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Author Bacaksiz, C.; Sahin, H.; Ozaydin, H.D.; Horzum, S.; Senger, R.T.; Peeters, F.M.
  Title Hexagonal A1N : dimensional-crossover-driven band-gap transition Type A1 Journal article
  Year 2015 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
  Volume 91 Issue (down) 91 Pages 085430
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Motivated by a recent experiment that reported the successful synthesis of hexagonal (h) AlN [Tsipas et al., Appl. Phys. Lett. 103, 251605 (2013)], we investigate structural, electronic, and vibrational properties of bulk, bilayer, and monolayer structures of h-AlN by using first-principles calculations. We show that the hexagonal phase of the bulk h-AlN is a stable direct-band-gap semiconductor. The calculated phonon spectrum displays a rigid-layer shear mode at 274 cm(-1) and an E-g mode at 703 cm(-1), which are observable by Raman measurements. In addition, single-layer h-AlN is an indirect-band-gap semiconductor with a nonmagnetic ground state. For the bilayer structure, AA'-type stacking is found to be the most favorable one, and interlayer interaction is strong. While N-layered h-AlN is an indirect-band-gap semiconductor for N = 1 – 9, we predict that thicker structures (N >= 10) have a direct band gap at the Gamma point. The number-of-layer-dependent band-gap transitions in h-AlN is interesting in that it is significantly different from the indirect-to-direct crossover obtained in the transition-metal dichalcogenides.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000350319200020 Publication Date 2015-02-27
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 3.836 Times cited 99 Open Access
  Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Methusalem foundation of the Flemish government. Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure). C.B. and R.T.S. acknowledge the support from TUBITAK Project No 114F397. H.S. is supported by a FWO Pegasus Long Marie Curie Fellowship. ; Approved Most recent IF: 3.836; 2015 IF: 3.736
  Call Number c:irua:125416 Serial 1421
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Author Van Boxem, R.; Partoens, B.; Verbeeck, J.
  Title Inelastic electron-vortex-beam scattering Type A1 Journal article
  Year 2015 Publication Physical review : A : atomic, molecular and optical physics Abbreviated Journal Phys Rev A
  Volume 91 Issue (down) 91 Pages 032703
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
  Abstract Recent theoretical and experimental developments in the field of electron-vortex-beam physics have raised questions about what exactly this novelty in the field of electron microscopy (and other fields, such as particle physics) really provides. An important part of the answer to these questions lies in scattering theory. The present investigation explores various aspects of inelastic quantum scattering theory for cylindrically symmetric beams with orbital angular momentum. The model system of Coulomb scattering on a hydrogen atom provides the setting to address various open questions: How is momentum transferred? Do vortex beams selectively excite atoms, and how can one employ vortex beams to detect magnetic transitions? The analytical approach presented here provides answers to these questions. OAM transfer is possible, but not through selective excitation; rather, by pre- and postselection one can filter out the relevant contributions to a specific signal.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Lancaster, Pa Editor
  Language Wos 000351035000004 Publication Date 2015-03-16
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1050-2947;1094-1622; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 2.925 Times cited 31 Open Access
  Notes Fwo; 312483 Esteem2; 278510 Vortex; esteem2jra3 ECASJO; Approved Most recent IF: 2.925; 2015 IF: 2.808
  Call Number c:irua:123925 c:irua:123925UA @ admin @ c:irua:123925 Serial 1607
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Author Nishio, K.; Lu, A.K.A.; Pourtois, G.
  Title Low-strain Si/O superlattices with tunable electronic properties : ab initio calculations Type A1 Journal article
  Year 2015 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
  Volume 91 Issue (down) 91 Pages 165303
  Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
  Abstract We propose that low-strain Si/O superlattices can be constructed by connecting reconstructed Si{001} surfaces by Si-O-Si bridges. Ab initio calculations show that our models are energetically more favorable than all the models proposed so far. The part of our Si/O superlattice model is experimentally accessible just by oxidizing a Si( 001) substrate. To complete our Si/O superlattice model, we propose a three-step method. We also explore the potential of our Si/O superlattice models for new materials used in future Si electronics. We find that the location of the channel where the carriers travel can be controlled between the interfaces and the Si layers by the insertion of O atoms into the Si-Si dimers. By revealing the origins of the interface electron and hole states, we find that similar interface states should be easily achieved for Si slabs and Si substrates. Interestingly, the interface electrons and holes have small effective masses in the direction parallel to the channel and large effective masses in the direction normal to the channel, which makes the Si/O superlattices attractive to be used for channel materials. We also find that the valley splitting of Si is enhanced by the formation of the Si/O/Si interfaces, which is ideal for developing Si-based qubits. Our findings open new perspectives to design and control the electronic properties of Si.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000352986700002 Publication Date 2015-04-16
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 3.836 Times cited 6 Open Access
  Notes Approved Most recent IF: 3.836; 2015 IF: 3.736
  Call Number c:irua:125998 Serial 1852
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Author Zha, G.-Q.; Covaci, L.; Peeters, F.M.; Zhou, S.-P.
  Title Mixed pairing symmetries and flux-induced spin current in mesoscopic superconducting loops with spin correlations Type A1 Journal article
  Year 2015 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
  Volume 91 Issue (down) 91 Pages 214504
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract We numerically investigate the mixed pairing symmetries inmesoscopic superconducting loops in the presence of spin correlations by solving the Bogoliubov-de Gennes equations self-consistently. The spatial variations of the superconducting order parameters and the spontaneous magnetization are determined by the band structure. When the threaded magnetic flux turns on, the charge and spin currents both emerge and depict periodic evolution. In the case of a mesoscopic loop with dominant triplet p(x) +/- ip(y)-wave symmetry, a slight change of the chemical potential may lead to novel flux-dependent evolution patterns of the ground-state energy and the magnetization. The spin-polarized currents show pronounced quantum oscillations with fractional periods due to the appearance of energy jumps in flux, accompanied with a steplike feature of the enhanced spin current. Particularly, at some appropriate flux, the peaks of the zero-energy local density of states clearly indicate the occurrence of the odd-frequency pairing. In the case of a superconducting loop with dominant singlet d(x2-y2)-wave symmetry, the spatial profiles of the zero-energy local density of states and the magnetization show spin-dependent features on different sample diagonals. Moreover, the evolution of the flux-induced spin current always exhibits an hc/e periodicity.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000355647100003 Publication Date 2015-06-05
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 3.836 Times cited 15 Open Access
  Notes ; This work was supported by the National Natural Science Foundation of China under Grants No. 61371020 and No. 61271163, by the Visiting Scholar Program of Shanghai Municipal Education Commission, and by the Flemish Science Foundation (FWO-Vl). ; Approved Most recent IF: 3.836; 2015 IF: 3.736
  Call Number c:irua:126433 Serial 2089
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Author Muñoz, W.A.; Covaci, L.; Peeters, F.M.
  Title Disordered graphene Josephson junctions Type A1 Journal article
  Year 2015 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
  Volume 91 Issue (down) 91 Pages 054506
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract A tight-binding approach based on the Chebyshev-Bogoliubov-de Gennes method is used to describe disordered single-layer graphene Josephson junctions. Scattering by vacancies, ripples, or charged impurities is included. We compute the Josephson current and investigate the nature of multiple Andreev reflections, which induce bound states appearing as peaks in the density of states for energies below the superconducting gap. In the presence of single-atom vacancies, we observe a strong suppression of the supercurrent, which is a consequence of strong intervalley scattering. Although lattice deformations should not induce intervalley scattering, we find that the supercurrent is still suppressed, which is due to the presence of pseudomagnetic barriers. For charged impurities, we consider two cases depending on whether the average doping is zero, i.e., existence of electron-hole puddles, or finite. In both cases, short-range impurities strongly affect the supercurrent, similar to the vacancies scenario.
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  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000349436500001 Publication Date 2015-02-06
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 3.836 Times cited 7 Open Access
  Notes This work was supported by the Flemish Science Foundation (FWO-Vlaanderen) and the Methusalem funding of the Flemish Government. Approved Most recent IF: 3.836; 2015 IF: 3.736
  Call Number c:irua:129192 Serial 3961
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Author Szaszko-Bogar, V.; Peeters, F.M.; Foeldi, P.
  Title Oscillating spin-orbit interaction in two-dimensional superlattices : sharp transmission resonances and time-dependent spin-polarized currents Type A1 Journal article
  Year 2015 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
  Volume 91 Issue (down) 91 Pages 235311
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract We consider ballistic transport through a lateral, two-dimensional superlattice with experimentally realizable, sinusoidally oscillating, Rashba-type spin-orbit interaction (SOI). The periodic structure of the rectangular lattice produces a spin-dependent miniband structure for static SOI. Using Floquet theory, transmission peaks are shown to appear in themini-bandgaps as a consequence of the additional, time-dependent SOI. A detailed analysis shows that this effect is due to the generation of harmonics of the driving frequency, via which, e.g., resonances that cannot be excited in the case of static SOI become available. Additionally, the transmitted current shows space-and time-dependent partial spin polarization, in other words, polarization waves propagate through the superlattice.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000355956500003 Publication Date 2015-06-10
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 3.836 Times cited 10 Open Access
  Notes ; This work was partially supported by the European Union and the European Social Fund through Projects No. TAMOP-4.2.2.C-11/1/KONV-2012-0010 and No. TAMOP-4.2.2.A-11/1/KONV-2012-0060, and by the Hungarian Scientific Research Fund (OTKA) under Contracts No. T81364 and No. 116688. The ELI-ALPS Project (GOP-1.1.1-12/B-2012-0001) is supported by the European Union and cofinanced by the European Regional Development Fund. ; Approved Most recent IF: 3.836; 2015 IF: 3.736
  Call Number c:irua:126432 Serial 2534
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Author Aierken, Y.; Sahin, H.; Iyikanat, F.; Horzum, S.; Suslu, A.; Chen, B.; Senger, R.T.; Tongay, S.; Peeters, F.M.
  Title Portlandite crystal : bulk, bilayer, and monolayer structures Type A1 Journal article
  Year 2015 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
  Volume 91 Issue (down) 91 Pages 245413
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Ca(OH)(2) crystals, well known as portlandite, are grown in layered form, and we found that they can be exfoliated on different substrates. We performed first principles calculations to investigate the structural, electronic, vibrational, and mechanical properties of bulk, bilayer, and monolayer structures of this material. Different from other lamellar structures such as graphite and transition-metal dichalcogenides, intralayer bonding in Ca(OH)(2) is mainly ionic, while the interlayer interaction remains a weak dispersion-type force. Unlike well-known transition-metal dichalcogenides that exhibit an indirect-to-direct band gap crossover when going from bulk to a single layer, Ca(OH)(2) is a direct band gap semiconductor independent of the number layers. The in-plane Young's modulus and the in-plane shear modulus of monolayer Ca(OH)(2) are predicted to be quite low while the in-plane Poisson ratio is larger in comparison to those in the monolayer of ionic crystal BN. We measured the Raman spectrum of bulk Ca(OH)(2) and identified the high-frequency OH stretching mode A(1g) at 3620 cm(-1). In this study, bilayer and monolayer portlandite [Ca(OH)(2)] are predicted to be stable and their characteristics are analyzed in detail. Our results can guide further research on ultrathin hydroxites.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000356135600007 Publication Date 2015-06-12
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 3.836 Times cited 29 Open Access
  Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Methusalem foundation of the Flemish government. Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure). H.S. is supported by a FWO Pegasus Long Marie Curie Fellowship. ; Approved Most recent IF: 3.836; 2015 IF: 3.736
  Call Number c:irua:126983 Serial 2675
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Author Zalipaev, V.; Linton, C.M.; Croitoru, M.D.; Vagov, A.
  Title Resonant tunneling and localized states in a graphene monolayer with a mass gap Type A1 Journal article
  Year 2015 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
  Volume 91 Issue (down) 91 Pages 085405
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract We study tunneling of quasiparticles through potential barriers in a graphene monolayer with the mass gap using a semiclassical (WKB) approach. The main equations are derived in away similar to the WKB theory for the Schrodinger equation, which allows for explicit solutions at all orders. The analog of the classical action is used to distinguish types of possible stationary states in the system. The analysis focuses on the resonant scattering and the hole states localized in the vicinity of a barrier that are often overlooked. The scattering coefficients for the physically interesting limits are obtained by matching the WKB approximation with the known solutions at turning points. The localized states demonstrate unconventional properties and lead to alterations of the single particle density of states.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000351773900004 Publication Date 2015-02-05
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 3.836 Times cited 3 Open Access
  Notes ; M.D.C. acknowledges the Belgian Science Policy (BELSPO Back to Belgium Grant). ; Approved Most recent IF: 3.836; 2015 IF: 3.736
  Call Number c:irua:125523 Serial 2891
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Author Singh, S.K.; Neek-Amal, M.; Costamagna, S.; Peeters, F.M.
  Title Rippling, buckling, and melting of single- and multilayer MoS2 Type A1 Journal article
  Year 2015 Publication Physical Review B Abbreviated Journal Phys Rev B
  Volume 91 Issue (down) 91 Pages 014101
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Large-scale atomistic simulations using the reactive empirical bond order force field approach is implemented to investigate thermal and mechanical properties of single-layer (SL) and multilayer (ML) molybdenum disulfide (MoS2). The amplitude of the intrinsic ripples of SL MoS2 are found to be smaller than those exhibited by graphene (GE). Furthermore, because of the van der Waals interaction between layers, the out-of-plane thermal fluctuations of ML MoS2 decreases rapidly with increasing number of layers. This trend is confirmed by the buckling transition due to uniaxial stress which occurs for a significantly larger applied tension as compared to graphene. For SL MoS2, the melting temperature is estimated to be 3700 K which occurs through dimerization followed by the formation of small molecules consisting of two to five atoms. When different types of vacancies are inserted in the SL MoS2 it results in a decrease of both the melting temperature as well as the stiffness.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Lancaster, Pa Editor
  Language Wos 000347921300001 Publication Date 2015-01-05
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 3.836 Times cited 40 Open Access
  Notes ; This work is supported by the ESF-Eurographene project CONGRAN, the Flemish Science Foundation (FWO-VI), and the Methusalem Foundation of the Flemish Government. We acknowledge funding from the FWO (Belgium)-MINCyT (Argentina) collaborative research project. We would like to thanks Prof. Douglas E. Spearot [26] for giving us the implemented parameters of Mo-S in LAMMPS. ; Approved Most recent IF: 3.836; 2015 IF: 3.736
  Call Number c:irua:123834 Serial 2909
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Author Leenaerts, O.; Schoeters, B.; Partoens, B.
  Title Stable kagome lattices from group IV elements Type A1 Journal article
  Year 2015 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
  Volume 91 Issue (down) 91 Pages 115202
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract A thorough investigation of three-dimensional kagome lattices of group IV elements is performed with first-principles calculations. The investigated kagome lattices of silicon and germanium are found to be of similar stability as the recently proposed carbon kagome lattice. Carbon and silicon kagome lattices are both direct-gap semiconductors but they have qualitatively different electronic band structures. While direct optical transitions between the valence and conduction bands are allowed in the carbon case, no such transitions can be observed for silicon. The kagome lattice of germanium exhibits semimetallic behavior but can be transformed into a semiconductor after compression.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000351900700003 Publication Date 2015-03-10
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 3.836 Times cited 12 Open Access
  Notes ; This work was supported by the Fonds Wetenschappelijk Onderzoek (FWO-Vl). The computational resources and services used in this work were provided by the VSC (Flemish Supercomputer Center), funded by the Hercules Foundation and the Flemish Government – department EWI. ; Approved Most recent IF: 3.836; 2015 IF: 3.736
  Call Number c:irua:125516 Serial 3144
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Author Zhang, L.-F.; Covaci, L.; Peeters, F.M.
  Title Tomasch effect in nanoscale superconductors Type A1 Journal article
  Year 2015 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
  Volume 91 Issue (down) 91 Pages 024508
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract The Tomasch effect (TE) is due to quasiparticle interference (QPI) as induced by a nonuniform superconducting order parameter, which results in oscillations in the density of states (DOS) at energies above the superconducting gap. Quantum confinement in nanoscale superconductors leads to an inhomogenerous distribution of the Cooperpair condensate, which, as we found, triggers the manifestation of a new TE. We investigate the electronic structure of nanoscale superconductors by solving the Bogoliubov-de Gennes (BdG) equations self-consistently and describe the TE determined by two types of processes, involving two-or three-subband QPIs. Both types of QPIs result in additional BCS-like Bogoliubov-quasiparticles and BCS-like energy gaps leading to oscillations in the DOS and modulated wave patterns in the local density of states. These effects are strongly related to the symmetries of the system. A reduced 4 x 4 inter-subband BdG Hamiltonian is established in order to describe analytically the TE of two-subband QPIs. Our study is relevant to nanoscale superconductors, either nanowires or thin films, Bose-Einsten condensates, and confined systems such as two-dimensional electron gas interface superconductivity.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Lancaster, Pa Editor
  Language Wos 000348473700003 Publication Date 2015-01-16
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 3.836 Times cited 6 Open Access
  Notes ; This work was supported by the Flemish Science Foundation (FWO-Vlaanderen) and the Methusalem funding of the Flemish Government. ; Approved Most recent IF: 3.836; 2015 IF: 3.736
  Call Number c:irua:123864 Serial 3670
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Author Juchtmans, R.; Béché, A.; Abakumov, A.; Batuk, M.; Verbeeck, J.
  Title Using electron vortex beams to determine chirality of crystals in transmission electron microscopy Type A1 Journal article
  Year 2015 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
  Volume 91 Issue (down) 91 Pages 094112
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract We investigate electron vortex beams elastically scattered on chiral crystals. After deriving a general expression for the scattering amplitude of a vortex electron, we study its diffraction on point scatterers arranged on a helix. We derive a relation between the handedness of the helix and the topological charge of the electron vortex on one hand and the symmetry of the higher-order Laue zones in the diffraction pattern on the other for kinematically and dynamically scattered electrons. We then extend this to atoms arranged on a helix as found in crystals which belong to chiral space groups and propose a method to determine the handedness of such crystals by looking at the symmetry of the diffraction pattern. In contrast to alternative methods, our technique does not require multiple scattering, which makes it possible to also investigate extremely thin samples in which multiple scattering is suppressed. In order to verify the model, elastic scattering simulations are performed, and an experimental demonstration on Mn2Sb2O7 is given in which we find the sample to belong to the right-handed variant of its enantiomorphic pair. This demonstrates the usefulness of electron vortex beams to reveal the chirality of crystals in a transmission electron microscope and provides the required theoretical basis for further developments in this field.
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  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000352017000002 Publication Date 2015-03-27
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 3.836 Times cited 54 Open Access
  Notes Fwo; 312483 Esteem2; 278510 Vortex; esteem2jra1; esteem2jra2 ECASJO_; Approved Most recent IF: 3.836; 2015 IF: 3.736
  Call Number c:irua:125512 c:irua:125512 Serial 3825
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Author Richardson, C.L.; Edkins, S.D.; Berdiyorov, G.R.; Chua, C.J.; Griffiths, J.P.; Jones, G.A.C.; Buitelaar, M.R.; Narayan, V.; Sfigakis, F.; Smith, C.G.; Covaci, L.; Connolly, M.R.;
  Title Vortex detection and quantum transport in mesoscopic graphene Josephson-junction arrays Type A1 Journal article
  Year 2015 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
  Volume 91 Issue (down) 91 Pages 245418
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract We investigate mesoscopic Josephson-junction arrays created by patterning superconducting disks on monolayer graphene, concentrating on the high-T/T-c regime of these devices and the phenomena which contribute to the superconducting glass state in diffusive arrays. We observe features in the magnetoconductance at rational fractions of flux quanta per array unit cell, which we attribute to the formation of flux-quantized vortices. The applied fields at which the features occur are well described by Ginzburg-Landau simulations that take into account the number of unit cells in the array. We find that the mean conductance and universal conductance fluctuations are both enhanced below the critical temperature and field of the superconductor, with greater enhancement away from the graphene Dirac point.
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  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000356129800012 Publication Date 2015-06-15
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 3.836 Times cited 2 Open Access
  Notes ; This work was financially supported by the Engineering and Physical Sciences Research Council, and an NPL/EPSRC Joint Postdoctoral Partnership. Supporting data for this paper is available at the DSpace@Cambridge data repository (https://www.repository.cam.ac.uk/handle/1810/248242). ; Approved Most recent IF: 3.836; 2015 IF: 3.736
  Call Number c:irua:126982 Serial 3865
Permanent link to this record
 

 
Author Chaves, A.; Low, T.; Avouris, P.; Çakir, D.; Peeters, F.M.
  Title Anisotropic exciton Stark shift in black phosphorus Type A1 Journal article
  Year 2015 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
  Volume 91 Issue (down) 91 Pages 155311
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract We calculate the excitonic spectrum of few-layer black phosphorus by direct diagonalization of the effective mass Hamiltonian in the presence of an applied in-plane electric field. The strong attractive interaction between electrons and holes in this system allows one to investigate the Stark effect up to very high ionizing fields, including also the excited states. Our results show that the band anisotropy in black phosphorus becomes evident in the direction-dependent field-induced polarizability of the exciton.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Lancaster, Pa Editor
  Language Wos 000353459200005 Publication Date 2015-04-27
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1098-0121; 1550-235x ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 3.836 Times cited 88 Open Access
  Notes ; Discussions with J. M. Pereira Jr. and J. S. de Souza are gratefully acknowledged. This work was supported by the Brazilian Council for Research (CNPq) through the PQ and Science Without Borders programs, the Flemish Science Foundation (FWO-Vl), the Methusalem programme of the Flemish government, and the Bilateral program (CNPq-FWO) between Flanders and Brazil. ; Approved Most recent IF: 3.836; 2015 IF: 3.736
  Call Number UA @ lucian @ c:irua:132506 Serial 4141
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Author Sadeghi, A.; Neek-Amal, M.; Berdiyorov, G.R.; Peeters, F.M.
  Title Diffusion of fluorine on and between graphene layers Type A1 Journal article
  Year 2015 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
  Volume 91 Issue (down) 91 Pages 014304
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Using first-principles calculations and reactive force field molecular dynamics simulations, we study the structural properties and dynamics of a fluorine (F) atom, either adsorbed on the surface of single layer graphene (F/GE) or between the layers of AB stacked bilayer graphene (F@ bilayer graphene). It is found that the diffusion of the F atom is very different in those cases, and that the mobility of the F atom increases by about an order of magnitude when inserted between two graphene layers. The obtained diffusion constant for F/GE is twice larger than that experimentally found for gold adatom and theoretically found for C-60 molecule on graphene. Our study provides important physical insights into the dynamics of fluorine atoms between and on graphene layers and explains the mechanism behind the separation of graphite layers due to intercalation of F atoms.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Lancaster, Pa Editor
  Language Wos 000349125800002 Publication Date 2015-01-08
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1098-0121; 1550-235x ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 3.836 Times cited 15 Open Access
  Notes ; This work was supported by the Flemish Science Foundation (FWO-VI) and the Methusalem Foundation of the Flemish Government. ; Approved Most recent IF: 3.836; 2015 IF: 3.736
  Call Number UA @ lucian @ c:irua:132561 Serial 4161
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Author Pavlović, S.; Peeters, F.M.
  Title Electronic properties of triangular and hexagonal MoS2 quantum dots Type A1 Journal article
  Year 2015 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
  Volume 91 Issue (down) 91 Pages 155410
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Using the tight-binding approach, we calculate the electronic structure of triangular and hexagonal MoS2 quantum dots. Due to the orbital asymmetry we show that it is possible to form quantum dots with the same shape but having different electronic properties. The electronic states of triangular and hexagonal quantum dots are explored, as well as the local and total density of states and the convergence towards the bulk spectrum with dot size is investigated. Our calculations show that: (1) edge states appear in the band gap, (2) that there are a larger number of electronic states in the conduction band as compared to the valence band, and (3) the relative number of edge states decreases with increasing dot size.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Lancaster, Pa Editor
  Language Wos 000352591200005 Publication Date 2015-04-11
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1098-0121; 1550-235x ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 3.836 Times cited 44 Open Access
  Notes ; This work was supported by the Flemish Science Foundation (FWO-VI) and the Methusalem Foundation of the Flemish government. Stefan Pavlovic is supported by JoinEU-SEE IV, Erasmus Mundus Action 2 programme. We thank J. M. Pereira for interesting discussions. ; Approved Most recent IF: 3.836; 2015 IF: 3.736
  Call Number UA @ lucian @ c:irua:132516 Serial 4170
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Author Hannibal, S.; Kettmann, P.; Croitoru, M.D.; Vagov, A.; Axt, V.M.; Kuhn, T.
  Title Quench dynamics of an ultracold Fermi gas in the BCS regime : spectral properties and confinement-induced breakdown of the Higgs mode Type A1 Journal article
  Year 2015 Publication Physical review : A : atomic, molecular and optical physics Abbreviated Journal Phys Rev A
  Volume 91 Issue (down) 91 Pages 043630
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract The Higgs amplitude mode of the order parameter of an ultracold confined Fermi gas in the BCS regime after a quench of the coupling constant is analyzed theoretically. A characteristic feature is a damped oscillation which at a certain transition time changes into a rather irregular dynamics. We compare the numerical solution of the full set of nonlinear equations of motion for the normal and anomalous Bogoliubov quasiparticle excitations with a linearized approximation. In doing so the transition time as well as the difference between resonant systems, i.e., systems where the Fermi energy is close to a sub-band minimum, and off-resonant systems can be well understood and traced back to the system and geometry parameters.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Lancaster, Pa Editor
  Language Wos 000353448500005 Publication Date 2015-04-24
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1094-1622; 1050-2947 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 2.925 Times cited 10 Open Access
  Notes ; M.D.C. acknowledges support by the BELSPO Back to Belgium Grant. ; Approved Most recent IF: 2.925; 2015 IF: NA
  Call Number UA @ lucian @ c:irua:132509 Serial 4235
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Author Michel, K.H.; Costamagna; Peeters, F.M.
  Title Theory of anharmonic phonons in two-dimensional crystals Type A1 Journal article
  Year 2015 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
  Volume 91 Issue (down) 91 Pages 134302
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Anharmonic effects in an atomic monolayer thin crystal with honeycomb lattice structure are investigated by analytical and numerical lattice dynamical methods. Starting from a semiempirical model for anharmonic couplings of third and fourth orders, we study the in-plane and out-of-plane (flexural) mode components of the generalized wave vector dependent Gruneisen parameters, the thermal tension and the thermal expansion coefficients as a function of temperature and crystal size. From the resonances of the displacement-displacement correlation functions, we obtain the renormalization and decay rate of in-plane and flexural phonons as a function of temperature, wave vector, and crystal size in the classical and in the quantum regime. Quantitative results are presented for graphene. There, we find that the transition temperature T-alpha from negative to positive thermal expansion is lowered with smaller system size. Renormalization of the flexural mode has the opposite effect and leads to values of T-alpha approximate to 300 K for systems of macroscopic size. Extensive numerical analysis throughout the Brillouin zone explores various decay and scattering channels. The relative importance of normal and umklapp processes is investigated. The work is complementary to crystalline membrane theory and computational studies of anharmonic effects in two-dimensional crystals.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Lancaster, Pa Editor
  Language Wos 000353031000001 Publication Date 2015-04-17
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1098-0121; 1550-235x ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 3.836 Times cited 38 Open Access
  Notes ; We thank B. Verberck, D. Lamoen, and A. Dobry for useful comments. We acknowledge funding from the FWO (Belgium)-MINCyT (Argentina) collaborative research project. This work is supported by the EuroGRAPHENE project CONGRAN. ; Approved Most recent IF: 3.836; 2015 IF: 3.736
  Call Number UA @ lucian @ c:irua:132512 Serial 4263
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Author Lentijo-Mozo, S.; Tan, R.P.; Garcia-Marcelot, C.; Altantzis, T.; Fazzini, P.F.; Hungria, T.; Cormary, B.; Gallagher, J.R.; Miller, J.T.; Martinez, H.; Schrittwieser, S.; Schotter, J.; Respaud, M.; Bals, S.; Van Tendeloo, G.; Gatel, C.; Soulantica, K.
  Title Air- and water-resistant noble metal coated ferromagnetic cobalt nanorods Type A1 Journal article
  Year 2015 Publication ACS nano Abbreviated Journal Acs Nano
  Volume 9 Issue (down) 9 Pages 2792-2804
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
  Abstract Cobalt nanorods possess ideal magnetic properties for applications requiring magnetically hard nanoparticles. However, their exploitation is undermined by their sensitivity toward oxygen and water, which deteriorates their magnetic properties. The development of a continuous metal shell inert to oxidation could render them stable, opening perspectives not only for already identified applications but also for uses in which contact with air and/or aqueous media is inevitable. However, the direct growth of a conformal noble metal shell on magnetic metals is a challenge. Here, we show that prior treatment of Co nanorods with a tin coordination compound is the crucial step that enables the subsequent growth of a continuous noble metal shell on their surface, rendering them air- and water-resistant, while conserving the monocrystallity, metallicity and the magnetic properties of the Co core. Thus, the as-synthesized coreshell ferromagnetic nanorods combine high magnetization and strong uniaxial magnetic anisotropy, even after exposure to air and water, and hold promise for successful implementation in in vitro biodiagnostics requiring probes of high magnetization and anisotropic shape.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000351791800055 Publication Date 2015-03-03
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1936-0851;1936-086X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 13.942 Times cited 25 Open Access OpenAccess
  Notes 312483 Esteem2; 246791 Countatoms; 335078 Colouratom; esteem2ta; ECASSara; (ROMEO:white; preprint:; postprint:restricted 12 months embargo; pdfversion:cannot); Approved Most recent IF: 13.942; 2015 IF: 12.881
  Call Number c:irua:125380 c:irua:125380 Serial 87
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Author Javon, E.; Gaceur, M.; Dachraoui, W.; Margeat, O.; Ackermann, J.; Ilenia Saba, M.; Delugas, P.; Mattoni, A.; Bals, S.; Van Tendeloo, G.
  Title Competing forces in the self-assembly of coupled ZnO nanopyramids Type A1 Journal article
  Year 2015 Publication ACS nano Abbreviated Journal Acs Nano
  Volume 9 Issue (down) 9 Pages 3685-3694
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
  Abstract Self-assembly (SA) of nanostructures has recently gained increasing interest. A clear understanding of the process is not straightforward since SA of nanoparticles is a complex multiscale phenomenon including different driving forces. Here, we study the SA between aluminum doped ZnO nanopyramids into couples by combining inorganic chemistry and advanced electron microscopy techniques with atomistic simulations. Our results show that the SA of the coupled nanopyramids is controlled first by morphology, as coupling only occurs in the case of pyramids with well-developed facets of the basal planes. The combination of electron microscopy and atomistic modeling reveals that the coupling is further driven by strong ligandligand interaction between the bases of the pyramids as dominant force, while screening effects due to Al doping or solvent as well as corecore interaction are only minor contributions. Our combined approach provides a deeper understanding of the complex interplay between the interactions at work in the coupled SA of ZnO nanopyramids.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000353867000030 Publication Date 2015-03-12
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1936-0851;1936-086X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 13.942 Times cited 21 Open Access OpenAccess
  Notes Esmi; 335078 Colouratom; ECAS_Sara; (ROMEO:white; preprint:; postprint:restricted 12 months embargo; pdfversion:cannot); Approved Most recent IF: 13.942; 2015 IF: 12.881
  Call Number c:irua:125978 Serial 434
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Author Chen, B.; Sahin, H.; Suslu, A.; Ding, L.; Bertoni, M.I.; Peeters, F.M.; Tongay, S.
  Title Environmental changes in MoTe2 excitonic dynamics by defects-activated molecular interaction Type A1 Journal article
  Year 2015 Publication ACS nano Abbreviated Journal Acs Nano
  Volume 9 Issue (down) 9 Pages 5326-5332
  Keywords A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
  Abstract Monolayers of group VI transition metal dichalcogenides possess direct gaps in the visible spectrum with the exception of MoTe2, where its gap is suitably located in the infrared region but its stability is of particular interest, as tellurium compounds are acutely sensitive to oxygen exposure. Here, our environmental (time-dependent) measurements reveal two distinct effects on MoTe2 monolayers: For weakly luminescent monolayers, photoluminescence signal and optical contrast disappear, as if they are decomposed, but yet remain intact as evidenced by AFM and Raman measurements. In contrast, strongly luminescent monolayers retain their optical contrast for a prolonged amount of time, while their PL peak blue-shifts and PL intensity saturates to slightly lower values. Our X-ray photoelectron spectroscopy measurements and DFT calculations suggest that the presence of defects and functionalization of these defect sites with O-2 molecules strongly dictate their material properties and aging response by changing the excitonic dynamics due to deep or shallow states that are created within the optical band gap. Presented results not only shed light on environmental effects on fundamental material properties and excitonic dynamics of MoTe2 monolayers but also highlight striking material transformation for metastable 20 systems such as WTe2, silicone, and phosphorene.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000355383000068 Publication Date 2015-04-14
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1936-0851;1936-086X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 13.942 Times cited 150 Open Access
  Notes ; This work was supported by the Arizona State University seeding program. The authors thank Hui Cai and Kedi Wu for useful discussions. We gratefully acknowledge the use of facilities at the LeRoy Eyring Center for Solid State Science at Arizona State University. This work was supported by the Flemish Science Foundation (FWO-VI) and the Methusalem Foundation of the Flemish government. H.S. is supported by a FWO Pegasus Long Marie Curie Fellowship. ; Approved Most recent IF: 13.942; 2015 IF: 12.881
  Call Number c:irua:126441 Serial 1068
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Author Sanz-Ortiz, M.N.; Sentosun, K.; Bals, S.; Liz-Marzan, L.M.
  Title Templated Growth of Surface Enhanced Raman Scattering -Active Branched Au Nanoparticles within Radial Mesoporous Silica Shells Type A1 Journal article
  Year 2015 Publication ACS nano Abbreviated Journal Acs Nano
  Volume 9 Issue (down) 9 Pages 10489-10497
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
  Abstract Noble metal nanoparticles are widely used as probes or substrates for surface-enhanced Raman scattering (SERS), due to their characteristic plasmon resonances in the visible and NIR spectral ranges. Aiming at obtaining a versatile system with high SERS performance we developed the synthesis of quasi-monodisperse, non-aggregated gold nanoparticles protected by radial mesoporous silica shells. The radial channels of such shells were used as templates for the growth of gold tips branching from the cores, thereby improving the plasmonic performance of the particles while favoring the localization of analyte molecules at high electric field regions: close to the tips, inside the pores. The method, which allows control over tip length, was successfully applied to various gold nanoparticle shapes, leading to materials with highly efficient SERS performance. The obtained nanoparticles are stable in ethanol and water upon thermal consolidation and can be safely stored as a powder.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language English Wos 000363915300105 Publication Date 2015-09-15
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1936-0851;1936-086X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 13.942 Times cited 110 Open Access OpenAccess
  Notes This work has been funded by the European Research Council (ERC Advanced Grant 267867 Plasmaquo and Starting Grant Colouratom). The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013 under grant agreement no. 312184, SACS). Help from Mert Kurttepeli is acknowledged. Pentatwinned nanorods and nanotriangles were synthesized by L. Scarabelli.; ECAS_Sara; (ROMEO:white; preprint:; postprint:restricted 12 months embargo; pdfversion:cannot); Approved Most recent IF: 13.942; 2015 IF: 12.881
  Call Number c:irua:129194 Serial 3947
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Author Yan, Y.; Zhou, X.; Jin, H.; Li, C.-Z.; Ke, X.; Van Tendeloo, G.; Liu, K.; Yu, D.; Dressel, M.; Liao, Z.-M.
  Title Surface-Facet-Dependent Phonon Deformation Potential in Individual Strained Topological Insulator Bi2Se3 Nanoribbons Type A1 Journal article
  Year 2015 Publication ACS nano Abbreviated Journal Acs Nano
  Volume 9 Issue (down) 9 Pages 10244-10251
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
  Abstract Strain is an important method to tune the properties of topological insulators. For example, compressive strain can induce superconductivity in Bi2Se3 bulk material. Topological insulator nanostructures are the superior candidates to utilize the unique surface states due to the large surface to volume ratio. Therefore, it is highly desirable to monitor the local strain effects in individual topological insulator nanostructures. Here, we report the systematical micro-Raman spectra of single strained Bi2Se3 nanoribbons with different thicknesses and different surface facets, where four optical modes are resolved in both Stokes and anti-Stokes Raman spectral lines. A striking anisotropy of the strain dependence is observed in the phonon frequency of strained Bi2Se3 nanoribbons grown along the ⟨112̅0⟩ direction. The frequencies of the in-plane Eg2 and out-of-plane A1g1 modes exhibit a nearly linear blue-shift against bending strain when the nanoribbon is bent along the ⟨112̅0⟩ direction with the curved {0001} surface. In this case, the phonon deformation potential of the Eg2 phonon for 100 nm-thick Bi2Se3 nanoribbon is up to 0.94 cm–1/%, which is twice of that in Bi2Se3 bulk material (0.52 cm–1/%). Our results may be valuable for the strain modulation of individual topological insulator nanostructures.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language English Wos 000363915300079 Publication Date 2015-09-12
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1936-0851;1936-086X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 13.942 Times cited 14 Open Access
  Notes Y.Y. would like to thank Xuewen Fu for helpful discussions. This work was supported by MOST (Nos. 2013CB934600, 2013CB932602) and NSFC (Nos. 11274014, 11234001). Approved Most recent IF: 13.942; 2015 IF: 12.881
  Call Number c:irua:129216 Serial 3963
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Author Nerantzaki, M.; Filippousi, M.; Van Tendeloo, G.; Terzopoulou, Z.; Bikiaris, D.; Goudouri, O.M.; Detsch, R.; Grueenewald, A.; Boccaccini, A.R.
  Title Novel poly(butylene succinate) nanocomposites containing strontium hydroxyapatite nanorods with enhanced osteoconductivity for tissue engineering applications Type A1 Journal article
  Year 2015 Publication Express polymer letters Abbreviated Journal Express Polym Lett
  Volume 9 Issue (down) 9 Pages 773-789
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract Three series of poly(butylene succinate) (PBSu) nanocomposites containing 0.5, 1 and 2.5 wt% strontium hydroxyapatite [Sr-5(PO4)(3)OH] nanorods (SrHAp nrds) were prepared by in situ polymerisation. The structural effects of Sr-5(PO4)(3)OH nanorods, for the different concentrations, inside the polymeric matrix (PBSu), were studied through high angle annular dark field scanning transmission electron microscopy (HAADF-STEM). HAADF-STEM measurements revealed that the SrHAp nanorods at low concentrations are dispersed inside the polymeric PBSu matrix while in 1 wt% some aggregates are formed. These aggregations affect the mechanical properties giving an enhancement for the concentration of 0.5 wt% SrHAp nrds in tensile strength, while a reduction is recorded for higher loadings of the nanofiller. Studies on enzymatic hydrolysis revealed that all nanocomposites present higher hydrolysis rates than neat PBSu, indicating that nanorods accelerate the hydrolysis degradation process. In vitro bioactivity tests prove that SrHAp nrds promote the formation of hydroxyapatite on the PBSu surface. All nanocomposites were tested also in relevant cell culture using osteoblast-like cells (MG-63) to demonstrate their biocompatibility showing SrHAp nanorods support cell attachment.
  Address
  Corporate Author Thesis
  Publisher Budapest University of Technology and Economics Department of Polymer Engineering Place of Publication Budapest, Hungary Editor
  Language Wos 000357287800004 Publication Date 2015-06-25
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1788-618X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 2.983 Times cited 21 Open Access
  Notes 262348 Esmi Approved Most recent IF: 2.983; 2015 IF: 2.761
  Call Number c:irua:127009 Serial 2382
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Author Chen, J.J.; Wang, Q.; Meng, J.; Ke, X.; Van Tendeloo, G.; Bie, Y.Q.; Liu, J.; Liu, K.; Liao, Z.M.; Sun, D.; Yu, D.;
  Title Photovoltaic effect and evidence of carrier multiplication in graphene vertical homojunctions with asymmetrical metal contacts Type A1 Journal article
  Year 2015 Publication ACS nano Abbreviated Journal Acs Nano
  Volume 9 Issue (down) 9 Pages 8851-8858
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
  Abstract Graphene exhibits exciting potentials for high-speed wideband photodetection and high quantum efficiency solar energy harvest because of its broad spectral absorption, fast photoelectric response, and potential carrier multiplication. Although photocurrent can be generated near a metalgraphene interface in lateral devices, the photoactive area is usually limited to a tiny one-dimensional line-like interface region. Here, we report photoelectric devices based on vertical graphene two-dimensional homojunction, which is fabricated via vertically stacking four graphene monolayers with asymmetric metal contacts. The devices show excellent photovoltaic output with excitation wavelength ranging from visible light to mid-infrared. The wavelength dependence of the internal quantum efficiency gives direct evidence of the carrier multiplication effect in graphene. The simple fabrication process, easy scale-up, large photoresponsive active area, and broadband response of the vertical graphene device are very promising for practical applications in optoelectronics and photovoltaics.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000361935800023 Publication Date 2015-08-15
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1936-0851;1936-086X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 13.942 Times cited 11 Open Access
  Notes 246791 Countatoms Approved Most recent IF: 13.942; 2015 IF: 12.881
  Call Number c:irua:127689 Serial 2615
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Author Ghosh, S.; Gaspari, R.; Bertoni, G.; Spadaro, M.C.; Prato, M.; Turner, S.; Cavalli, A.; Manna, L.; Brescia, R.
  Title Pyramid-Shaped Wurtzite CdSe Nanocrystals with Inverted Polarity Type A1 Journal article
  Year 2015 Publication ACS nano Abbreviated Journal Acs Nano
  Volume 9 Issue (down) 9 Pages 8537-8546
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
  Abstract We report on pyramid-shaped wurtzite cadmium selenide (CdSe) nanocrystals (NCs), synthesized by hot injection in the presence of chloride ions as shape-directing agents, exhibiting reversed crystal polarity compared to former reports. Advanced transmission electron microscopy (TEM) techniques (image-corrected high-resolution TEM with exit wave reconstruction and probe-corrected high-angle annular dark field-scanning TEM) unequivocally indicate that the triangular base of the pyramids is the polar (0001) facet and their apex points toward the [0001] direction. Density functional theory calculations, based on a simple model of binding of Cl(-) ions to surface Cd atoms, support the experimentally evident higher thermodynamic stability of the (0001) facet over the (0001) one conferred by Cl(-) ions. The relative stability of the two polar facets of wurtzite CdSe is reversed compared to previous experimental and computational studies on Cd chalcogenide NCs, in which no Cl-based chemicals were deliberately used in the synthesis or no Cl(-) ions were considered in the binding models. Self-assembly of these pyramids in a peculiar clover-like geometry, triggered by the addition of oleic acid, suggests that the basal (polar) facet has a density and perhaps type of ligands significantly different from the other three facets, since the pyramids interact with each other exclusively via their lateral facets. A superstructure, however with no long-range order, is observed for clovers with their (0001) facets roughly facing each other. The CdSe pyramids were also exploited as seeds for CdS pods growth, and the peculiar shape of the derived branched nanostructures clearly arises from the inverted polarity of the seeds.
  Address Department of Nanochemistry, Istituto Italiano di Tecnologia (IIT) , via Morego 30, I-16163 Genova, Italy
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language English Wos 000360323300085 Publication Date 2015-07-23
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1936-0851;1936-086X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 13.942 Times cited 16 Open Access
  Notes PMID:26203791 Approved Most recent IF: 13.942; 2015 IF: 12.881
  Call Number c:irua:127807 Serial 3956
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Author Ozkan, A.; Dufour, T.; Arnoult, G.; De Keyzer, P.; Bogaerts, A.; Reniers, F.
  Title CO2-CH4 conversion and syngas formation at atmospheric pressure using a multi-electrode dielectric barrier discharge Type A1 Journal article
  Year 2015 Publication Journal of CO2 utilization Abbreviated Journal J Co2 Util
  Volume 9 Issue (down) 9 Pages 74-81
  Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
  Abstract The conversion of CO2 and CH4 into value-added chemicals is studied in a new geometry of a dielectric barrier discharge (DBD) with multi-electrodes, dedicated to the treatment of high gas flow rates. Gas chromatography is used to define the CO2 and CH4 conversion as well as the yields of the products of decomposition (CO, O2 and H2) and of recombination (C2H4, C2H6 and CH2O). The influence of three parameters is investigated on the conversion: the CO2 and CH4 flow rates, the plasma power and the nature of the carrier gas (argon or helium). The energy efficiency of the CO2 conversion is estimated and compared with those of similar atmospheric plasma sources. Our DBD reactor shows a good compromise between a good energy efficiency and the treatment of a large CO2 flow rate.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000350088700010 Publication Date 2015-01-28
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 2212-9820; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 4.292 Times cited 57 Open Access
  Notes Approved Most recent IF: 4.292; 2015 IF: 3.091
  Call Number c:irua:123029 Serial 3522
Permanent link to this record
 

 
Author van der Stam, W.; Bladt, E.; Rabouw, F.T.; Bals, S.; de Mello Donega, C.
  Title Near-Infrared Emitting CuInSe/CuInS Dot Core/Rod Shell Heteronanorods by Sequential Cation Exchange Type A1 Journal article
  Year 2015 Publication ACS nano Abbreviated Journal Acs Nano
  Volume 9 Issue (down) 9 Pages 11430-11438
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
  Abstract The direct synthesis of heteronanocrystals (HNCs) combining different ternary semiconductors is challenging and has not yet been successful. Here, we report a sequential topotactic cation exchange (CE) pathway that yields CuInSe2/CuInS2 dot core/rod shell nanorods with near-infrared luminescence. In our approach, the Cu+ extraction rate is coupled to the In3+ incorporation rate by the use of a stoichiometric trioctylphosphine-InCl3 complex, which fulfills the roles of both In-source and Cu-extracting agent. In this way, Cu+ ions can be extracted by trioctylphosphine ligands only when the In-P bond is broken. This results in readily available In3+ ions at the same surface site from which the Cu+ is extracted, making the process a direct place exchange reaction and shifting the overall energy balance in favor of the CE. Consequently, controlled cation exchange can occur even in large and anisotropic heterostructured nanocrystals with preservation of the size, shape, and heterostructuring of the template NCs into the product NCs. The cation exchange is self-limited, stopping when the ternary core/shell CuInSe2/CuInS2 composition is reached. The method is very versatile, successfully yielding a variety of luminescent CuInX2 (X = S, Se, and Te) quantum dots, nanorods, and HNCs, by using Cd-chalcogenide NCs and HNCs as templates. The approach reported here thus opens up routes toward materials with unprecedented properties, which would otherwise remain inaccessible.
  Address Debye Institute for Nanomaterials Science, Utrecht University , P.O. Box 80000, 3508 TA Utrecht, The Netherlands
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language English Wos 000365464800094 Publication Date 2015-10-09
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1936-0851;1936-086X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 13.942 Times cited 88 Open Access OpenAccess
  Notes The authors thank Gang Wang for XRD measurements and Eline Hutter for providing CdSe/CdS NRs. W.v.d.S. and C.d.M.D. acknowledge financial support from the division of Chemical Sciences (CW) of The Netherlands Organization for Scientific Research (NWO) under grant number ECHO.712.012.001. This work was supported by the European Research Council (ERC Starting Grant #335078 Colouratom). E.B. gratefully acknowledges financial support by the Flemish Fund for Scientific Research (FWO Vlaanderen).; ECAS_Sara; (ROMEO:white; preprint:; postprint:restricted 12 months embargo; pdfversion:cannot); Approved Most recent IF: 13.942; 2015 IF: 12.881
  Call Number c:irua:129184 Serial 3948
Permanent link to this record
 

 
Author Neyts, E.C.
  Title The role of ions in plasma catalytic carbon nanotube growth : a review Type A1 Journal article
  Year 2015 Publication Frontiers of Chemical Science and Engineering Abbreviated Journal Front Chem Sci Eng
  Volume 9 Issue (down) 9 Pages 154-162
  Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
  Abstract While it is well-known that the plasma-enhanced catalytic chemical vapor deposition (PECVD) of carbon nanotubes (CNTs) offers a number of advantages over thermal CVD, the influence of the various individual contributing factors is not well understood. Especially the role of ions is unclear, since ions in plasmas are generally associated with sputtering rather than with growing a material. Even so, various studies have demonstrated the beneficial effects of ion bombardment during the growth of CNTs. This review looks at the role of the ions in plasma-enhanced CNT growth as deduced from both experimental and simulation studies. Specific attention is paid to the beneficial effects of ion bombardment. Based on the available literature, it can be concluded that ions can be either beneficial or detrimental for carbon nanotube growth, depending on the exact conditions and the control over the growth process.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000360319600003 Publication Date 2015-06-11
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 2095-0179 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 1.712 Times cited 8 Open Access
  Notes Approved Most recent IF: 1.712; 2015 IF: NA
  Call Number UA @ lucian @ c:irua:127815 Serial 4239
Permanent link to this record
 

 
Author De Schepper, E.; Lizin, S.; Durlinger, B.; Azadi, H.; Van Passel, S.
  Title Economic and environmental performances of small-scale rural PV solar projects under the clean development mechanism : the case of Cambodia Type A1 Journal article
  Year 2015 Publication Energies Abbreviated Journal Energies
  Volume 8 Issue (down) 9 Pages 9892-9914
  Keywords A1 Journal article; Engineering sciences. Technology; Engineering Management (ENM)
  Abstract The two core objectives of the Clean Development Mechanism (CDM) are cost-effective emission reduction and sustainable development. Despite the potential to contribute to both objectives, solar projects play a negligible role under the CDM. In this research, the greenhouse gas mitigation cost is used to evaluate the economic and environmental performances of small-scale rural photovoltaic solar projects. In particular, we compare the use of absolute and relative mitigation costs to evaluate the attractiveness of these projects under the CDM. We encourage the use of relative mitigation costs, implying consideration of baseline costs that render the projects profitable. Results of the mitigation cost analysis are dependent on the baseline chosen. To overcome this drawback, we complement the analysis with a multi-objective optimization approach, which allows quantifying the trade-off between economic and environmental performances of the optimal technologies without requiring a baseline.
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  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000362553000046 Publication Date 2015-09-15
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1996-1073 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 2.262 Times cited 6 Open Access
  Notes ; ; Approved Most recent IF: 2.262; 2015 IF: 2.072
  Call Number UA @ admin @ c:irua:129426 Serial 6187
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