn into a double donor. V impurities are deep donors and Cr

shows up as an amphoteric defect, thereby acting as an electron trapping center in n-type TiO$_2$ especially under O-rich conditions. A comparison with the available experimental data yields excellent agreement.
 
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000394426400027 Publication Date 2016-12-12  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1463-9076 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 4.123 Times cited 19 Open Access OpenAccess  
  Notes We gratefully acknowledge financial support from the IWTVlaanderenthrough projects G.0191.08 and G.0150.13, and the BOF-NOI of the University of Antwerp. This work was carried out using the HPC infrastructure of the University of Antwerp (CalcUA), a division of the Flemish Supercomputer Center VSC, which is funded by the Hercules foundation. M. M. acknowledges financial support from the GOA project ‘‘XANES meets ELNES’’ of the University of Antwerp. Approved Most recent IF: 4.123  
  Call Number EMAT @ emat @ c:irua:140835 Serial 4421  
Permanent link to this record
 

 
Author Saniz, R.; Bekaert, J.; Partoens, B.; Lamoen, D. pdf  url
doi  openurl
  Title Structural and electronic properties of defects at grain boundaries in CuInSe2 Type A1 Journal article
  Year 2017 Publication (down) Physical chemistry, chemical physics Abbreviated Journal Phys Chem Chem Phys  
  Volume 19 Issue 19 Pages 14770-14780  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)  
  Abstract We report on a first-principles study of the structural and electronic properties of a Sigma3 (112) grain boundary model in CuInSe2. The study focuses on a coherent, stoichiometry preserving, cation–Se terminated grain boundary, addressing the properties of the grain boundary as such, as well as the effect

of well known defects in CuInSe2. We show that in spite of its apparent simplicity, such a grain boundary exhibits a very rich phenomenology, providing an explanation for several of the experimentally observed properties of grain boundaries in CuInSe2 thin films. In particular, we show that the combined effect of Cu vacancies and cation antisites can result in the observed Cu depletion with no In enrichment at the grain boundaries. Furthermore, Cu vacancies are unlikely to produce a hole barrier at the grain boundaries, but Na may indeed have such an effect. We find that Na-on-Cu defects will tend to form abundantly at

the grain boundaries, and can provide a mechanism for the carrier depletion and/or type inversion experimentally reported.
 
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000403327200059 Publication Date 2017-05-12  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1463-9076 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 4.123 Times cited 12 Open Access OpenAccess  
  Notes We thank B. Schoeters for his assistance running the GBstudio software. We acknowledge the financial support of FWO-Vlaanderen through project G.0150.13. The computational resources and services used in this work were provided by the VSC (Flemish Supercomputer Center) and the HPC infrastructure of the University of Antwerp (CalcUA), both funded by FWO-Vlaanderen and the Flemish Government-department EWI. Approved Most recent IF: 4.123  
  Call Number EMAT @ emat @ c:irua:143869 Serial 4577  
Permanent link to this record
 

 
Author Shirazi, M.; Bogaerts, A.; Neyts, E.C. pdf  url
doi  openurl
  Title A DFT study of H-dissolution into the bulk of a crystalline Ni(111) surface: a chemical identifier for the reaction kinetics Type A1 Journal article
  Year 2017 Publication (down) Physical chemistry, chemical physics Abbreviated Journal Phys Chem Chem Phys  
  Volume 19 Issue 19 Pages 19150-19158  
  Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)  
  Abstract In this study, we investigated the diffusion of H-atoms to the subsurface and their further diffusion into the bulk of a Ni(111) crystal by means of density functional theory calculations in the context of thermal and plasma-assisted catalysis. The H-atoms at the surface can originate from the dissociative adsorption of H2 or CH4 molecules, determining the surface H-coverage. When a threshold H-coverage is passed, corresponding to 1.00 ML for the crystalline Ni(111) surface, the surface-bound H-atoms start to diffuse to the subsurface. A similar threshold coverage is observed for the interstitial H-coverage. Once the interstitial sites are filled up with a coverage above 1.00 ML of H, dissolution of interstitial H-atoms to the layer below the interstitial sites will be initiated. Hence, by applying a high pressure or inducing a reactive plasma and high temperature, increasing the H-flux to the surface, a large amount of hydrogen can diffuse in a crystalline metal like Ni and can be absorbed. The formation of metal hydride may modify the entire reaction kinetics of the system. Equivalently, the H-atoms in the bulk can easily go back to the surface and release a large amount of heat. In a plasma process, H-atoms are formed in the plasma, and therefore the energy barrier for dissociative adsorption is dismissed, thus allowing achievement of the threshold coverage without applying a high pressure as in a thermal process. As a result, depending on the crystal plane and type of metal, a large number of H-atoms can be dissolved (absorbed) in the metal catalyst, explaining the high efficiency of plasma-assisted catalytic reactions. Here, the mechanism of H-dissolution is established as a chemical identifier for the investigation of the reaction kinetics of a chemical process.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000406334300034 Publication Date 2017-06-22  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1463-9076 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 4.123 Times cited 10 Open Access OpenAccess  
  Notes Financial support from the Reactive Atmospheric Plasma processIng – eDucation (RAPID) network, through the EU 7th Framework Programme (grant agreement no. 606889), is gratefully acknowledged. The calculations were performed using the Turing HPC infrastructure at the CalcUA core facility of the Universiteit Antwerpen, a division of the Flemish Supercomputer Center VSC, funded by the Hercules Foundation, the Flemish Government department (EWI) and the Universiteit Antwerpen. Approved Most recent IF: 4.123  
  Call Number PLASMANT @ plasmant @ c:irua:144794 Serial 4633  
Permanent link to this record
 

 
Author Dabaghmanesh, S.; Sarmadian, N.; Neyts, E.C.; Partoens, B. url  doi
openurl 
  Title A first principles study of p-type defects in LaCrO3 Type A1 Journal article
  Year 2017 Publication (down) Physical chemistry, chemical physics Abbreviated Journal Phys Chem Chem Phys  
  Volume 19 Issue 34 Pages 22870-22876  
  Keywords A1 Journal article; Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)  
  Abstract Recently, Sr-doped LaCrO3 has been experimentally introduced as a new p-type transparent conducting oxide. It is demonstrated that substituting Sr for La results in inducing p-type conductivity in LaCrO3. Performing first principles calculations we study the electronic structure and formation energy of various point defects in LaCrO3. Our results for the formation energies show that in addition to Sr, two more divalent defects, Ca and Ba, substituting for La in LaCrO3, behave as shallow acceptors in line with previous experimental reports. We further demonstrate that under oxygen-poor growth conditions, these shallow acceptors will be compensated by intrinsic donor-like defects (an oxygen vacancy and Cr on an oxygen site), but in the oxygen-rich growth regime the shallow acceptors have the lowest formation energies between all considered defects and will lead to p-type conductivity.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Cambridge Editor  
  Language Wos 000408671600026 Publication Date 2017-08-01  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1463-9076; 1463-9084 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 4.123 Times cited 16 Open Access OpenAccess  
  Notes ; This work was supported by SIM vzw, Technologiepark 935, BE-9052 Zwijnaarde, Belgium, within the InterPoCo project of the H-INT-S horizontal program. The computational resources and services were provided by the Flemish Supercomputer Center and the HPC infrastructure of the University of Antwerp (CalcUA), both funded by the FWO-Vlaanderen and the Flemish Government. ; Approved Most recent IF: 4.123  
  Call Number UA @ lucian @ c:irua:145621 Serial 4735  
Permanent link to this record
 

 
Author Momot, A.; Amini, M.N.; Reekmans, G.; Lamoen, D.; Partoens, B.; Slocombe, D.R.; Elen, K.; Adriaensens, P.; Hardy, A.; Van Bael, M.K. pdf  url
doi  openurl
  Title A novel explanation for the increased conductivity in annealed Al-doped ZnO: an insight into migration of aluminum and displacement of zinc Type A1 Journal article
  Year 2017 Publication (down) Physical chemistry, chemical physics Abbreviated Journal Phys Chem Chem Phys  
  Volume 19 Issue 40 Pages 27866-27877  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)  
  Abstract A combined experimental and first-principles study is performed to study the origin of conductivity in

ZnO:Al nanoparticles synthesized under controlled conditions via a reflux route using benzylamine as a

solvent. The experimental characterization of the samples by Raman, nuclear magnetic resonance (NMR)

and conductivity measurements indicates that upon annealing in nitrogen, the Al atoms at interstitial

positions migrate to the substitutional positions, creating at the same time Zn interstitials. We provide

evidence for the fact that the formed complex of AlZn and Zni corresponds to the origin of the Knight

shifted peak (KS) we observe in 27Al NMR. As far as we know, the role of this complex has not been

discussed in the literature to date. However, our first-principles calculations show that such a complex is

indeed energetically favoured over the isolated Al interstitial positions. In our calculations we also

address the charge state of the Al interstitials. Further, Zn interstitials can migrate from Al_Zn and possibly

also form Zn clusters, leading to the observed increased conductivity.
 
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000413290500073 Publication Date 2017-10-09  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1463-9076 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 4.123 Times cited 26 Open Access OpenAccess  
  Notes We want to thank the Interuniversity Attraction Poles Programme (P7/05) initiated by the Belgian Science Policy Office (BELSPO) for the financial support. We also acknowledge the Research Foundation Flanders (FWO-Vlaanderen) for support via the MULTIMAR WOG project and under project No. G018914. The computational parts were carried out using the HPC infrastructure at the University of Antwerp (CalcUA), a division of the Flemish Supercomputer Center VSC, supported financially by the Hercules foundation and the Flemish Government (EWI Department). Approved Most recent IF: 4.123  
  Call Number EMAT @ emat @c:irua:146878 Serial 4760  
Permanent link to this record
 

 
Author Sanchez-Barriga, J.; Ogorodnikov, I.I.; Kuznetsov, M.V.; Volykhov, A.A.; Matsui, F.; Callaert, C.; Hadermann, J.; Verbitskiy, N.I.; Koch, R.J.; Varykhalov, A.; Rader, O.; Yashina, L.V. pdf  url
doi  openurl
  Title Observation of hidden atomic order at the interface between Fe and topological insulator Bi2Te3 Type A1 Journal article
  Year 2017 Publication (down) Physical chemistry, chemical physics Abbreviated Journal Phys Chem Chem Phys  
  Volume 19 Issue 45 Pages 30520-30532  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract <script type='text/javascript'>document.write(unpmarked('To realize spintronic devices based on topological insulators (TIs), well-defined interfaces between magnetic metals and TIs are required. Here, we characterize atomically precisely the interface between the 3d transition metal Fe and the TI Bi2Te3 at different stages of its formation. Using photoelectron diffraction and holography, we show that after deposition of up to 3 monolayers Fe on Bi2Te3 at room temperature, the Fe atoms are ordered at the interface despite the surface disorder revealed by our scanning-tunneling microscopy images. We find that Fe occupies two different sites: a hollow adatom deeply relaxed into the Bi2Te3 quintuple layers and an interstitial atom between the third (Te) and fourth (Bi) atomic layers. For both sites, our core-level photoemission spectra and density-functional theory calculations demonstrate simultaneous chemical bonding of Fe to both Te and Bi atoms. We further show that upon deposition of Fe up to a thickness of 20 nm, the Fe atoms penetrate deeper into the bulk forming a 2-5 nm interface layer containing FeTe. In addition, excessive Bi is pushed down into the bulk of Bi2Te3 leading to the formation of septuple layers of Bi3Te4 within a distance of similar to 25 nm from the interface. Controlling the magnetic properties of the complex interface structures revealed by our work will be of critical importance when optimizing the efficiency of spin injection in TI-based devices.'));  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Cambridge Editor  
  Language Wos 000416054400023 Publication Date 2017-10-24  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1463-9076; 1463-9084 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 4.123 Times cited 4 Open Access OpenAccess  
  Notes ; The authors acknowledge financial support within the bilateral program “Russian-German Laboratory at BESSY II” and thank Helmholtz Zentrum Berlin for granting access to the beamlines RGBL, UE112-PGM2a and U49-PGM1. The Supercomputing Center of Lomonosov Moscow State University is gratefully acknowledged for granting access to the “Lomonosov” supercomputer. The work was partially supported by DFG priority program SPP 1666, Impuls- und Vernetzungsfonds der Helmholtz-Gemeinschaft (Grant No. HRJRG-408) and Russian Foundation for Basic Research (Grants No. 13-02-91327 and No. 16-29-06410). C. C. acknowledges support from the University of Antwerp through the BOF grant 31445. The authors thank Dr Vera Neudachina, Daria Tsukanova, Dr Elmar Kataev and Dr Maria Batuk for their support during the XPS and TEM experiments. ; Approved Most recent IF: 4.123  
  Call Number UA @ lucian @ c:irua:147659 Serial 4888  
Permanent link to this record
 

 
Author Loreto, S.; Cuypers, B.; Brokken, J.; Van Doorslaer, S.; De Wael, K.; Meynen, V. pdf  url
doi  openurl
  Title The effect of the buffer solution on the adsorption and stability of horse heart myoglobin on commercial mesoporous titanium dioxide : a matter of the right choice Type A1 Journal article
  Year 2017 Publication (down) Physical chemistry, chemical physics Abbreviated Journal Phys Chem Chem Phys  
  Volume 19 Issue 21 Pages 13503-13514  
  Keywords A1 Journal article; Laboratory of adsorption and catalysis (LADCA); AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)  
  Abstract Despite the numerous studies on the adsorption of different proteins onto mesoporous titanium dioxide and indications on the important role of buffer solutions in bioactivity, a systematic study on the impact of the buffer on the protein incorporation into porous substrates is still lacking. We here studied the interaction between a commercial mesoporous TiO2 and three of the most used buffers for protein incorporation, i.e. HEPES, Tris and phosphate buffer. In addition, this paper analyzes the adsorption of horse heart myoglobin (hhMb) onto commercial mesoporous TiO2 as a model system to test the influence of buffers on the protein incorporation behavior in mesoporous TiO2. N2 sorption analysis, FT-IR and TGA/DTG measurements were used to evaluate the interaction between the buffers and the TiO2 surface, and the effect of such an interaction on hhMb adsorption. Cyclic voltammetry (CV) and electron paramagnetic resonance (EPR) were used to detect changes in the microenvironment surrounding the heme. The three buffers show a completely different interaction with the TiO2 surface, which drastically affects the adsorption of myoglobin as well as its structure and electrochemical activity. Therefore, special attention is required while choosing the buffer medium to avoid misguided evaluation of protein adsorption on mesoporous TiO2.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000402488300013 Publication Date 2017-04-27  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1463-9076; 1463-9084 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 4.123 Times cited 2 Open Access  
  Notes ; We are grateful to Gert Nuyts for performing the XRF measurements, and Dr Stanislav Trashin for his assistance during the electrochemical experiments. This work is supported by the Research Foundation – Flanders (FWO) (grant G.0687.13) and the University of Antwerp (BOF project). ; Approved Most recent IF: 4.123  
  Call Number UA @ admin @ c:irua:143514 Serial 5582  
Permanent link to this record
 

 
Author Fernández Becerra, V.; Milošević, M.V. pdf  doi
openurl 
  Title Dynamics of skyrmions and edge states in the resistive regime of mesoscopic p-wave superconductors Type A1 Journal article
  Year 2017 Publication (down) Physica: C : superconductivity Abbreviated Journal Physica C  
  Volume 533 Issue 533 Pages 91-95  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract In a mesoscopic sample of a chiral p-wave superconductor, novel states comprising skyrmions and edge states have been stabilized in out-of-plane applied magnetic field. Using the time-dependent Ginzburg-Landau equations we shed light on the dynamic response of such states to an external applied current. Three different regimes are obtained, namely, the superconducting (stationary), resistive (non-stationary) and normal regime, similarly to conventional s-wave superconductors. However, in the resistive regime and depending on the external current, we found that moving skyrmions and the edge state behave distinctly different from the conventional kinematic vortex, thereby providing new fingerprints for identification of p-wave superconductivity. (C) 2016 Elsevier B.V. All rights reserved.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Amsterdam Editor  
  Language Wos 000395954100014 Publication Date 2016-07-07  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0921-4534 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 1.404 Times cited 3 Open Access  
  Notes Approved Most recent IF: 1.404  
  Call Number UA @ lucian @ c:irua:142534 Serial 4592  
Permanent link to this record
 

 
Author Magnus, W.; Lemmens, L.; Brosens, F. pdf  doi
openurl 
  Title Quantum canonical ensemble : a projection operator approach Type A1 Journal article
  Year 2017 Publication (down) Physica: A : theoretical and statistical physics Abbreviated Journal Physica A  
  Volume 482 Issue Pages 1-13  
  Keywords A1 Journal article; Theory of quantum systems and complex systems; Condensed Matter Theory (CMT)  
  Abstract Knowing the exact number of particles N, and taking this knowledge into account, the quantum canonical ensemble imposes a constraint on the occupation number operators. The constraint particularly hampers the systematic calculation of the partition function and any relevant thermodynamic expectation value for arbitrary but fixed N. On the other hand, fixing only the average number of particles, one may remove the above constraint and simply factorize the traces in Fock space into traces over single-particle states. As is well known, that would be the strategy of the grand-canonical ensemble which, however, comes with an additional Lagrange multiplier to impose the average number of particles. The appearance of this multiplier can be avoided by invoking a projection operator that enables a constraint-free computation of the partition function and its derived quantities in the canonical ensemble, at the price of an angular or contour integration. Introduced in the recent past to handle various issues related to particle-number projected statistics, the projection operator approach proves beneficial to a wide variety of problems in condensed matter physics for which the canonical ensemble offers a natural and appropriate environment. In this light, we present a systematic treatment of the canonical ensemble that embeds the projection operator into the formalism of second quantization while explicitly fixing N, the very number of particles rather than the average. Being applicable to both bosonic and fermionic systems in arbitrary dimensions, transparent integral representations are provided for the partition function Z(N) and the Helmholtz free energy F-N as well as for two- and four-point correlation functions. The chemical potential is not a Lagrange multiplier regulating the average particle number but can be extracted from FN+1 – F-N, as illustrated for a two-dimensional fermion gas. (C) 2017 Elsevier B.V. All rights reserved.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Amsterdam Editor  
  Language Wos 000405885500001 Publication Date 2017-04-20  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0378-4371 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.243 Times cited 1 Open Access  
  Notes ; ; Approved Most recent IF: 2.243  
  Call Number UA @ lucian @ c:irua:145145 Serial 4722  
Permanent link to this record
 

 
Author Vanherck, J.; Schulenborg, J.; Saptsov, R.B.; Splettstoesser, J.; Wegewijs, M.R. pdf  url
doi  openurl
  Title Relaxation of quantum dots in a magnetic field at finite bias -Charge, spin, and heat currents Type A1 Journal article
  Year 2017 Publication (down) Physica status solidi: B: basic research Abbreviated Journal Phys Status Solidi B  
  Volume 254 Issue 3 Pages Unsp 1600614  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract <script type='text/javascript'>document.write(unpmarked('We perform a detailed study of the effect of finite bias and magnetic field on the tunneling-induced decay of the state of a quantum dot by applying a recently discovered general duality [Phys. Rev. B 93, 81411 (2016)]. This duality provides deep physical insight into the decay dynamics of electronic open quantum systems with strong Coulomb interaction. It associates the amplitudes of decay eigenmodes of the actual system to the eigenmodes of a so-called dual system with attractive interaction. Thereby, it predicts many surprising features in the transient transport and its dependence on experimental control parameters: the attractive interaction of the dual model shows up as sharp features in the amplitudes of measurable time-dependent currents through the actual repulsive system. In particular, for interacting quantum dots, the time-dependent heat current exhibits a decay mode that dissipates the interaction energy and that is tied to the fermion parity of the system. We show that its decay amplitude has an unexpected gate-voltage dependence that is robust up to sizable bias voltages and then bifurcates, reflecting that the Coulomb blockade is lifted in the dual system. Furthermore, combining our duality relation with the known Iche-duality, we derive new symmetry properties of the decay rates as a function of magnetic field and gate voltage. Finally, we quantify charge- and spin-mode mixing due to the magnetic field using a single mixing parameter.'));  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Berlin Editor  
  Language Wos 000395441500011 Publication Date 2017-01-18  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0370-1972 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 1.674 Times cited 4 Open Access  
  Notes ; We acknowledge the financial support of Erasmus Mundus (J. V.), DFG project SCHO 641/7-1 (R.B.S. and M.R.W), the Swedish VR (J.Sc., J.Sp.), and the Knut and Alice Wallenberg Foundation (J. Sp.). The authors thank F. Haupt and N. Dittmann for useful discussions on the topic. ; Approved Most recent IF: 1.674  
  Call Number UA @ lucian @ c:irua:142510 Serial 4894  
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Author de de Meux, A.J.; Bhoolokam, A.; Pourtois, G.; Genoe, J.; Heremans, P. pdf  doi
openurl 
  Title Oxygen vacancies effects in a-IGZO : formation mechanisms, hysteresis, and negative bias stress effects Type A1 Journal article
  Year 2017 Publication (down) Physica status solidi : A : applications and materials science Abbreviated Journal Phys Status Solidi A  
  Volume 214 Issue 6 Pages 1600889  
  Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)  
  Abstract The amorphous oxide semiconductor Indium-Gallium-Zinc-Oxide (a-IGZO) has gained a large technological relevance as a semiconductor for thin-film transistors in active-matrix displays. Yet, major questions remain unanswered regarding the atomic origin of threshold voltage control, doping level, hysteresis, negative bias stress (NBS), and negative bias illumination stress (NBIS). We undertake a systematic study of the effects of oxygen vacancies on the properties of a-IGZO by relating experimental observations to microscopic insights gained from first-principle simulations. It is found that the amorphous nature of the semiconductor allows unusually large atomic relaxations. In some cases, oxygen vacancies are found to behave as perfect shallow donors without the formation of structural defects. Once structural defects are formed, their transition states can vary upon charge and discharge cycles. We associate this phenomenon to a possible presence of hysteresis in the transfer curve of the devices. Under NBS, the creation of oxygen vacancies becomes energetically very stable, hence thermodynamically very likely. This generation process is correlated with the occurrence of the negative bias stress instabilities observed in a-IGZO transistors. While oxygen vacancies can therefore be related to NBS and hysteresis, it appears unlikely from our results that they are direct causes of NBIS, contrary to common belief.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000403339900012 Publication Date 2017-03-02  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1862-6300 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 1.775 Times cited 8 Open Access Not_Open_Access  
  Notes Approved Most recent IF: 1.775  
  Call Number UA @ lucian @ c:irua:144219 Serial 4678  
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Author Sentosun, K.; Lobato, I.; Bladt, E.; Zhang, Y.; Palenstijn, W.J.; Batenburg, K.J.; Van Dyck, D.; Bals, S. pdf  url
doi  openurl
  Title Artifact Reduction Based on Sinogram Interpolation for the 3D Reconstruction of Nanoparticles Using Electron Tomography Type A1 Journal article
  Year 2017 Publication (down) Particle and particle systems characterization Abbreviated Journal Part. Part. Syst. Charact.  
  Volume 34 Issue 34 Pages 1700287  
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Vision lab  
  Abstract Electron tomography is a well-known technique providing a 3D characterization of the morphology and chemical composition of nanoparticles. However, several reasons hamper the acquisition of tilt series with a large number of projection images, which deteriorate the quality of the 3D reconstruction. Here, an inpainting method that is based on sinogram interpolation is proposed, which enables one to reduce artifacts in the reconstruction related to a limited tilt series of projection images. The advantages of the approach will be demonstrated for the 3D characterization of nanoparticles using phantoms and several case studies.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000418416100005 Publication Date 2017-10-27  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1521-4117 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor Times cited 2 Open Access OpenAccess  
  Notes K.S. and S.B. acknowledge support from the Fund for Scientific ResearchFlanders (FWO) (G019014N and G021814N). S.B. acknowledges financial support from European Research Council (ERC Starting Grant #335078-COLOURATOM). Y.Z. acknowledges financial support from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie Grant Agreement No. 665501 through a FWO [PEGASUS]2 Marie Skłodowska-Curie fellowship (12U4917N). The authors would like to thank Prof. Luis Liz-Marzán for provision of the samples. (ROMEO:yellow; preprint:; postprint:restricted ; pdfversion:cannot); saraecas; ECAS_Sara; Approved Most recent IF: NA  
  Call Number EMAT @ emat @c:irua:147857UA @ admin @ c:irua:147857 Serial 4798  
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Author Ata, I.; Ben Dkhil, S.; Pfannmoeller, M.; Bals, S.; Duche, D.; Simon, J.-J.; Koganezawa, T.; Yoshimoto, N.; Videlot-Ackermann, C.; Margeat, O.; Ackermann, J.; Baeuerle, P. url  doi
openurl 
  Title The influence of branched alkyl side chains in A-D-A oligothiophenes on the photovoltaic performance and morphology of solution-processed bulk-heterojunction solar cells Type A1 Journal article
  Year 2017 Publication (down) Organic chemistry frontiers : an international journal of organic chemistry Abbreviated Journal Org Chem Front  
  Volume 4 Issue 4 Pages 1561-1573  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Besides providing sufficient solubility, branched alkyl chains also affect the film-forming and packing properties of organic semiconductors. In order to avoid steric hindrance as it is present in wide-spread alkyl chains comprising a branching point position at the C2-position, i.e., 2-ethylhexyl, the branching point can be moved away from the pi-conjugated backbone. In this report, we study the influence of the modification of the branching point position from the C2-position in 2-hexyldecylamine (1) to the C4-position in 4-hexyldecylamine (2) connected to the central dithieno[3,2-b: 2', 3'-d] pyrrole (DTP) moiety in a well-studied A-D-A oligothiophene on the optoelectronic properties and photovoltaic performance in solution- processed bulk heterojunction solar cells (BHJSCs) with [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) as the acceptor material. Post-treatment of the photoactive layers is performed via solvent vapor annealing (SVA) in order to improve the film microstructure of the bulk heterojunction. The time evolution of nanoscale morphological changes is followed by combining scanning transmission electron microscopy with low-energy-loss spectroscopic imaging (STEM-SI), solid-state absorption spectroscopy, and two-dimensional grazing incidence X-ray diffraction (2D-GIXRD). Our results show an improvement of the photovoltaic performance that is dependent on the branching point position in the donor oligomer. Optical spacers are utilized to increase light absorption inside the co-oligomer 2-based BHJSCs leading to increased power conversion efficiencies (PCEs) of 8.2% when compared to the corresponding co-oligomer 1-based devices. A STEM-SI analysis of the respective device cross-sections of active layers containing 1 and 2 as donor materials indeed reveals significant differences in their respective active layer morphologies.  
  Address  
  Corporate Author Thesis  
  Publisher RSC Publishing Place of Publication London Editor  
  Language Wos 000406374800013 Publication Date 2017-05-02  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2052-4129 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 4.955 Times cited 24 Open Access OpenAccess  
  Notes ; We acknowledge financial support by the European Commission under the project “SUNFLOWER” (FP7-ICT-2011-7, grant number: 287594) and S.B. acknowledges the ERC Starting Grant Colouratoms (335078). ; Approved Most recent IF: 4.955  
  Call Number UA @ lucian @ c:irua:145176UA @ admin @ c:irua:145176 Serial 4727  
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