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Author Komendová, L.; Milošević, M.V.; Peeters, F.M.
Title Soft vortex matter in a type-I/type-II superconducting bilayer Type A1 Journal article
Year (up) 2013 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 88 Issue 9 Pages 094515
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Magnetic flux patterns are known to strongly differ in the intermediate state of type-I and type-II superconductors. Using a type-I/type-II bilayer we demonstrate hybridization of these flux phases into a plethora of unique new ones. Owing to a complicated multibody interaction between individual fluxoids, many different intriguing patterns are possible under applied magnetic field, such as few-vortex clusters, vortex chains, mazes, or labyrinthal structures resembling the phenomena readily encountered in soft-matter physics. However, in our system the patterns are tunable by sample parameters, magnetic field, current, and temperature, which reveals transitions from short-range clustering to long-range ordered phases such as parallel chains, gels, glasses, and crystalline vortex lattices, or phases where lamellar type-I flux domains in one layer serve as a bedding potential for type-II vortices in the other, configurations clearly beyond the soft-matter analogy.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000324689900008 Publication Date 2013-09-24
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 27 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl). Insightful discussions with Arkady Shanenko and Edith Cristina Euan Diaz are gratefully acknowledged. ; Approved Most recent IF: 3.836; 2013 IF: 3.664
Call Number UA @ lucian @ c:irua:111167 Serial 3050
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Author Villegas, C.E.P.; Tavares, M.R.S.; Hai, G.-Q.; Peeters, F.M.
Title Sorting the modes contributing to guidance in strain-induced graphene waveguides Type A1 Journal article
Year (up) 2013 Publication New journal of physics Abbreviated Journal New J Phys
Volume 15 Issue Pages 023015-11
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We propose a simple way of probing the number of modes contributing to the channeling in graphene waveguides which are formed by a gauge potential produced by mechanical strain. The energy mode structure for both homogeneous and non-homogeneous strain regimes is carefully studied using the continuum description of the Dirac equation. We found that high strain values privilege negative (instead of positive) group velocities throughout the guidance, sorting the types of modes flowing through it. We also show how the effect of a substrate-induced gap competes against the strain.
Address
Corporate Author Thesis
Publisher Place of Publication Bristol Editor
Language Wos 000314868000002 Publication Date 2013-02-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1367-2630; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.786 Times cited 7 Open Access
Notes ; This work was supported by FAPESP, CNPq and the Flemish Science Foundation (FWO-VI). ; Approved Most recent IF: 3.786; 2013 IF: 3.671
Call Number UA @ lucian @ c:irua:107667 Serial 3056
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Author Alekseeva, A.M.; Abakumov, A.M.; Leither-Jasper, A.; Schnelle, W.; Prots, Y.; Van Tendeloo, G.; Antipov, E.V.; Grin, Y.
Title Spatial separation of covalent, ionic, and metallic interactions in Mg11Rh18B8 and Mg3Rh5B3 Type A1 Journal article
Year (up) 2013 Publication Chemistry: a European journal Abbreviated Journal Chem-Eur J
Volume 19 Issue 52 Pages 17860-17870
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The crystal structures of Mg11Rh18B8 and Mg3Rh5B3 have been investigated by using single-crystal X-ray diffraction. Mg11Rh18B8: space group P4/mbm; a=17.9949(7), c=2.9271(1)angstrom; Z=2. Mg3Rh5B3: space group Pmma; a=8.450(2), b=2.8644(6), c=11.602(2)angstrom; Z=2. Both crystal structures are characterized by trigonal prismatic coordination of the boron atoms by rhodium atoms. The [BRh6] trigonal prisms form arrangements with different connectivity patterns. Analysis of the chemical bonding by means of the electron-localizability/electron-density approach reveals covalent BRh interactions in these arrangements and the formation of BRh polyanions. The magnesium atoms that are located inside the polyanions interact ionically with their environment, whereas, in the structure parts, which are mainly formed by Mg and Rh atoms, multicenter (metallic) interactions are observed. Diamagnetic behavior and metallic electron transport of the Mg11Rh18B8 and Mg3Rh5B3 phases are in agreement with the bonding picture and the band structure.
Address
Corporate Author Thesis
Publisher Place of Publication Weinheim Editor
Language Wos 000328531000028 Publication Date 2013-12-02
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0947-6539; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 5.317 Times cited 5 Open Access
Notes Approved Most recent IF: 5.317; 2013 IF: 5.696
Call Number UA @ lucian @ c:irua:113697 Serial 3064
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Author Zhang, S.; Van Gaens, W.; van Gessel, B.; Hofmann, S.; van Veldhuizen, E.; Bogaerts, A.; Bruggeman, P.
Title Spatially resolved ozone densities and gas temperatures in a time modulated RF driven atmospheric pressure plasma jet : an analysis of the production and destruction mechanisms Type A1 Journal article
Year (up) 2013 Publication Journal of physics: D: applied physics Abbreviated Journal J Phys D Appl Phys
Volume 46 Issue 20 Pages 205202-205212
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract In this work, a time modulated RF driven DBD-like atmospheric pressure plasma jet in Ar + 2%O2, operating at a time averaged power of 6.5 W is investigated. Spatially resolved ozone densities and gas temperatures are obtained by UV absorption and Rayleigh scattering, respectively. Significant gas heating in the core of the plasma up to 700 K is found and at the position of this increased gas temperature a depletion of the ozone density is found. The production and destruction reactions of O3 in the jet effluent as a function of the distance from the nozzle are obtained from a zero-dimensional chemical kinetics model in plug flow mode which considers relevant air chemistry due to air entrainment in the jet fluent. A comparison of the measurements and the models show that the depletion of O3 in the core of the plasma is mainly caused by an enhanced destruction of O3 due to a large atomic oxygen density.
Address
Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos 000318546100008 Publication Date 2013-05-02
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-3727;1361-6463; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.588 Times cited 74 Open Access
Notes Approved Most recent IF: 2.588; 2013 IF: 2.521
Call Number UA @ lucian @ c:irua:107840 Serial 3067
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Author Milovanović, S.P.; Masir, M.R.; Peeters, F.M.
Title Spectroscopy of snake states using a graphene Hall bar Type A1 Journal article
Year (up) 2013 Publication Applied physics letters Abbreviated Journal Appl Phys Lett
Volume 103 Issue 23 Pages 233502-233504
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract An approach to observe snake states in a graphene Hall bar containing a pn-junction is proposed. The magnetic field dependence of the bend resistance in a ballistic graphene Hall bar structure containing a tilted pn-junction oscillates as a function of applied magnetic field. We show that each oscillation is due to a specific snake state that moves along the pn-interface. Furthermore, depending on the value of the magnetic field and applied potential, we can control the lead in which the electrons will end up and hence control the response of the system.
Address
Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000328634900090 Publication Date 2013-12-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-6951; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.411 Times cited 15 Open Access
Notes This work was supported by the Flemish Science Foundation (FWO-Vl), the European Science Foundation (ESF) under the EUROCORES Program EuroGRAPHENE within the project CONGRAN and the Methusalem Foundation of the Flemish government. Approved Most recent IF: 3.411; 2013 IF: 3.515
Call Number UA @ lucian @ c:irua:113710 Serial 3074
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Author Van Boxem, R.; Verbeeck, J.; Partoens, B.
Title Spin effects in electron vortex states Type A1 Journal article
Year (up) 2013 Publication Europhysics letters Abbreviated Journal Epl-Europhys Lett
Volume 102 Issue 4 Pages 40010-40016
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Abstract The recent experimental realization of electron vortex beams opens up a wide research domain previously unexplored. The present paper explores the relativistic properties of these electron vortex beams, and quantifies deviations from the scalar wave theory. It is common in electron optics to use the Schrodinger equation neglecting spin. The present paper investigates the role of spin and the total angular momentum J(z) and how it pertains to the vortex states. As an application, we also investigate if it is possible to use holographic reconstruction to create novel total angular momentum eigenstates in a transmission electron microscope. It is demonstrated that relativistic spin coupling effects disappear in the paraxial limit, and spin effects in holographically created electron vortex beams can only be exploited by using specialized magnetic apertures.
Address
Corporate Author Thesis
Publisher Place of Publication Paris Editor
Language Wos 000321118600011 Publication Date 2013-06-11
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0295-5075;1286-4854; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.957 Times cited 11 Open Access
Notes 312483 Esteem2; N246791 Countatoms; 278510 Vortex; esteem2jra1; esteem2jra3 ECASJO_; Approved Most recent IF: 1.957; 2013 IF: 2.269
Call Number UA @ lucian @ c:irua:109852 Serial 3087
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Author Badalyan, S.M.; Matos-Abiague, A.; Fabian, J.; Vignale, G.; Peeters, F.M.
Title Spin-orbit-interaction induced singularity of the charge density relaxation propagator Type A1 Journal article
Year (up) 2013 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 88 Issue 19 Pages 195402-195405
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The charge density relaxation propagator of a two-dimensional electron system, which is the slope of the imaginary part of the polarization function, exhibits singularities for bosonic momenta having the order of the spin-orbit momentum and depending on the momentum orientation. We have provided an intuitive understanding for this nonanalytic behavior in terms of the interchirality subband electronic transitions, induced by the combined action of Bychkov-Rashba (BR) and Dresselhaus (D) spin-orbit coupling. It is shown that the regular behavior of the relaxation propagator is recovered in the presence of only one BR or D spin-orbit field or for spin-orbit interaction with equal BR and D coupling strengths. This creates a new possibility to influence carrier relaxation properties by means of an applied electric field.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000326820200005 Publication Date 2013-11-07
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 ; We acknowledge support from the Methusalem program of the Flemish government and the Flemish Science Foundation (FWO-Vl), DFG SFB Grant 689, and NSF Grant DMR-1104788 (G.V.). ; Approved Most recent IF: 3.836; 2013 IF: 3.664
Call Number UA @ lucian @ c:irua:112711 Serial 3093
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Author Neek-Amal, M.; Beheshtian, J.; Shayeganfar, F.; Singh, S.K.; Los, J.H.; Peeters, F.M.
Title Spiral graphone and one-sided fluorographene nanoribbons Type A1 Journal article
Year (up) 2013 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 87 Issue 7 Pages 075448-8
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The instability of a free-standing one-sided hydrogenated/fluorinated graphene nanoribbon, i.e., graphone/fluorographene, is studied using ab initio, semiempirical, and large-scale molecular dynamics simulations. Free-standing semi-infinite armchairlike hydrogenated/fluorinated graphene (AC-GH/AC-GF) and boatlike hydrogenated/fluorinated graphene (B-GH/B-GF) (nanoribbons which are periodic along the zigzag direction) are unstable and spontaneously transform into spiral structures. We find that rolled, spiral B-GH and B-GF are energetically more favorable than spiral AC-GH and AC-GF which is opposite to the double-sided flat hydrogenated/fluorinated graphene, i.e., graphane/fluorographene. We found that the packed, spiral structures exhibit an unexpected localized highest occupied molecular orbital and lowest occupied molecular orbital at the edges with increasing energy gap during rolling. These rolled hydrocarbon structures are stable beyond room temperature up to at least T = 1000 K within our simulation time of 1 ns. DOI: 10.1103/PhysRevB.87.075448
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000315481800005 Publication Date 2013-02-27
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 14 Open Access
Notes ; We thank A. Sadeghi, M. R. Ejtehadi, and J. Amini for their useful comments. This work is supported by the ESF EuroGRAPHENE project CONGRAN and the Flemish Science Foundation (FWO-Vl). M.N.-A. is supported by a EU-Marie Curie IIF fellowship program Grant No. 299855. ; Approved Most recent IF: 3.836; 2013 IF: 3.664
Call Number UA @ lucian @ c:irua:107654 Serial 3106
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Author Schoeters, B.; Neyts, E.C.; Khalilov, U.; Pourtois, G.; Partoens, B.
Title Stability of Si epoxide defects in Si nanowires : a mixed reactive force field/DFT study Type A1 Journal article
Year (up) 2013 Publication Physical chemistry, chemical physics Abbreviated Journal Phys Chem Chem Phys
Volume 15 Issue 36 Pages 15091-15097
Keywords A1 Journal article; Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Modeling the oxidation process of silicon nanowires through reactive force field based molecular dynamics simulations suggests that the formation of Si epoxide defects occurs both at the Si/SiOx interface and at the nanowire surface, whereas for flat surfaces, this defect is experimentally observed to occur only at the interface as a result of stress. In this paper, we argue that the increasing curvature stabilizes the defect at the nanowire surface, as suggested by our density functional theory calculations. The latter can have important consequences for the opto-electronic properties of thin silicon nanowires, since the epoxide induces an electronic state within the band gap. Removing the epoxide defect by hydrogenation is expected to be possible but becomes increasingly difficult with a reduction of the diameter of the nanowires.
Address
Corporate Author Thesis
Publisher Place of Publication Cambridge Editor
Language Wos 000323520600029 Publication Date 2013-07-16
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 3 Open Access
Notes ; BS gratefully acknowledges financial support of the IWT, Institute for the Promotion of Innovation by Science and Technology in Flanders, via the SBO project “SilaSol”. This work was carried out 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 and the Universiteit Antwerpen. ; Approved Most recent IF: 4.123; 2013 IF: 4.198
Call Number UA @ lucian @ c:irua:110793 Serial 3130
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Author Massobrio, C.; Djimbi, D.M.; Matsubara, M.; Scipioni, R.; Boero, M.
Title Stability of Ge12C48 and Ge20C40 heterofullerenes : a first principles molecular dynamics study Type A1 Journal article
Year (up) 2013 Publication Chemical physics letters Abbreviated Journal Chem Phys Lett
Volume 556 Issue Pages 163-167
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract By using first-principles molecular dynamics, we address the issue of structural stability for the C-60 Ge-m(m) family of doped heterofullerenes through a set of calculations targeting C48Ge12 and C40Ge20. Three kinds of theoretical tools are employed: (a) static structural optimization, (b) a bonding analysis based on localized orbitals (Wannier wavefunctions and centers) and (c) first-principles molecular dynamics at finite temperature. This latter tool allows concluding that the segregated form of C40Ge20 is less stable than its Si-based counterpart. However, the non-segregated forms of C40Ge20 and C40Si20 have comparable stabilities at finite temperatures. (C) 2012 Elsevier B. V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000313644100032 Publication Date 2012-11-28
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0009-2614; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.815 Times cited 3 Open Access
Notes Approved Most recent IF: 1.815; 2013 IF: 1.991
Call Number UA @ lucian @ c:irua:110085 Serial 3132
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Author Lichtert, S.; Verbeeck, J.
Title Statistical consequences of applying a PCA noise filter on EELS spectrum images Type A1 Journal article
Year (up) 2013 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 125 Issue Pages 35-42
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Principal component analysis (PCA) noise filtering is a popular method to remove noise from experimental electron energy loss (EELS) spectrum images. Here, we investigate the statistical behaviour of this method by applying it on a simulated data set with realistic noise levels. This phantom data set provides access to the true values contained in the data set as well as to many different realizations of the noise. Using least squares fitting and parameter estimation theory, we demonstrate that even though the precision on the estimated parameters can be better as the CramérRao lower bound, a significant bias is introduced which can alter the conclusions drawn from experimental data sets. The origin of this bias is in the incorrect retrieval of the principal loadings for noisy data. Using an expression for the bias and precision of the singular values from literature, we present an evaluation criterion for these singular values based on the noise level and the amount of information present in the data set. This criterion can help to judge when to avoid PCA noise filtering in practical situations. Further we show that constructing elemental maps of PCA noise filtered data using the background subtraction method, does not guarantee an increase in the signal to noise ratio due to correlation of the spectral data as a result of the filtering process.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000314679700006 Publication Date 2012-10-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.843 Times cited 54 Open Access
Notes Fwo; Countatoms; Vortex; Esteem 312483; esteem2jra3 ECASJO; Approved Most recent IF: 2.843; 2013 IF: 2.745
Call Number UA @ lucian @ c:irua:105293 Serial 3153
Permanent link to this record
 
 
Author Sahin, H.; Sivek, J.; Li, S.; Partoens, B.; Peeters, F.M.
Title Stone-Wales defects in silicene : formation, stability, and reactivity of defect sites Type A1 Journal article
Year (up) 2013 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 88 Issue 4 Pages 045434-45436
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract During the synthesis of ultrathin materials with hexagonal lattice structure Stone-Wales (SW) type of defects are quite likely to be formed and the existence of such topological defects in the graphenelike structures results in dramatic changes of their electronic and mechanical properties. Here we investigate the formation and reactivity of such SW defects in silicene. We report the energy barrier for the formation of SW defects in freestanding (similar to 2.4 eV) and Ag(111)-supported (similar to 2.8 eV) silicene and found it to be significantly lower than in graphene (similar to 9.2 eV). Moreover, the buckled nature of silicene provides a large energy barrier for the healing of the SW defect and therefore defective silicene is stable even at high temperatures. Silicene with SW defects is semiconducting with a direct band gap of 0.02 eV and this value depends on the concentration of defects. Furthermore, nitrogen substitution in SW-defected silicene shows that the defect lattice sites are the least preferable substitution locations for the N atoms. Our findings show the easy formation of SW defects in silicene and also provide a guideline for band gap engineering in silicene-based materials through such defects.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000322113300007 Publication Date 2013-07-23
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 93 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Methusalem foundation of the Flemish government. Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure), and HPC infrastructure of the University of Antwerp (CalcUA) a division of the Flemish Supercomputer Center (VSC), which is funded by the Hercules foundation. H.S. is supported by a FWO Pegasus Marie Curie Fellowship. ; Approved Most recent IF: 3.836; 2013 IF: 3.664
Call Number UA @ lucian @ c:irua:109805 Serial 3162
Permanent link to this record
 
 
Author Arsoski, V.V.; Tadić, M.Z.; Peeters, F.M.
Title Strain and band-mixing effects on the excitonic Aharonov-Bohm effect in In(Ga)As/GaAs ringlike quantum dots Type A1 Journal article
Year (up) 2013 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 87 Issue 8 Pages 085314-14
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Neutral excitons in strained axially symmetric In(Ga)As/GaAs quantum dots with a ringlike shape are investigated. Similar to experimental self-assembled quantum rings, the analyzed quantum dots have volcano-like shapes. The continuum mechanical model is employed to determine the strain distribution, and the single-band envelope function approach is adopted to compute the electron states. The hole states are determined by the axially symmetric multiband Luttinger-Kohn Hamiltonian, and the exciton states are obtained from an exact diagonalization. We found that the presence of the inner layer covering the ring opening enhances the excitonic Aharonov-Bohm (AB) oscillations. The reason is that the hole becomes mainly localized in the inner part of the quantum dot due to strain, whereas the electron resides mainly inside the ring-shaped rim. Interestingly, larger AB oscillations are found in the analyzed quantum dot than in a fully opened quantum ring of the same width. Comparison with the unstrained ringlike quantum dot shows that the amplitude of the excitonic Aharonov-Bohm oscillations are almost doubled in the presence of strain. The computed oscillations of the exciton energy levels are comparable in magnitude to the oscillations measured in recent experiments. DOI: 10.1103/PhysRevB.87.085314
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000315278000003 Publication Date 2013-02-25
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 18 Open Access
Notes ; This work was supported by the EU NoE: SANDiE, the Ministry of Education, Science, and Technological Development of Serbia, and the Flemish Science Foundation (FWO-Vl). ; Approved Most recent IF: 3.836; 2013 IF: 3.664
Call Number UA @ lucian @ c:irua:107656 Serial 3165
Permanent link to this record
 
 
Author Béché, A.; Rouviere, J.L.; Barnes, J.P.; Cooper, D.
Title Strain measurement at the nanoscale : comparison between convergent beam electron diffraction, nano-beam electron diffraction, high resolution imaging and dark field electron holography Type A1 Journal article
Year (up) 2013 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 131 Issue Pages 10-23
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Convergent beam electron diffraction (CBED), nano-beam electron diffraction (NBED or NBD), high resolution imaging (HRTEM and HRSTEM) and dark field electron holography (DFEH or HoloDark) are five TEM based techniques able to quantitatively measure strain at the nanometer scale. In order to demonstrate the advantages and disadvantages of each technique, two samples composed of epitaxial silicon-germanium layers embedded in a silicon matrix have been investigated. The five techniques are then compared in terms of strain precision and accuracy, spatial resolution, field of view, mapping abilities and ease of performance and analysis. (C) 2013 Elsevier By. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000322631200002 Publication Date 2013-04-06
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.843 Times cited 73 Open Access
Notes Approved Most recent IF: 2.843; 2013 IF: 2.745
Call Number UA @ lucian @ c:irua:109774 Serial 3171
Permanent link to this record
 
 
Author Abakumov, A.M.; Batuk, M.; Tsirlin, A.A.; Tyablikov, O.A.; Sheptyakov, D.V.; Filimonov, D.S.; Pokholok, K.V.; Zhidal, V.S.; Rozova, M.G.; Antipov, E.V.; Hadermann, J.; Van Tendeloo, G.;
Title Structural and magnetic phase transitions in the AnBnO3n-2 anion-deficient perovskites Pb2Ba2BiFe5O13 and Pb1.5Ba2.5Bi2Fe6O16 Type A1 Journal article
Year (up) 2013 Publication Inorganic chemistry Abbreviated Journal Inorg Chem
Volume 52 Issue 14 Pages 7834-7843
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Novel anion-deficient perovskite-based ferrites Pb2Ba2BiFe5O13 and Pb1.5Ba2.5Bi2Fe6O16 were synthesized by solid-state reaction in air. Pb2Ba2BiFe5O13 and Pb1.5Ba2.5Bi2Fe6O16 belong to the perovskite-based AnBnO3n2 homologous series with n = 5 and 6, respectively, with a unit cell related to the perovskite subcell ap as ap√2 × ap × nap√2. Their structures are derived from the perovskite one by slicing it with 1/2[110]p(1̅01)p crystallographic shear (CS) planes. The CS operation results in (1̅01)p-shaped perovskite blocks with a thickness of (n 2) FeO6 octahedra connected to each other through double chains of edge-sharing FeO5 distorted tetragonal pyramids which can adopt two distinct mirror-related configurations. Ordering of chains with a different configuration provides an extra level of structure complexity. Above T ≈ 750 K for Pb2Ba2BiFe5O13 and T ≈ 400 K for Pb1.5Ba2.5Bi2Fe6O16 the chains have a disordered arrangement. On cooling, a second-order structural phase transition to the ordered state occurs in both compounds. Symmetry changes upon phase transition are analyzed using a combination of superspace crystallography and group theory approach. Correlations between the chain ordering pattern and octahedral tilting in the perovskite blocks are discussed. Pb2Ba2BiFe5O13 and Pb1.5Ba2.5Bi2Fe6O16 undergo a transition into an antiferromagnetically (AFM) ordered state, which is characterized by a G-type AFM ordering of the Fe magnetic moments within the perovskite blocks. The AFM perovskite blocks are stacked along the CS planes producing alternating FM and AFM-aligned FeFe pairs. In spite of the apparent frustration of the magnetic coupling between the perovskite blocks, all n = 4, 5, 6 AnFenO3n2 (A = Pb, Bi, Ba) feature robust antiferromagnetism with similar Néel temperatures of 623632 K.
Address
Corporate Author Thesis
Publisher Place of Publication Easton, Pa Editor
Language Wos 000322087100006 Publication Date 2013-02-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0020-1669;1520-510X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.857 Times cited 10 Open Access
Notes Countatoms Approved Most recent IF: 4.857; 2013 IF: 4.794
Call Number UA @ lucian @ c:irua:109213 Serial 3196
Permanent link to this record
 
 
Author Turner, S.; Lebedev, O.I.; Verbeeck, J.; Gehrke, K.; Moshnyaga, V.; Van Tendeloo, G.
Title Structural phase transition and spontaneous interface reconstruction in La2/3Ca1/3MnO3/BaTiO3 superlattices Type A1 Journal article
Year (up) 2013 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 87 Issue 3 Pages 035418-8
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract (La2/3Ca1/3MnO3)n/(BaTiO3)m (LCMOn/BTOm) superlattices on MgO and SrTiO3 substrates with different layer thicknesses (n = 10, 38, 40 and m = 5, 18, 20) have been grown by metal organic aerosol deposition (MAD) and have been fully characterized down to the atomic scale to study the interface characteristics. Scanning transmission electron microscopy combined with spatially resolved electron energy-loss spectroscopy provides clear evidence for the existence of atomically sharp interfaces in MAD grown films, which exhibit epitaxial growth conditions, a uniform normal strain, and a fully oxidized state. Below a critical layer thickness the LCMO structure is found to change from the bulk Pnma symmetry to a pseudocubic R3̅ c symmetry. An atomically flat interface reconstruction consisting of a single Ca-rich atomic layer is observed on the compressively strained BTO on LCMO interface, which is thought to partially neutralize the total charge from the alternating polar atomic layers in LCMO as well as relieving strain at the interface. No interface reconstruction is observed at the tensile strained LCMO on BTO interface.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000313940400008 Publication Date 2013-01-23
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 FWO; Hercules; Countatoms Approved Most recent IF: 3.836; 2013 IF: 3.664
Call Number UA @ lucian @ c:irua:106180 Serial 3245
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Author Tzedaki, G.; M.; Turner, S.; Godet, S.; De Graeve, I.; Kernig, B.; Hasenclever, J.; Terryn, H.
Title Structure and formation mechanism of rolled-in oxide areas on aluminum lithographic printing sheets Type A1 Journal article
Year (up) 2013 Publication Scripta materialia Abbreviated Journal Scripta Mater
Volume 68 Issue 5 Pages 233-236
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract The subsurface area introduced during rolling on the 1100 aluminum alloy series alters its surface properties, which makes it more susceptible to corrosion. A combination of different transmission electron microscopy techniques is employed to observe the orientation of small grain structures and the distribution elements in the subsurface layer. This approach provided valuable insight into the formation mechanism of the layer and the phenomena taking place during rolling.
Address
Corporate Author Thesis
Publisher Place of Publication Oxford Editor
Language Wos 000314012000003 Publication Date 2012-10-23
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1359-6462; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.747 Times cited 6 Open Access
Notes Fwo Approved Most recent IF: 3.747; 2013 IF: 2.968
Call Number UA @ lucian @ c:irua:105288 Serial 3277
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Author Batuk, M.; Tyablikov, O.A.; Tsirlin, A.A.; Kazakov, S.M.; Rozova, M.G.; Pokholok, K.V.; Filimonov, D.S.; Antipov, E.V.; Abakumov, A.M.; Hadermann, J.
Title Structure and magnetic properties of a new anion-deficient perovskite Pb2Ba2BiFe4ScO13 with crystallographic shear structure Type A1 Journal article
Year (up) 2013 Publication Materials research bulletin Abbreviated Journal Mater Res Bull
Volume 48 Issue 9 Pages 3459-3465
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Pb2Ba2BiFe4ScO13, a new n = 5 member of the oxygen-deficient perovskite-based A(n)B(n)O(3n-2) homologous series, was synthesized using a solid-state method. The crystal structure of Pb2Ba2BiFe4ScO13 was investigated by a combination of synchrotron X-ray powder diffraction, electron diffraction, high-angle annular dark-field scanning transmission electron microscopy and Mossbauer spectroscopy. At 900 K, it crystallizes in the Ammm space group with the unit cell parameters a = 5.8459(1) angstrom, b = 4.0426(1) angstrom, and c=27.3435(1) angstrom. In the Pb2Ba2BiFe4ScO13 structure, quasi-two-dimensional perovskite blocks are periodically interleaved with 1/2[1 1 0] ((1) over bar 0 1)(p) crystallographic shear (CS) planes. At the CS planes, the corner-sharing FeO6 octahedra are transformed into chains of edge-sharing FeO5 distorted tetragonal pyramids. B-positions of the perovskite blocks between the CS planes are jointly occupied by Fe3+ and Sc3+. The chains of the FeO5 pyramids and (Fe,Sc)O-6 octahedra delimit six-sided tunnels that are occupied by double columns of cations with a lone electron pair (Pb2+). The remaining A-cations (Bi3+, Ba2+) occupy positions in the perovskite block. According to the magnetic susceptibility measurements, Pb2Ba2BiFe4ScO13 is antiferromagnetically ordered below T-N approximate to 350 K. (C) 2013 Elsevier Ltd. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000322354000076 Publication Date 2013-05-17
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0025-5408; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.446 Times cited 2 Open Access
Notes Approved Most recent IF: 2.446; 2013 IF: 1.968
Call Number UA @ lucian @ c:irua:109756 Serial 3282
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Author Berdiyorov, G.R.; Savel'ev, S.E.; Milošević, M.V.; Kusmartsev, F.V.; Peeters, F.M.
Title Synchronized dynamics of Josephson vortices in artificial stacks of SNS Josephson junctions under both dc and ac bias currents Type A1 Journal article
Year (up) 2013 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 87 Issue 18 Pages 184510-184519
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Nonlinear dynamics of Josephson vortices (fluxons) in artificial stacks of superconducting-normal-superconducting Josephson junctions under simultaneously applied time-periodic ac and constant biasing dc currents is studied using the time dependent Ginzburg-Landau formalism with a Lawrence-Doniach extension. At zero external magnetic field and dc biasing current the resistive state of the system is characterized by periodic nucleation and annihilation of fluxon-antifluxon pairs, relative positions of which are determined by the state of neighboring junctions. Due to the mutual repulsive interaction, fluxons in different junctions move out of phase. Their collective motion can be synchronized by adding a small ac component to the biasing dc current. Coherent motion of fluxons is observed for a broad frequency range of the applied drive. In the coherent state the maximal output voltage, which is proportional to the number of junctions in the stack, is observed near the characteristic frequency of the system determined by the crossing of the fluxons across the sample. However, in this frequency range the dynamically synchronized state has an alternative-a less ordered state with smaller amplitude of the output voltage. Collective behavior of the junctions is strongly affected by the sloped sidewalls of the stack. Synchronization is observed only for weakly trapezoidal cross sections, whereas irregular motion of fluxons is observed for larger slopes of the sample edge.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000319653400007 Publication Date 2013-05-28
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 supported by the Flemish Science Foundation (FWO-VI) and by EU Marie Curie (Project No. 253057). ; Approved Most recent IF: 3.836; 2013 IF: 3.664
Call Number UA @ lucian @ c:irua:109643 Serial 3406
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Author Retuerto, M.; Emge, T.; Hadermann, J.; Stephens, P.W.; Li, M.R.; Yin, Z.P.; Croft, M.; Ignatov, A.; Zhang, S.J.; Yuan, Z.; Jin, C.; Simonson, J.W.; Aronson, M.C.; Pan, A.; Basov, D.N.; Kotliar, G.; Greenblatt, M.;
Title Synthesis and properties of charge-ordered thallium halide perovskites, CsTl0.5+Tl0.53+X3 (X = F or Cl) : theoretical precursors for superconductivity? Type A1 Journal article
Year (up) 2013 Publication Chemistry of materials Abbreviated Journal Chem Mater
Volume 25 Issue 20 Pages 4071-4079
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Recently, CsTlCl3 and CsTlF3 perovskites were theoretically predicted to be potential superconductors if they were optimally doped. The syntheses of these two compounds together with a complete characterization of the samples are reported. CsTlCl3 was obtained as orange crystals in two different polymorphs: a tetragonal phase (I4/m) and a cubic phase (Fm (3) over barm). CsTlF3 was formed as a light brown powder, and also as a double cubic perovskite (Fm (3) over barm). In all three CsTlX3 phases, Tl+ and Tl3+ were located in two different crystallographic positions that accommodate their different bond lengths. In CsTlCl3, some Tl vacancies were found in the Tl+ position. The charge ordering between Tl+ and Tl3+ was confirmed by X-ray absorption and Raman spectroscopy. The Raman spectroscopy of CsTlCl3 at high pressure (58 GPa) did not indicate any phase transition to a possible single Tl2+ state. However, the highly insulating material became less resistive with an increasing high pressure, while it underwent a change in its optical properties, from transparent to deeply opaque red, indicative of a decrease in the magnitude of the band gap. The theoretical design and experimental validation of the existence of CsTlF3 and CsTlCl3 cubic perovskites are the necessary first steps in confirming the theoretical prediction of superconductivity in these materials.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000326209200017 Publication Date 2013-09-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0897-4756;1520-5002; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 9.466 Times cited 28 Open Access
Notes Approved Most recent IF: 9.466; 2013 IF: 8.535
Call Number UA @ lucian @ c:irua:112248 Serial 3434
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Author Li, M.R.; Retuerto, M.; Bok Go, Y.; Emge, T.J.; Croft, M.; Ignatov, A.; Ramanujachary, K.V.; Dachraoui, W.; Hadermann, J.; Tang, M.B.; Zhao, J.T.; Greenblatt, M.;
Title Synthesis, crystal structure, and properties of KSbO3-type Bi3Mn1.9Te1.1O11 Type A1 Journal article
Year (up) 2013 Publication Journal of solid state chemistry Abbreviated Journal J Solid State Chem
Volume 197 Issue Pages 543-549
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Single crystals of Bi3Mn1.9Te1.1O11 were prepared from NaCl+KCl flux. This compound adopts KSbO3-type crystal structure as evidenced by electron and single crystal X-ray diffraction analysis. The three-dimensional channel structure is formed by corner-sharing octahedral (Mn0.63Te0.37)2O10 dimers and two identical (Bi1)4(Bi2)2 interpenetrating lattices. The intra-dimer Mn/TeMn/Te distances in Bi3Mn1.9Te1.1O11 are short and are consistent with weak metalmetal interactions. The mixed oxidation state of manganese and the edge-sharing octahedral features are confirmed by X-ray near edge absorption spectroscopy measurements, which indicate Bi3(MnIII1.1MnIV0.8)TeVI1.1O11 with 57.7% Mn3+ and 42.3% Mn4+. The partial substitution of Te for Mn perturbs long-range magnetic interactions, thereby destroying the ferromagnetic ordering found in Bi3Mn3O11 (TC=150 K).
Address
Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos 000312281000076 Publication Date 2012-07-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-4596; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.299 Times cited 13 Open Access
Notes Approved Most recent IF: 2.299; 2013 IF: 2.200
Call Number UA @ lucian @ c:irua:101779 Serial 3452
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Author Pietra, F.; van Dijk-Moes, R.J.A.; Ke, X.; Bals, S.; Van Tendeloo, G.; de Mello Donega, C.; Vanmaekelbergh, D.
Title Synthesis of highly luminescent silica-coated CdSe/CdS nanorods Type A1 Journal article
Year (up) 2013 Publication Chemistry of materials Abbreviated Journal Chem Mater
Volume 25 Issue 17 Pages 3427-3434
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract CdSe(core)/CdS(shell) nanorods (NRs) have been extensively investigated for their unique optical properties, such as high photoluminescence (PL) quantum efficiency (QE) and polarized light emission. The incorporation of these NRs in silica (SiO2) is of high interest, since this renders them processable in polar solvents while increasing their photochemical stability, which would be beneficial for their application in LEDs and as biolabels. We report the synthesis of highly luminescent silica-coated CdSe/CdS NRs, by using the reverse micelle method. The mechanism for the encapsulation of the NRs in silica is unravelled and shown to be strongly influenced by the NR shape and its asymmetry. This is attributed to both the different morphology and the different crystallographic nature of the facets terminating the opposite tips of the NRs. These results lead to the formation of a novel class of NR architectures, whose symmetry can be controlled by tuning the degree of coverage of the silica shell. Interestingly, the encapsulation of the NRs in silica leads to a remarkable increase in their photostability, while preserving their optical properties.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000330097900004 Publication Date 2013-08-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0897-4756;1520-5002; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 9.466 Times cited 46 Open Access
Notes 262348 ESMI; 246791 COUNTATOMS; Hercules Approved Most recent IF: 9.466; 2013 IF: 8.535
Call Number UA @ lucian @ c:irua:110037 Serial 3456
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Author Sree, S.P.; Dendooven, J.; Masschaele, K.; Hamed, H.M.; Deng, S.; Bals, S.; Detavernier, C.; Martens, J.A.
Title Synthesis of uniformly dispersed anatase nanoparticles inside mesoporous silica thin films via controlled breakup and crystallization of amorphous TiO2 deposited using atomic layer deposition Type A1 Journal article
Year (up) 2013 Publication Nanoscale Abbreviated Journal Nanoscale
Volume 5 Issue 11 Pages 5001-5008
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Amorphous titanium dioxide was introduced into the pores of mesoporous silica thin films with 75% porosity and 12 nm average pore diameter via Atomic Layer Deposition (ALD) using alternating pulses of tetrakis(dimethylamino)titanium and water. Calcination provoked fragmentation of the deposited amorphous TiO2 phase and its crystallization into anatase nanoparticles inside the nanoporous film. The narrow particle size distribution of 4 ± 2 nm and the uniform dispersion of the particles over the mesoporous silica support were uniquely revealed using electron tomography. These anatase nanoparticle bearing films showed photocatalytic activity in methylene blue degradation. This new synthesis procedure of the anatase nanophase in mesoporous silica films using ALD is a convenient fabrication method of photocatalytic coatings amenable to application on very small as well as very large surfaces
Address
Corporate Author Thesis
Publisher Place of Publication Cambridge Editor
Language Wos 000319008700056 Publication Date 2013-04-09
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2040-3364;2040-3372; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 7.367 Times cited 22 Open Access
Notes Fwo; Iap-Pai; Erc Approved Most recent IF: 7.367; 2013 IF: 6.739
Call Number UA @ lucian @ c:irua:108774 Serial 3460
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Author Kirsanova, M.A.; Mori, T.; Maruyama, S.; Matveeva; Batuk, D.; Abakumov, A.M.; Gerasimenko, A.V.; Olenev, A.V.; Grin, Y.; Shevelkov, A.V.
Title Synthesis, structure, and transport properties of type-I derived clathrate Ge46-xPxSe8-y (x=15.4(1); y=0-2.65) with diverse host-guest bonding Type A1 Journal article
Year (up) 2013 Publication Inorganic chemistry Abbreviated Journal Inorg Chem
Volume 52 Issue 2 Pages 577-588
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract A first clathrate compound with selenium guest atoms, [Ge46-xPx]Se8-y square(y) (x = 15.4(1); y = 0-2.65; square denotes a vacancy), was synthesized as a single-phase and structurally characterized. It crystallizes in the space group Fm (3) over bar with the unit cell parameter a varying from 20.310(2) to 20.406(2) angstrom and corresponding to a 2 x 2 x 2 supercell of a usual clathrate-I structure. The superstructure is formed due to the symmetrical arrangement of the three-bonded framework atoms appearing as a result of the framework transformation of the parent clathrate-I structure. Selenium guest atoms occupy two types of polyhedral cages inside the positively charged framework; all selenium atoms in the larger cages form a single covalent bond with the framework atoms, relating the title compounds to a scanty family of semiclathrates. According to the measurements of electrical resistivity and Seebeck coefficient, [Ge46-xPx]Se8-y square(y) is an n-type semiconductor with E-g = 0.41 eV for x = 15.4(1) and y = 0; it demonstrates the maximal thermoelectric power factor of 2.3 x 10(-5) W K-2 m(-1) at 660 K.
Address
Corporate Author Thesis
Publisher Place of Publication Easton, Pa Editor
Language Wos 000314007500010 Publication Date 2012-12-31
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0020-1669;1520-510X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.857 Times cited 14 Open Access
Notes Approved Most recent IF: 4.857; 2013 IF: 4.794
Call Number UA @ lucian @ c:irua:107689 Serial 3463
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Author Groeneveld, E.; Witteman, L.; Lefferts, M.; Ke, X.; Bals, S.; Van Tendeloo, G.; de Mello Donega, C.
Title Tailoring ZnSe-CdSe colloidal quantum dots via cation exchange : from core/shell to alloy nanocrystals Type A1 Journal article
Year (up) 2013 Publication ACS nano Abbreviated Journal Acs Nano
Volume 7 Issue 9 Pages 7913-7930
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract We report a study of Zn2+ by Cd2+ cation exchange (CE) in colloidal ZnSe nanocrystals (NCs). Our results reveal that CE in ZnSe NCs is a thermally activated isotropic process. The CE efficiency (i.e., fraction of Cd2+ ions originally in solution, Cdsol, that is incorporated in the ZnSe NC) increases with temperature and depends also on the Cdsol/ZnSe ratio. Interestingly, the reaction temperature can be used as a sensitive parameter to tailor both the composition and the elemental distribution profile of the product (Zn,Cd)Se NCs. At 150 °C ZnSe/CdSe core/shell hetero-NCs (HNCs) are obtained, while higher temperatures (200 and 220 °C) produce (Zn1xCdx)Se gradient alloy NCs, with increasingly smoother gradients as the temperature increases, until homogeneous alloy NCs are obtained at T ≥ 240 °C. Remarkably, sequential heating (150 °C followed by 220 °C) leads to ZnSe/CdSe core/shell HNCs with thicker shells, rather than (Zn1xCdx)Se gradient alloy NCs. Thermal treatment at 250 °C converts the ZnSe/CdSe core/shell HNCs into (Zn1xCdx)Se homogeneous alloy NCs, while preserving the NC shape. A mechanism for the cation exchange in ZnSe NCs is proposed, in which fast CE takes place at the NC surface, and is followed by relatively slower thermally activated solid-state cation diffusion, which is mediated by Frenkel defects. The findings presented here demonstrate that cation exchange in colloidal ZnSe NCs provides a very sensitive tool to tailor the nature and localization regime of the electron and hole wave functions and the optoelectronic properties of colloidal ZnSeCdSe NCs.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000330016900051 Publication Date 2013-08-13
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 153 Open Access
Notes 262348 Esmi; 246791 Countatoms Approved Most recent IF: 13.942; 2013 IF: 12.033
Call Number UA @ lucian @ c:irua:110038 Serial 3469
Permanent link to this record
 
 
Author Idrissi, H.; Renard, K.; Schryvers, D.; Jacques, P.J.
Title TEM investigation of the formation mechanism of deformation twins in Fe-Mn-Si-Al TWIP steels Type A1 Journal article
Year (up) 2013 Publication Philosophical magazine Abbreviated Journal Philos Mag
Volume 93 Issue 35 Pages 4378-4391
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract The microstructure of a Fe-Mn-Si-Al twinning-induced plasticity (TWIP) steel exhibiting remarkable work hardening rate under uniaxial tensile deformation was investigated using transmission electron microscopy to uncover the mechanism(s) controlling the nucleation and growth of the mechanically induced twins. The results show that the stair-rod cross-slip deviation mechanism is necessary for the formation of the twins, while large extrinsic stacking faults homogenously distributed within the grains could act as preferential sources for the activation of the deviation process. The influence of such features on the thickness and strength of the twins and the resulting mechanical behaviour is discussed and compared to similar works recently performed on Fe-Mn-C TWIP steels.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000327478300005 Publication Date 2013-09-12
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1478-6435;1478-6443; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.505 Times cited 15 Open Access
Notes Approved Most recent IF: 1.505; 2013 IF: 1.427
Call Number UA @ lucian @ c:irua:112815 Serial 3478
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Author Somers, W.; Bogaerts, A.; van Duin, A.C.T.; Huygh, S.; Bal, K.M.; Neyts, E.C.
Title Temperature influence on the reactivity of plasma species on a nickel catalyst surface : an atomic scale study Type A1 Journal article
Year (up) 2013 Publication Catalysis today Abbreviated Journal Catal Today
Volume 211 Issue Pages 131-136
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract In recent years, the potential use of hydrogen as a clean energy source has gained considerable attention. Especially H2 formation by Ni-catalyzed reforming of methane at elevated temperatures is an attractive process. However, a more fundamental knowledge at the atomic level is needed for a full comprehension of the reactions at the catalyst surface. In this contribution, we therefore investigate the H2 formation after CHx impacts on a Ni(1 1 1) surface in the temperature range 4001600 K, by means of reactive molecular dynamics (MD) simulations using the ReaxFF potential. While some H2 formation is already observed at the lower temperatures, substantial H2 formation is only obtained at elevated temperatures of 1400 K and above. At 1600 K, the H2 molecules are even the most frequently formed species. In direct correlation with the increasing dehydrogenation at elevated temperatures, an increased surface-to-subsurface C-diffusivity is observed as well. This study highlights the major importance of the temperature on the H2 formation.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000320697800020 Publication Date 2013-03-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0920-5861; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.636 Times cited 27 Open Access
Notes Approved Most recent IF: 4.636; 2013 IF: 3.309
Call Number UA @ lucian @ c:irua:108675 Serial 3500
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Author Berdonosov, P.S.; Akselrud, L.; Prots, Y.; Abakumov, A.M.; Smet, P.F.; Poelman, D.; Van Tendeloo, G.; Dolgikh, V.A.
Title Cs7Nd11(SeO3)12Cl16 : first noncentrosymmetric structure among alkaline-metal lanthanide selenite halides Type A1 Journal article
Year (up) 2013 Publication Inorganic chemistry Abbreviated Journal Inorg Chem
Volume 52 Issue 7 Pages 3611-3619
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Cs7Nd11(SeO3)(12)Cl-16, the complex selenite chloride of cesium and neodymium, was synthesized in the NdOCl-SeO2-CsCl system. The compound has been characterized using single-crystal X-ray diffraction, electron diffraction, transmission electron microscopy, luminescence spectroscopy, and second-harmonic-generation techniques. Cs7Nd11(SeO3)(12)Cl-16 crystallizes in an orthorhombic unit cell with a = 15.911(1) angstrom, b = 15.951(1) angstrom, and c = 25.860(1) angstrom and a noncentrosymmetric space group Pna2(1) (No. 33). The crystal structure of Cs7Nd11(SeO3)(12)Cl-16 can be represented as a stacking of Cs7Nd11(SeO3)(12) lamellas and CsCl-like layers. Because of the layered nature of the Cs7Nd11(SeO3)(12)Cl-16 structure, it features numerous planar defects originating from occasionally missing the CsCl-like layer and violating the perfect stacking of the Cs7Nd11(SeO3)(12)Cl-16 lamellas. Cs7Nd11(SeO3)(12)Cl-16 represents the first example of a noncentrosymmetric structure among alkaline-metal lanthanide selenite halides. Cs7Nd11(SeO3)(12)Cl-16 demonstrates luminescence emission in the near-IR region with reduced efficiency due to a high concentration of Nd3+ ions causing nonradiative cross-relaxation.
Address
Corporate Author Thesis
Publisher Place of Publication Easton, Pa Editor
Language Wos 000317094300022 Publication Date 2013-03-11
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0020-1669;1520-510X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.857 Times cited 10 Open Access
Notes Approved Most recent IF: 4.857; 2013 IF: 4.794
Call Number UA @ lucian @ c:irua:108482 Serial 3524
Permanent link to this record
 
 
Author Tyutyunnik, A.P.; Slobodin, B.V.; Samigullina, R.F.; Verberck, B.; Tarakina, N.V.
Title K2CaV2O7 : a pyrovanadate with a new layered type of structure in the A2BV2O7 family Type A1 Journal article
Year (up) 2013 Publication Journal of the Chemical Society : Dalton transactions Abbreviated Journal Dalton T
Volume 42 Issue 4 Pages 1057-1064
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The crystal structure of K2CaV2O7 prepared by a conventional solid-state reaction has been solved by a direct method and refined using Rietveld full profile fitting based on X-ray powder diffraction data. This compound crystallises in the triclinic space group (P (1) over bar, Z = 2) with unit cell constants a = 7.1577(1) angstrom, b = 10.5104(2) angstrom, c = 5.8187(1) angstrom, alpha = 106.3368(9)degrees, beta = 106.235(1)degrees, gamma = 71.1375(9)degrees. The structure can be described as infinite undulating CaV2O72- layers parallel to the ac plane, which consist of pairs of edge-sharing CaO6 octahedra connected to each other through V2O7 pyrogroups. The potassium atoms are positioned in two sites between the layers, with a distorted IX-fold coordination of oxygen atoms. The chemical composition obtained from the structural solution was confirmed by energy-dispersive X-ray analysis. The stability of compounds in the family of alkali metal calcium pyrovanadates is discussed based on an analysis of the correlation between anion and cation sizes and theoretical first-principles calculations.
Address
Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos 000312659200030 Publication Date 2012-10-04
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1477-9226;1477-9234; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.029 Times cited 3 Open Access
Notes ; N.V.T. acknowledges funding by the Bavarian Ministry of Sciences, Research and the Arts. B. V. was financially supported by the Flemish Science Foundation (FWO-Vlaanderen). ; Approved Most recent IF: 4.029; 2013 IF: 4.097
Call Number UA @ lucian @ c:irua:105945 Serial 3536
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Author Damm, H.; Kelchtermans, A.; Bertha, A.; Van den Broeck, F.; Elen, K.; Martins, J.C.; Carleer, R.; D'Haen, J.; De Dobbelaere, C.; Hadermann, J.; Hardy, A.; Van Bael, M.K.;
Title Thermal decomposition synthesis of Al-doped ZnO nanoparticles : an in-depth study Type A1 Journal article
Year (up) 2013 Publication RSC advances Abbreviated Journal Rsc Adv
Volume 3 Issue 45 Pages 23745-23754
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Al-doped ZnO nanoparticles are synthesized by means of a heating up solution based thermal decomposition method. The synthesis involves a reaction of zinc acetylacetonate hydrate, aluminium acetylacetonate and 1,2-hexadecanediol in the presence of oleic acid and oleyl amine. A proposed reaction mechanism from reagents to monomers is corroborated by analysis of the evolving gases using headspace GC-MS analysis. The Al-doped ZnO nanoparticles synthesized are dynamically stabilized by adsorbed oleate ions, after deprotonation of oleic acid by oleyl amine, as was found by NOESY proton NMR and complementary FTIR spectroscopy. Precession electron diffraction shows a simultaneous increase in lattice parameters with Al concentration. This, together with HAADF-STEM and EDX maps, indicates the incorporation of Al into the ZnO nanoparticles. By the combination of complementary characterization methods during all stages of the synthesis, it is concluded that Al is incorporated into the ZnO wurtzite lattice as a dopant.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000326395800139 Publication Date 2013-10-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2046-2069; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.108 Times cited 10 Open Access
Notes Approved Most recent IF: 3.108; 2013 IF: 3.708
Call Number UA @ lucian @ c:irua:112753 Serial 3627
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