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“Symmetry-adapted rotator functions for molecules in cylindrical confinement”. Verberck B, International journal of molecular sciences 12, 317 (2011). http://doi.org/10.3390/ijms12010317
Abstract: We present a general description of the formalism of symmetry-adapted rotator functions (SARFs) for molecules in cylindrical confinement. Molecules are considered as clusters of interaction centers (ICs), can have any symmetry, and can display different types of ICs. Cylindrical confinement can be realized by encapsulation in a carbon nanotube (CNT). The potential energy of a molecule surrounded by a CNT can be calculated by evaluating a limited number of terms of an expansion into SARFs, which offers a significant reduction of the computation time. Optimal molecular orientations can be deduced from the resulting potential energy landscape. Examples, including the case of a molecule with cubic symmetry inside a CNT, are discussed.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.226
Times cited: 1
DOI: 10.3390/ijms12010317
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“Synthesis and catalytic activity of Ti-MCM-41 nanoparticles with highly active titanium sites”. Lin K, Pescarmona PP, Vandepitte H, Liang D, Van Tendeloo G, Jacobs PA, Journal of catalysis 254, 64 (2008). http://doi.org/10.1016/j.jcat.2007.11.017
Abstract: Ti-MCM-41 nanoparticles 80-160 nm in diameter (Ti-MCM-41 NP) were successfully prepared by a dilute solution route in sodium hydroxide medium at ambient temperature. Ti-MCM-41 NP were characterized by X-ray diffraction, nitrogen adsorption/desorption isotherms, SEM, TEM. FT-IR, and UV-vis spectroscopy. The characterization results showed the existence of highly ordered hexagonal mesoporous structure and tetrahedral Ti species in Ti-MCM-41 NP. In the epoxidation of cyclohexene with aqueous H2O2, Ti-MCM-41 NP displayed higher conversion and initial reaction rate than a Ti-MCM-41 sample with normal particle size (Ti-MCM-41 LP). Diffusion of the reactants was accelerated and the accessibility to the catalytic Ti species was enhanced in the shorter channels in Ti-MCM-41 NP samples. Ti-MCM-41 NP showed much higher selectivity for cyclohexene oxide compared with Ti-MCM-41 LP, suggesting reduced hydrolysis of cyclohexene oxide with water in the former case. The increased selectivity for cyclohexene oxide can be attributed to the lower concentration of residual surface silanols in Ti-MCM-41 NP and the shorter residence time of epoxide in the shorter mesoporous channels. Ti-MCM-41 NP also appears to be a suitable catalyst in the epoxidation of a bulky substrate, like cholesterol, with tert-butyl hydroperoxide. (c) 2007 Elsevier Inc. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.844
Times cited: 52
DOI: 10.1016/j.jcat.2007.11.017
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“Synthesis and crystal structure of novel layered manganese oxide Ca2MnGaO5+\delta”. Abakumov AM, Rozova MG, Pavlyuk BP, Lobanov MV, Antipov EV, Lebedev OI, Van Tendeloo G, Sheptyakov DV, Balagurov AM, Bourée F, Journal of solid state chemistry 158, 100 (2001). http://doi.org/10.1006/jssc.2000.9105
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.299
Times cited: 48
DOI: 10.1006/jssc.2000.9105
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“Synthesis and crystal structure of Sr2ScBiO6”. Kazin PE, Abakumov AM, Zaytsev DD, Tretyakov YD, Khasanova NR, Van Tendeloo G, Jansen M, Journal of solid state chemistry 162, 142 (2001). http://doi.org/10.1006/jssc.2001.9375
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.299
Times cited: 3
DOI: 10.1006/jssc.2001.9375
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“Synthesis and structure determination of ferromagnetic semiconductors LaAMnSnO6(A = Sr, Ba)”. Yang T, Perkisas T, Hadermann J, Croft M, Ignatov A, Van Tendeloo G, Greenblatt M, Journal of materials chemistry 21, 199 (2011). http://doi.org/10.1039/c0jm02614j
Abstract: LaAMnSnO(6) (A = Sr, Ba) have been synthesized by high temperature solid-state reactions under dynamic 1% H(2)/Ar flow. Rietveld refinements on room temperature powder X-ray diffraction data indicate that LaSrMnSnO(6) crystallizes in the GdFeO(3)-structure, with space group Pnma and, combined with transmission electron microscopy, LaBaMnSnO(6) in Imma. Both space groups are common in disordered double-perovskites. The Mn(3+) and Sn(4+) ions whose valence states were confirmed by X-ray absorption spectroscopy, are completely disordered over the B-sites and the BO(6) octahedra are slightly distorted. LaAMnSnO(6) are ferromagnetic semiconductors with a T(C) = 83 K for the Sr- and 66 K for the Ba-compound. The title compounds, together with the previously reported LaCaMnSnO(6) provide an interesting example of progression from Pnma to Imma as the tolerance factor increases. An analysis of the relationship between space group and tolerance factor for the series LaAMnMO(6) (A = Ca, Sr, Ba; M = Sn, Ru) provides a better understanding of the symmetry determination for double perovskites.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 3
DOI: 10.1039/c0jm02614j
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“Systematic errors in 14-MeV neutron activation analysis for oxygen : part 2 : a general standardization method for the determination of oxygen”. Vandecasteele C, van Grieken R, Gijbels R, Speecke A, Analytica chimica acta 65, 1 (1973). http://doi.org/10.1016/S0003-2670(01)80158-6
Abstract: A general standardization method is described for the determination of oxygen in solid samples via the 16O(n,p)16N reaction. Two systems of flux monitoring are considered: the sample versus standard comparator method and BF3 monitoring. The average flux in sample and standard, fast neutron shielding, fast neutron scattering, absorption of fast neutrons, absorption of 16N γ-rays and counting efficiency of sample and standard are considered. The influence of the target diameter on the obtained correction factors has also been studied. Total achievable accuracy is believed to be about 1%.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT); AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 4.513
Times cited: 12
DOI: 10.1016/S0003-2670(01)80158-6
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“TEM study of laser induced phase transition in iron thin films”. Teodorescu VS, Nistor LC, van Landuyt J, Dinescu M, Materials research bulletin 29, 63 (1994). http://doi.org/10.1016/0025-5408(94)90106-6
Abstract: Laser induced phase transition from b.c.c.(alpha) to f.c.c.(gamma) iron thin films is studied by high resolution TEM. The iron film has been covered on both sides with carbon layers to protect it against oxidation. Single pulse, tau FWHM = 20ns KrF (lambda = 248nm) excimer laser irradiation was performed in air with the film on the substrate. The laser pulse acts like a heat pulse followed by a rapid quenching revealing sequential aspects of the phase transition process. The presence of a fine mixture of the alpha + gamma phases between the alpha and gamma regions of the film has been interpreted as an incomplet transformation. The results are explained by assuming that the transformation took place via a phonon drag mechanism.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.288
Times cited: 2
DOI: 10.1016/0025-5408(94)90106-6
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“TEM study of YBa2Cu3O7-x thin films with Zn and Fe”. Verbist K, Van Tendeloo G, Ye M, Mehbod M, Deltour R, Physica: C : superconductivity 235, 663 (1994). http://doi.org/10.1016/0921-4534(94)91555-5
Abstract: Analytical and high resolution electron microscopy have been used to study the effect of Zn- and Fe-doping on the micro structure of [001] YBa2Cu3O7-x thin films on [001] MgO substrates grown by magnetron sputtering. Special attention was paid to the presence of second phase inclusions and surface outgrowths such as CuO, Y2Ba1Cu1O5-x, Y2O3 in order to establish a relationship with the critical current density.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 0.942
DOI: 10.1016/0921-4534(94)91555-5
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“Temperature and magnetic field dependence of the voltagein GaAs films with superconducting Ga grains”. Willems BL, Taylor DMJ, Fritzsche J, Malfait M, Vanacken J, Moshchalkov VV, Montoya E, Van Tendeloo G, European physical journal : B : condensed matter and complex systems 66, 25 (2008). http://doi.org/10.1140/epjb/e2008-00386-3
Abstract: We have studied granular films consisting of nanoscale Ga droplets formed on GaAs films via a method of vacuum annealing to promote As evaporation. For temperatures and magnetic fields below the bulk Ga critical parameters, the samples are very sensitive towards external microwave radiation when two point voltage measurements are performed. Together with the observation of an oscillating magnetic field dependence of the voltage, a scenario in which the samples consist of Josephson-coupled loops seems to be the most likely one for explaining the obtained results.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.461
DOI: 10.1140/epjb/e2008-00386-3
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“Fe3O4/ZnO : a high-quality magnetic oxide-semiconductor heterostructure by reactive deposition”. Paul M, Kufer D, Müller A, Brück S, Goering E, Kamp M, Verbeeck J, Tian H, Van Tendeloo G, Ingle NJC, Sing M, Claessen R, Applied physics letters 98, 012512 (2011). http://doi.org/10.1063/1.3540653
Abstract: We demonstrate the epitaxial growth of Fe<sub>3</sub>O<sub>4</sub> films on ZnO by a simple reactive deposition procedure using molecular oxygen as an oxidizing agent. X-ray photoelectron spectroscopy results evidence that the iron-oxide surface is nearly stoichiometric magnetite. X-ray diffraction results indicate monocrystalline epitaxy and almost complete structural relaxation. Scanning transmission electron micrographs reveal that the microstructure consists of domains which are separated by antiphase boundaries or twin boundaries. The magnetite films show rather slow magnetization behavior in comparison with bulk crystals probably due to reduced magnetization at antiphase boundaries in small applied fields.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.411
Times cited: 27
DOI: 10.1063/1.3540653
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“The ground states of the two-component order parameter superconductor”. Doria MM, de Romaguera ARC, Peeters FM, Europhysics letters 92, 17004 (2010). http://doi.org/10.1209/0295-5075/92/17004
Abstract: We show that in presence of an applied external field the two-component order parameter superconductor falls in two categories of ground states, namely, in the traditional Abrikosov ground state or in a new ground state fitted to describe a superconducting layer with texture, that is, patched regions separated by a phase difference of pi. The existence of these two kinds of ground states follows from the sole assumption that the total supercurrent is the sum of the two individual supercurrents and is independent of any consideration about the free energy expansion. Uniquely defined relations between the current density and the superfluid density hold for these two ground states, which also determine the magnetization in terms of average values of the order parameters. Because these ground-state conditions are also Bogomolny equations we construct the free energy for the two-component superconductor which admits the Bogomolny solution at a special coupling value. Copyright (C) EPLA, 2010
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.957
Times cited: 8
DOI: 10.1209/0295-5075/92/17004
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“The superconducting proximity effect in epitaxial Al/Pb nanocomposites”. Wang H, Picot T, Houben K, Moorkens T, Grigg J, Van Haesendonck C, Biermans E, Bals S, Brown SA, Vantomme A, Temst K, Van Bael MJ;, Superconductor science and technology 27, 015008 (2014). http://doi.org/10.1088/0953-2048/27/1/015008
Abstract: We have investigated the superconducting properties of Pb nanoparticles with a diameter ranging from 8 to 20 nm, synthesized by Pb+ ion implantation in a crystalline Al matrix. A detailed structural characterization of the nanocomposites reveals the highly epitaxial relation between the Al crystalline matrix and the Pb nanoparticles. The Al/Pb nanocomposites display a single superconducting transition, with the critical temperature T-c increasing with the Pb content. The dependence of T-c on the Pb/Al volume ratio was compared with theoretical models of the superconducting proximity effect based on the bulk properties of Al and Pb. A very good correspondence with the strong-coupling proximity effect model was found, with an electron-phonon coupling constant in the Pb nanoparticles slightly reduced compared to bulk Pb. Our result differs from other studies on Pb nanoparticle based proximity systems where weak-coupling models were found to better describe the T-c dependence. We infer that the high interface quality resulting from the ion implantation synthesis method is a determining factor for the superconducting properties. Critical field and critical current measurements support the high quality of the nanocomposite superconducting films.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.878
Times cited: 2
DOI: 10.1088/0953-2048/27/1/015008
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“Time dependent transport in 1D micro- and nanostructures: solving the Boltzmann and Wigner-Boltzmann equations”. Magnus W, Brosens F, Sorée B, Journal of physics : conference series 193, 012004 (2009). http://doi.org/10.1088/1742-6596/193/1/012004
Abstract: For many decades the Boltzmann distribution function has been used to calculate the non-equilibrium properties of mobile particles undergoing the combined action of various scattering mechanisms and externally applied force fields. When the latter give rise to the occurrence of inhomogeneous potential profiles across the region through which the particles are moving, the numerical solution of the Boltzmann equation becomes a highly complicated task. In this work we highlight a particular algorithm that can be used to solve the time dependent Boltzmann equation as well as its quantum mechanical extension, the WignerBoltzmann equation. As an illustration, we show the calculated distribution function describing electrons propagating under the action of both a uniform and a pronouncedly non-uniform electric field.
Keywords: A1 Journal article; Condensed Matter Theory (CMT); Theory of quantum systems and complex systems
Times cited: 2
DOI: 10.1088/1742-6596/193/1/012004
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“Trace-elemental anomalies in surface water near a small lead-zinc mineralization at Menez-Albot (Brittany, France)”. Vandelannoote R, Blommaert W, Sadurski A, Van 'T Dack L, Gijbels R, Van Grieken R, Bosch B, Leleu M, Rochon J, Sarcia C, Sureau JF;, Journal of geochemical exploration 20, 33 (1984). http://doi.org/10.1016/0375-6742(84)90088-8
Abstract: Sensitive multi-element analysis techniques were applied to water samples collected in the vicinity of a small Zn-Pb-Cu sulfide mineralization in the region of Menez-Albot (Finistère, France). The variation of the trace-element content along a local stream shows the presence of the mineralization, mainly through a simultaneous positive anomaly in solution for a group of about 10 elements (e.g. Ni, Cu, Zn, As, Sb) which are connected with this type of mineralization. The anomaly decreases steeply due to the influx of swamp water rich in Fe, Mn and organic matter. The precipitation barrier is reflected in the stream sediment composition. Contamination from fertilizers was observed in some samples.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT); AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 2.747
Times cited: 4
DOI: 10.1016/0375-6742(84)90088-8
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“Transformation of C70 peapods into double walled carbon nanotubes”. Launois P, Chorro M, Verberck B, Albouy P-A, Rouzière S, Colson D, Forget A, Noé, L, Kataura H, Monthioux M, Cambedouzou J, Carbon 48, 89 (2010). http://doi.org/10.1016/j.carbon.2009.08.035
Abstract: X-ray diffraction studies comparing the transformation of C(60) and C(70) peapods into double walled carbon nanotubes are presented. The structures of the as-formed DWCNTs are strikingly similar, showing that they are not dependent on the nature of the fullerene precursor. High temperature X-ray diffraction measurements of C(70) peapods below the coalescence temperature show that confined C(70) molecules in large tubes undergo an orientational. transition to free rotations. Fast re-orientations of C(70) molecules allow cyclo-addition between adjacent fullerenes to form, in good agreement with the mechanism of coalescence proposed in the literature for C(60) molecules. (C) 2009 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 6.337
Times cited: 27
DOI: 10.1016/j.carbon.2009.08.035
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“Transmission electron microscopy and structural phase transitions in anion-deficient perovskite-based oxides”. Hadermann J, Van Tendeloo G, Abakumov AM, Acta crystallographica: section A: foundations of crystallography 61, 77 (2005). http://doi.org/10.1107/S0108767304023013
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 5.725
Times cited: 18
DOI: 10.1107/S0108767304023013
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“Tunable diffusion of magnetic particles in a quasi-one-dimensional channel”. Lucena D, Ferreira WP, Munarin FF, Farias GA, Peeters FM, Physical review : E : statistical, nonlinear, and soft matter physics 87, 012307 (2013). http://doi.org/10.1103/PhysRevE.87.012307
Abstract: The diffusion of a system of ferromagnetic dipoles confined in a quasi-one-dimensional parabolic trap is studied using Brownian dynamics simulations. We show that the dynamics of the system is tunable by an in-plane external homogeneous magnetic field. For a strong applied magnetic field, we find that the mobility of the system, the exponent of diffusion, and the crossover time among different diffusion regimes can be tuned by the orientation of the magnetic field. For weak magnetic fields, the exponent of diffusion in the subdiffusive regime is independent of the orientation of the external field. DOI: 10.1103/PhysRevE.87.012307
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.366
Times cited: 11
DOI: 10.1103/PhysRevE.87.012307
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“Tunable double Dirac cone spectrum in bilayer \alpha-graphyne”. Leenaerts O, Partoens B, Peeters FM, Applied physics letters 103, 013105 (2013). http://doi.org/10.1063/1.4812977
Abstract: Monolayer alpha-graphyne was recently proposed as a new all-carbon material having an electronic spectrum consisting of Dirac cones. Based on a first-principles investigation of bilayer alpha-graphyne, we show that the electronic band structure is qualitatively different from its monolayer form and depends crucially on the stacking mode of the two layers. Two stable stacking modes are found: a configuration with a gapless parabolic band structure, similar to AB stacked bilayer graphene, and another one which exhibits a doubled Dirac-cone spectrum. The latter can be tuned by an electric field with a gap opening rate of 0.3 eA. (C) 2013 AIP Publishing LLC.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.411
Times cited: 58
DOI: 10.1063/1.4812977
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“Tunable exciton Aharonov-Bohm effect in a quantum ring”. Li B, Magnus W, Peeters FM, Journal of physics : conference series
T2 –, Proceedings of the 11th International Conference on Optics of Excitons in Confined Systems, September 7-11, 2009, Spain / Vina, L. [edit.], et al. [edit.] 210, 012030 (2010). http://doi.org/10.1088/1742-6596/210/1/012030
Abstract: We studied the optical Aharonov-Bohm effect for an exciton in a semiconductor quantum ring. A perpendicular electric field applied to a quantum ring with large height, is able to tune the exciton ground state energy such that it exhibits a weak observable Aharonov-Bohm oscillations. This Aharonov-Bohm effect is tunable in strength and period.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Times cited: 3
DOI: 10.1088/1742-6596/210/1/012030
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“Unraveling the deposition mechanism in a-C:H thin-film growth: a molecular-dynamics study for the reaction behavior of C3 and C3H radicals with a-C:H surfaces”. Neyts E, Bogaerts A, van de Sanden MCM, Journal of applied physics 99, 014902 (2006). http://doi.org/10.1063/1.2150149
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.068
Times cited: 25
DOI: 10.1063/1.2150149
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“Vibrational properties of silicene and germanene”. Scalise E, Houssa M, Pourtois G, van den Broek B, Afanas'ev V, Stesmans A, Nano Research 6, 19 (2013). http://doi.org/10.1007/s12274-012-0277-3
Abstract: The structural and vibrational properties of two-dimensional hexagonal silicon (silicene) and germanium (germanene) are investigated by means of first-principles calculations. It is predict that the silicene (germanene) structure with a small buckling of 0.44 (0.7 ) and bond lengths of 2.28 (2.44 ) is energetically the most favorable, and it does not exhibit imaginary phonon mode. The calculated non-resonance Raman spectra of silicene is characterized by a main peak at about 575 cm(-1), namely the G-like peak. For germanene, the highest peak is at about 290 cm(-1). Extensive calculations on armchair silicene nanoribbons and armchair germanene nanoribbons are also performed, with and without hydrogenation of the edges. The studies reveal other Raman peaks mainly distributed at lower frequencies than the G-like peak which could be attributed to the defects at the edges of the ribbons, thus not present in the Raman spectra of non-defective silicene and germanene. Particularly the Raman peak corresponding to the D mode is found to be located at around 515 cm(-1) for silicene and 270 cm(-1) for germanene. The calculated G-like and the D peaks are likely the fingerprints of the Raman spectra of the low-buckled structures of silicene and germanene.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 7.354
Times cited: 105
DOI: 10.1007/s12274-012-0277-3
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“Vortex-antivortex lattices in superconducting films with magnetic pinning arrays”. Milošević, MV, Peeters FM, Journal of low temperature physics 139, 257 (2005). http://doi.org/10.1007/s10909-005-3929-9
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.3
Times cited: 12
DOI: 10.1007/s10909-005-3929-9
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“Vortex configurations in mesoscopic superconducting triangles: finite-size and shape effects”. Zhao HJ, Misko VR, Peeters FM, Dubonos G, Oboznov V, Grigorieva IV, Europhysics letters 83, 17008 (2008). http://doi.org/10.1209/0295-5075/83/17008
Abstract: Triangular-shaped mesoscopic superconductors are consistent with the symmetry of the Abrikosov vortex lattice resulting in a high stability of vortex patterns for commensurate vorticities. However, for non-commensurate vorticities, vortex configurations in triangles are not compatible with the sample shape. Here we present the first direct observation of vortex configurations in ìm-sized niobium triangles using the Bitter decoration technique, and we analyze the vortex states in triangles by analytically solving the London equations and performing molecular-dynamics simulations. We found that filling rules with increasing vorticity can be formulated for triangles in a similar way as for mesoscopic disks where vortices form shells.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.957
Times cited: 29
DOI: 10.1209/0295-5075/83/17008
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“Vortex interaction enhanced saturation number and caging effect in a superconducting film with a honeycomb array of nanoscale holes”. Latimer ML, Berdiyorov GR, Xiao ZL, Kwok WK, Peeters FM, Physical review : B : condensed matter and materials physics 85, 012505 (2012). http://doi.org/10.1103/PhysRevB.85.012505
Abstract: The electrical transport properties of a MoGe thin film with a honeycomb array of nanoscale holes are investigated. The critical current of the system shows nonmatching anomalies as a function of applied magnetic field, enabling us to distinguish between multiquanta vortices trapped in the holes and interstitial vortices located between the holes. The number of vortices trapped in each hole is found to be larger than the saturation number predicted for an isolated hole and shows a nonlinear field dependence, leading to the caging effect as predicted from the Ginzburg-Landau (GL) theory. Our experimental results are supplemented by numerical simulations based on the GL theory.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 41
DOI: 10.1103/PhysRevB.85.012505
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“Proximity effect and Josephson current in clean strong/weak/strong superconducting trilayers”. Covaci L, Marsiglio F, Physical Review B 73, 014503 (2006). http://doi.org/10.1103/PhysRevB.73.014503
Abstract: Recent measurements of the Josephson critical current through LSCO/LCO/LSCO thin films showed an unusually large proximity effect. Using the Bogoliubov-de Gennes equations for a tight-binding Hamiltonian we describe the proximity effect in weak links between a superconductor with critical temperature T-c and one with critical temperature T-c('), where T-c > T-c('). The weak link (N-') is therefore a superconductor above its own critical temperature and the superconducting regions are considered to have either s-wave or d-wave symmetry. We note that the proximity effect is enhanced due to the presence of superconducting correlations in the weak link. The dc Josephson current is calculated, and we obtain a nonzero value for temperatures greater than T-c(') for sizes of the weak links that can be almost an order of magnitude greater than the conventional coherence length. Considering pockets of superconductivity in the N-' layer, we show that this can lead to an even larger effect on the Josephson critical current by effectively shortening the weak link.
Keywords: A1 Journal article
Impact Factor: 3.836
Times cited: 31
DOI: 10.1103/PhysRevB.73.014503
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“On improving accuracy of finite-element solutions of the effective-mass Schrodinger equation for interdiffused quantum wells and quantum wires”. Topalovic DB, Arsoski VV, Pavlovic S, Cukaric NA, Tadic MZ, Peeters FM, Communications in theoretical physics 65, 105 (2016)
Abstract: We use the Galerkin approach and the finite-element method to numerically solve the effective-mass Schrodinger equation. The accuracy of the solution is explored as it varies with the range of the numerical domain. The model potentials are those of interdiffused semiconductor quantum wells and axially symmetric quantum wires. Also, the model of a linear harmonic oscillator is considered for comparison reasons. It is demonstrated that the absolute error of the electron ground state energy level exhibits a minimum at a certain domain range, which is thus considered to be optimal. This range is found to depend on the number of mesh nodes N approximately as alpha(0) log(e)(alpha 1) (alpha N-2), where the values of the constants alpha(0), alpha(1), and alpha(2) are determined by fitting the numerical data. And the optimal range is found to be a weak function of the diffusion length. Moreover, it was demonstrated that a domain range adaptation to the optimal value leads to substantial improvement of accuracy of the solution of the Schrodinger equation.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 0.989
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“What modeling reveals about the properties of an inductively coupled plasma”. Bogaerts A, Aghaei M, Spectroscopy 31, 52 (2016)
Abstract: To get better performance from inductively coupled plasma (ICP)-based methods, it is informative to study the properties of the ICP under different conditions. Annemie Bogaerts and Maryam Aghaei at the University of Antwerp, Belgium, are using computational modeling to examine how various properties of the ICP, such as gas flow path lines and velocity, temperature changes, and ionization effects, are affected by numerous factors, such as the gas flow rates of injector and auxiliary gas, applied power, and even the very presence of a mass spectrometry (MS) sampler. They have also applied their models to study particle transport through the ICP. Using their developed model, it is now possible to predict optimum conditions for specific analyses. Bogaerts and Aghaei spoke to us about this work.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 0.466
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“Silver Ions Direct Twin-Plane Formation during the Overgrowth of Single-Crystal Gold Nanoparticles”. Grzelczak M, Sanchez-Iglesias A, Heidari H, Bals S, Pastoriza-Santos I, Perez-Juste J, Liz-Marzan LM, ACS Omega 1, 177 (2016). http://doi.org/10.1021/ACSOMEGA.6B00066
Abstract: It is commonly agreed that the crystalline structure of seeds dictates the crystallinity of final nanoparticles in a seeded-growth process. Although the formation of monocrystalline particles does require the use of single-crystal seeds, twin planes may stem from either single-or polycrystalline seeds. However, experimental control over twin-plane formation remains difficult to achieve synthetically. Here, we show that a careful interplay between kinetics and selective surface passivation offers a unique handle over the emergence of twin planes (in decahedra and triangles) during the growth over single-crystalline gold nanoparticles of quasi-spherical shape. Twinning can be suppressed under conditions of slow kinetics in the presence of silver ions, yielding single-crystalline particles with high-index facets.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 18
DOI: 10.1021/ACSOMEGA.6B00066
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“The wear of polished and glazed zirconia against enamel”. Janyavula S, Lawson N, Çakir D, Beck P, Ramp LC, Burgess JO, Journal Of Prosthetic Dentistry 109, 22 (2013). http://doi.org/10.1016/S0022-3913(13)60005-0
Abstract: Statement of problem. The wear of tooth structure opposing anatomically contoured zirconia crowns requires further investigation. Purpose. The purpose of this in vitro study was to measure the roughness and wear of polished, glazed, and polished then reglazed zirconia against human enamel antagonists and compare the measurements to those of veneering porcelain and natural enamel. Material and methods. Zirconia specimens were divided into polished, glazed, and polished then reglazed groups (n=8). A veneering porcelain (Ceramco3) and enamel were used as controls. The surface roughness of all pretest specimens was measured. Wear testing was performed in the newly designed Alabama wear testing device. The mesiobuccal cusps of extracted molars were standardized and used as antagonists. Three-dimensional (3D) scans of the specimens and antagonists were obtained at baseline and after 200 000 and 400 000 cycles with a profilometer. The baseline scans were superimposed on the posttesting scans to determine volumetric wear. Data were analyzed with a 1-way ANOVA and Tukey Honestly Significant Difference (HSD) post hoc tests (alpha=.05) Results. Surface roughness ranked in order of least rough to roughest was: polished zirconia, glazed zirconia, polished then reglazed zirconia, veneering porcelain, and enamel. For ceramic, there was no measureable loss on polished zirconia, moderate loss on the surface of enamel, and significant loss on glazed and polished then reglazed zirconia. The highest ceramic wear was exhibited by the veneering ceramic. For enamel antagonists, polished zirconia caused the least wear, and enamel caused moderate wear. Glazed and polished then reglazed zirconia showed significant opposing enamel wear, and veneering porcelain demonstrated the most. Conclusions. Within the limitations of the study, polished zirconia is wear-friendly to the opposing tooth. Glazed zirconia causes more material and antagonist wear than polished zirconia. The surface roughness of the zirconia aided in predicting the wear of the opposing dentition. (J Prosthet Dent 2013;109:22-29)
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.095
Times cited: 89
DOI: 10.1016/S0022-3913(13)60005-0
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“Functional silicene and stanene nanoribbons compared to graphene: electronic structure and transport”. van den Broek B, Houssa M, Iordanidou K, Pourtois G, Afanas'ev VV, Stesmans A, 2D materials 3, 015001 (2016). http://doi.org/10.1088/2053-1583/3/1/015001
Abstract: Since the advent of graphene, other 2D materials have garnered interest; notably the single element materials silicene, germanene, and stanene. Weinvestigate the ballistic current-voltage (I-V) characteristics of armchair silicene and stanene armchair nanoribbons (AXNRs with X = Si, Sn) using a combination of density functional theory and non-equilibrium Green's functions. The impact of out-of-plane electric field and in-plane uniaxial strain on the ribbon geometries, electronic structure, and (I-V)s are considered and contrasted with graphene. Since silicene and stanene are sp(2)/sp(3) buckled layers, the electronic structure can be tuned by an electric field that breaks the sublattice symmetry, an effect absent in graphene. This decreases the current by similar to 50% for Sn, since it has the largest buckling. Uniaxial straining of the ballistic channel affects the AXNR electronic structure in multiple ways: it changes the bandgap and associated effective carrier mass, and creates a local buckling distortion at the lead-channel interface which induces a interface dipole. Due to the increasing sp(3) hybridization character with increasing element mass, large reconstructions rectify the strained systems, an effect absent in sp(2) bonded graphene. This results in a smaller strain effect on the current: a decrease of 20% for Sn at 15% tensile strain compared to a similar to 75% decrease for C.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 6.937
Times cited: 19
DOI: 10.1088/2053-1583/3/1/015001
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