|
Snoeckx R (2017) Plasma technology : a novel solution for CO2 conversion? Antwerpen
Keywords: Doctoral thesis; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
|
|
|
Alania M (2017) Quantification of 3D atomic positions for nanoparticles using scanning transmission electron microscopy: statistical parameter estimation, dose-limited precision and optimal experimental design. Antwerpen
Keywords: Doctoral thesis; Electron microscopy for materials research (EMAT)
|
|
|
Huygh S (2017) Towards a fundamental understanding of plasma : TiO2 catalyst interaction for greenhouse gas conversion. Universiteit Antwerpen, Antwerpen
Keywords: Doctoral thesis; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
|
|
|
Paria Sena R (2017) Structure characterization of triple perovskites and related systems by transmission electron microscopy. Antwerpen
Keywords: Doctoral thesis; Electron microscopy for materials research (EMAT)
|
|
|
Zanaga D (2017) Advanced algorithms for quantitative electron tomography. Antwerpen
Keywords: Doctoral thesis; Electron microscopy for materials research (EMAT)
|
|
|
Dabaghmanesh S (2017) Atomistic modeling of the structural and electronic properties of Cr-based oxides and their potential application as TCO materials. Antwerpen
Keywords: Doctoral thesis; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
|
|
|
Garcí,a Sá,nchez C (2017) Quantifying inflow uncertainties for CFD simulations of dispersion in the atmospheric boundary layer. Antwerpen
Keywords: Doctoral thesis; Electron microscopy for materials research (EMAT)
|
|
|
Bladt E (2017) Two- and three-dimensional transmission electron microscopy of colloidal nanoparticles : from struture to composition. Antwerpen
Keywords: Doctoral thesis; Electron microscopy for materials research (EMAT)
|
|
|
Mirzakhani M (2017) Electronic properties and energy levels of graphene quantum dots. Antwerpen
Keywords: Doctoral thesis; Condensed Matter Theory (CMT)
|
|
|
Aierken Y (2017) First-principles studies of novel two-dimensional materials and their physical properties. Antwerpen
Keywords: Doctoral thesis; Condensed Matter Theory (CMT)
|
|
|
van den Bos KHW (2017) Quantitative atomic resolution transmission electron microscopy for heterogeneous nanomaterials. Antwerpen
Keywords: Doctoral thesis; Electron microscopy for materials research (EMAT)
|
|
|
Meledin A (2017) Nanostructure of superconducting tapes : a study by electron microscopy. Antwerp
Keywords: Doctoral thesis; Electron microscopy for materials research (EMAT)
|
|
|
“BiVo4/3DOM TiO2 nanocomposites : effect of BiVO4 as highly efficient visible light sensitizer for highly improved visible light photocatalytic activity in the degradation of dye pollutants”. Zalfani M, Hu Z-Y, Yu W-B, Mahdouani M, Bourguiga R, Wu M, Li Y, Van Tendeloo G, Djoued Y, Su B-L, Applied catalysis : B : environmental 205, 121 (2017). http://doi.org/10.1016/J.APCATB.2016.12.019
Abstract: A series of BiVO4/3DOM TiO2 nanocomposites have been synthesized and their photocatalytic activity was investigated under visible light irradiation using the RhB dye as model pollutant molecule in an aqueous solution. The effect of the amount of BiVO4 as visible light sensitizer on the photocatalytic activity of BiVO4/3DOM TiO2 nanocomposites was highlighted. The heterostructured composite system leads to much higher photocatalytic efficiencies than bare 3DOM TiO2 and BiVO4 nanoparticles. As the proportion of BiVO4 in BiVO4/3DOM TiO2 nanocomposites increases from 0.04 to 0.6, the photocatalytic performance of the BiVO4/3DOM TiO2 nanocomposites increases and then decreases after reaching a maximum at 0.2. This improvement in photocatalytic perfomance is related to 1) the interfacial electron transfer efficiency between the coupled materials, 2) the 3DOM TiO2 inverse opal structure with interconnected pores providing an easy mass transfer of the reactant molecules and high accessibility to the active sites and large surface area and 3) the effect of light sensitizer of BiVO4. Intensive studies on structural, textural, optical and surface properties reveal that the electronic interactions between BiVO4 and TiO2 lead to an improved charge separation of the coupled BiVO4/TiO2 system. The photogenerated charge carrier densities increase with increasing the BiVO4 content, which acts as visible light sensitizer to the TiO2 and is responsible for the enhancement in the rate of photocatalytic degradation. However, the photocatalytic activity is reduced when the BiVO4 amount is much higher than that of 3DOM TiO2. Two reasons could account for this behavior. First, with increasing BiVO4 content, the photogenerated electron/hole pairs are accumulated at the surface of the BiVO4 nanoparticles and the recombination rate increases as shown by the PL results. Second, decreasing the amount of 3DOM TiO2 in the nanocomposite decreases the surface area as shown by the BET results. Moreover, the poor adsorptive properties of the BiVO4 photocatalyst also affect the photocatalytic performance, in particular at higher BiVO4 content. The present work demonstrates that BiVO4/3DOM TiO2 is a very promising heterojunction system for visible light photocatalytic applications.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.446
Times cited: 52
DOI: 10.1016/J.APCATB.2016.12.019
|
|
|
“Structure and magnetic properties of Sm(Fe,Si)(9)C/alpha-Fe nanocomposite magnets”. Bez R, Zehani K, Batuk M, Van Tendeloo G, Mliki N, Bessais L, Journal of alloys and compounds 695, 810 (2017). http://doi.org/10.1016/J.JALLCOM.2016.10.122
Abstract: SmFe8.75 Si-0.25 C/alpha-Fe nanocomposites have been successfully synthesized using high energy milling, followed by annealing at 750 degrees C. The crystal structure of these compounds was characterized by the Rietveld method using powder X-ray diffraction data. By increasing the concentration of Sm, we observed a decrease in the amount of alpha-Fe phase. The morphology of the samples was determined by scanning and transmission electron microscopy. The average grain size is about 20 nm. The magnetic properties were investigated at room temperature and at 10 K. A ferromagnetic behavior was observed in all samples at both temperatures. An increase of the soft magnetic phase alpha-Fe induced an increase in the magnetization and a decrease in coercivity. (C) 2016 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 3.133
Times cited: 1
DOI: 10.1016/J.JALLCOM.2016.10.122
|
|
|
“Tuning of PCDTBT : PC71BM blend nanoparticles for eco-friendly processing of polymer solar cells”. D'Olieslaeger L, Pfannmöller M, Fron E, Cardinaletti I, Van der Auweraer M, Van Tendeloo G, Bals S, Maes W, Vanderzande D, Manca J, Ethirajan A, Solar energy materials and solar cells 159, 179 (2017). http://doi.org/10.1016/J.SOLMAT.2016.09.008
Abstract: We report the controlled preparation of water processable nanoparticles (NPs) employing the push-pull polymer PCDTBT and the fullerene acceptor PC71BM in order to enable solar cell processing using eco-friendly solvent (i.e. water). The presented method provides the possibility to separate the formation of the active layer blend and the deposition of the active layer into two different processes. For the first time, the benefits of aqueous processability for the high-potential class of push-pull polymers, generally requiring high boiling solvents, are made accessible. With our method we demonstrate excellent control over the blend stoichiometry and efficient mixing. Furthermore, we provide visualization of the nano morphology of the different NPs to obtain structural information down to similar to 2 nm resolution using advanced analytical electron microscopy. The imaging directly reveals very small compositional demixing in the PCDTBT:PC71BM blend NPs, in the size range of about <5 nm, indicating fine mixing at the molecular level. The suitability of the proposed methodology and materials towards the aspects of eco-friendly processing of organic solar cells is demonstrated through a processing of lab scale NPs solar cell prototypes reaching a power conversion efficiency of 1.9%. (C) 2016 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 4.784
Times cited: 32
DOI: 10.1016/J.SOLMAT.2016.09.008
|
|
|
“Resistivity scaling in metallic thin films and nanowires due to grain boundary and surface roughness scattering”. Moors K, Sorée B, Magnus W, Microelectronic engineering 167, 37 (2017). http://doi.org/10.1016/J.MEE.2016.10.015
Abstract: A modeling approach, based on an analytical solution of the semiclassical multi-subband Boltzmann transport equation, is presented to study resistivity scaling in metallic thin films and nanowires due to grain boundary and surface roughness scattering. While taking into account the detailed statistical properties of grains, roughness and barrier material as well as the metallic band structure and quantum mechanical aspects of scattering and confinement, the model does not rely on phenomenological fitting parameters. (C) 2016 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 1.806
Times cited: 6
DOI: 10.1016/J.MEE.2016.10.015
|
|
|
“Dynamics of skyrmions and edge states in the resistive regime of mesoscopic p-wave superconductors”. Fernández Becerra V, Milošević, MV, Physica: C : superconductivity 533, 91 (2017). http://doi.org/10.1016/J.PHYSC.2016.07.002
Abstract: In a mesoscopic sample of a chiral p-wave superconductor, novel states comprising skyrmions and edge states have been stabilized in out-of-plane applied magnetic field. Using the time-dependent Ginzburg-Landau equations we shed light on the dynamic response of such states to an external applied current. Three different regimes are obtained, namely, the superconducting (stationary), resistive (non-stationary) and normal regime, similarly to conventional s-wave superconductors. However, in the resistive regime and depending on the external current, we found that moving skyrmions and the edge state behave distinctly different from the conventional kinematic vortex, thereby providing new fingerprints for identification of p-wave superconductivity. (C) 2016 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.404
Times cited: 3
DOI: 10.1016/J.PHYSC.2016.07.002
|
|
|
“Electrochemically activated MnO as a cathode material for sodium-ion batteries”. Zhang L, Batuk D, Chen G, Tarascon J-M, Electrochemistry communications 77, 81 (2017). http://doi.org/10.1016/J.ELECOM.2017.02.020
Abstract: Besides classical electrode materials pertaining to Li-ion batteries, recent interest has been devoted to pairs of active redox composites having a redox center and an intercalant source. Taking advantage of the NaPFG salt decomposition above 4.2 V. we extrapolate this concept to the electrochemical in situ preparation of F-based MnO composite electrodes for Na-ion batteries. Such electrodes exhibit a reversible discharge capacity of 145 mAh g(-1) at room temperature. The amorphization of pristine MnO electrode after activation is attributed to the electrochemical grinding effect caused by substantial atomic migration and lattice strain build-up upon cycling. (C) 2017 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.396
Times cited: 8
DOI: 10.1016/J.ELECOM.2017.02.020
|
|
|
“Ship-in-a-bottle CMPO in MIL-101(Cr) for selective uranium recovery from aqueous streams through adsorption”. De Decker J, Folens K, De Clercq J, Meledina M, Van Tendeloo G, Du Laing G, Van Der Voort P, Journal of hazardous materials 335, 1 (2017). http://doi.org/10.1016/J.JHAZMAT.2017.04.029
Abstract: Mesoporous MIL-101(Cr) is used as host for a ship-in-a-bottle type adsorbent for selective U(VI) recovery from aqueous environments. The acid-resistant cage-type MOF is built in-situ around N,N-Diisobutyl-2-(octylphenylphosphoryl)acetamide (CMPO), a sterically demanding ligand with high U(VI) affinity. This one-step procedure yields an adsorbent which is an ideal compromise between homogeneous and heterogeneous systems, where the ligand can act freely within the pores of MIL-101, without leaching, while the adsorbent is easy separable and reusable. The adsorbent was characterized by XRD, FTIR spectroscopy, nitrogen adsorption, XRF, ADF-STEM and EDX, to confirm and quantify the successful encapsulation of the CMPO in MIL-101, and the preservation of the host. Adsorption experiments with a central focus on U(VI) recovery were performed. Very high selectivity for U(VI) was observed, while competitive metal adsorption (rare earths, transition metals...) was almost negligible. The adsorption capacity was calculated at 5.32 mg U/g (pH 3) and 27.99 mg U/g (pH 4), by fitting equilibrium data to the Langmuir model. Adsorption kinetics correlated to the pseudo-second-order model, where more than 95% of maximum uptake is achieved within 375 min. The adsorbed U(VI) is easily recovered by desorption in 0.1 M HNO3. Three adsorption/desorption cycles were performed. (C) 2017 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.065
Times cited: 35
DOI: 10.1016/J.JHAZMAT.2017.04.029
|
|
|
“Advanced turbulence models and boundary conditions for flows around different configurations of ground-mounted buildings”. Longo R, Ferrarotti M, Garcia Sánchez C, Derudi M, Parente A, Journal of wind engineering and industrial aerodynamics 167, 160 (2017). http://doi.org/10.1016/J.JWEIA.2017.04.015
Abstract: When dealing with Atmospheric Boundary Layer (ABL) simulations, commercial computational fluid dynamics (CFD) acquires a strategic resonance. Thanks to its good compromise between accuracy of results and calculation time, RANS still represents a valid alternative to more resource-demanding methods. However, focusing on the models' performances in urban studies, LES generally outmatches RANS results, even if the former is at least one order of magnitude more expensive. Consequently, the present work aims to propose a variety of approaches meant to solve some of the major problems linked to RANS simulations and to further improve its accuracy in typical urban contexts. All of these models are capable of switching from an undisturbed flux formulation to a disturbed one through a local deviation or a marker function. For undisturbed flows, a comprehensive approach is adopted, solving the issue of the erroneous stream-wise gradients affecting the turbulent profiles. Around obstacles, Non-Linear Eddy-Viscosity closures are adopted, due to their prominent capability in capturing the anisotropy of turbulence. The purpose of this work is then to propose a new Building Influence Area concept and to offer more affordable alternatives to LES simulations without sacrificing a good grade of accuracy.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.049
Times cited: 9
DOI: 10.1016/J.JWEIA.2017.04.015
|
|
|
“Cobalt location in p-CoOxIn-SnO2 nanocomposites : correlation with gas sensor performances”. Vladimirova SA, Rumyantseva MN, Filatova DG, Chizhov AS, Khmelevsky NO, Konstantinova EA, Kozlovsky VF, Marchevsky AV, Karakulina OM, Hadermann J, Gaskov AM, Journal of alloys and compounds 721, 249 (2017). http://doi.org/10.1016/JJALLCOM.2017.05.332
Abstract: Nanocomposites CoOx/SnO2 based on tin oxide powders with different crystallinity have been prepared by wet chemical synthesis and characterized in detail by ICP-MS, XPS, EPR, XRD, HAADF-STEM imaging and EDX-STEM mapping. It was shown that cobalt is distributed differently between the bulk and surface of SnO2 nanocrystals, which depends on the crystallinity of the SnO2 matrix. The measurements of gas sensor properties have been carried out during exposure to CO (10 ppm), and H2S (2 ppm) in dry air. The decrease of sensor signal toward CO was attributed to high catalytic activity of Co3O4 leading to oxidation of carbon monoxide entirely on the surface of catalyst particles. The formation of a p-CoOx/n-SnO2 heterojunction results in high sensitivity of nanocomposites in H2S detection. The conductance significantly changed in the presence of H2S, which was attributed to the formation of metallic cobalt sulfide and removal of the p – n junction. (C) 2017 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 3.133
DOI: 10.1016/JJALLCOM.2017.05.332
|
|
|
“Quantum canonical ensemble : a projection operator approach”. Magnus W, Lemmens L, Brosens F, Physica: A : theoretical and statistical physics 482, 1 (2017). http://doi.org/10.1016/J.PHYSA.2017.04.069
Abstract: Knowing the exact number of particles N, and taking this knowledge into account, the quantum canonical ensemble imposes a constraint on the occupation number operators. The constraint particularly hampers the systematic calculation of the partition function and any relevant thermodynamic expectation value for arbitrary but fixed N. On the other hand, fixing only the average number of particles, one may remove the above constraint and simply factorize the traces in Fock space into traces over single-particle states. As is well known, that would be the strategy of the grand-canonical ensemble which, however, comes with an additional Lagrange multiplier to impose the average number of particles. The appearance of this multiplier can be avoided by invoking a projection operator that enables a constraint-free computation of the partition function and its derived quantities in the canonical ensemble, at the price of an angular or contour integration. Introduced in the recent past to handle various issues related to particle-number projected statistics, the projection operator approach proves beneficial to a wide variety of problems in condensed matter physics for which the canonical ensemble offers a natural and appropriate environment. In this light, we present a systematic treatment of the canonical ensemble that embeds the projection operator into the formalism of second quantization while explicitly fixing N, the very number of particles rather than the average. Being applicable to both bosonic and fermionic systems in arbitrary dimensions, transparent integral representations are provided for the partition function Z(N) and the Helmholtz free energy F-N as well as for two- and four-point correlation functions. The chemical potential is not a Lagrange multiplier regulating the average particle number but can be extracted from FN+1 – F-N, as illustrated for a two-dimensional fermion gas. (C) 2017 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Theory of quantum systems and complex systems; Condensed Matter Theory (CMT)
Impact Factor: 2.243
Times cited: 1
DOI: 10.1016/J.PHYSA.2017.04.069
|
|
|
“Structures and spectroscopic properties of sulfur-nitrogen-pnictogen chains : R2P-N=S=N-PR2 and R2P-N=S=N-AsR2”. Bal KM, Cautereels J, Blockhuys F, Journal of molecular structure 1132, 102 (2017). http://doi.org/10.1016/J.MOLSTRUC.2016.08.008
Abstract: The conformational and configurational preferences of Me2PNSNPMe2 (3) and Me2PNSNAsMe2 (4) have been identified using quantum chemical calculations at the DFT/B3LYP/6-311+G* level of theory. An approach in which energetic, structural (geometries and bond orders), electronic (analysis of the electron density) and spectroscopic properties are combined leads to the conclusion that these sulfur-nitrogen-pnictogen chains share many of the properties of their chalcogen-nitrogen analogues but that the through-space intramolecular interactions favouring the Z,Z configuration are even weaker than in these latter compounds. The results of this analysis also lead to an unambiguous assignment of the variable-temperature 31P and 15N NMR spectra of these compounds and their structures both in solution and in the solid state.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.753
DOI: 10.1016/J.MOLSTRUC.2016.08.008
|
|
|
“Thermal creep properties of Ti-stabilized DIN 1.4970 (15-15Ti) austenitic stainless steel pressurized cladding tubes”. Cautaerts N, Delville R, Dietz W, Verwerft M, Journal of nuclear materials 493, 154 (2017). http://doi.org/10.1016/J.JNUCMAT.2017.06.013
Abstract: This paper presents a large database of thermal creep data from pressurized unirradiated DIN 1.4970 Ti-stabilized austenitic stainless steel (i.e. EN 1515CrNiMoTiB or “15-15Ti”) cladding tubes from more than 1000 bi-axial creep tests conducted during the fast reactor R&D program of the DeBeNe (Deutschland-Belgium- Netherlands) consortium between the 1960's to the late 1980's. The data comprises creep rate and time-to-rupture between 600 and 750 degrees C and a large range of stresses. The data spans tests on material from around 70 different heats and 30 different melts. Around one fourth of the data was obtained from cold worked material, the rest was obtained on cold worked + aged (800 degrees C, 2 h) material. The data are graphically presented in log-log graphs. The creep rate data is fit with a sinh correlation, the time to rupture data is fit with a modified exponential function through the Larson-Miller parameter. Local equivalent parameters to Norton's law are calculated and compared to literature values for these types of steels and related to possible creep mechanisms. Some time to rupture data above 950 degrees C is compared to literature dynamic recrystallization data. Time to rupture data between 600 and 750 degrees C is also compared to literature data from 316 steel. Time to rupture was correlated directly to creep rate with the Monkman-Grant relationship at different temperatures. (C) 2017 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 2.048
Times cited: 5
DOI: 10.1016/J.JNUCMAT.2017.06.013
|
|
|
“Bandgap measurement of high refractive index materials by off-axis EELS”. Vatanparast M, Egoavil R, Reenaas TW, Verbeeck J, Holmestad R, Vullum PE, Ultramicroscopy 182, 92 (2017). http://doi.org/10.1016/J.ULTRAMIC.2017.06.019
Abstract: In the present work Cs aberration corrected and monochromated scanning transmission electron microscopy electron energy loss spectroscopy (STEM-EELS) has been used to explore experimental setups that allow bandgaps of high refractive index materials to be determined. Semi-convergence and collection angles in the mu rad range were combined with off-axis or dark field EELS to avoid relativistic losses and guided light modes in the low loss range to contribute to the acquired EEL spectra. Off-axis EELS further supressed the zero loss peak and the tail of the zero loss peak. The bandgap of several GaAs-based materials were successfully determined by simple regression analyses of the background subtracted EEL spectra. The presented set-up does not require that the acceleration voltage is set to below the. Cerenkov limit and can be applied over the entire acceleration voltage range of modern TEMs and for a wide range of specimen thicknesses. (C) 2017 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.843
Times cited: 3
DOI: 10.1016/J.ULTRAMIC.2017.06.019
|
|
|
“Optimization of NBED simulations for disc-detection measurements”. Grieb T, Krause FF, Mahr C, Zillmann D, Müller-Caspary K, Schowalter M, Rosenauer A, Ultramicroscopy 181, 50 (2017). http://doi.org/10.1016/J.ULTRAMIC.2017.04.015
Abstract: Nano-beam electron diffraction (NBED) is a method which can be applied to measure lattice strain and polarisation fields in strained layer heterostructures and transistors. To investigate precision, accuracy and spatial resolution of such measurements in dependence of properties of the specimen as well as electron optical parameters, simulations of NBED patterns are required which allow to predict the result of common disc-detection algorithms. In this paper we demonstrate by focusing on the detection of the central disc in crystalline silicon that such simulations require to take several experimental characteristics into account in order to obtain results which are comparable to those from experimental NBED patterns. These experimental characteristics are the background intensity, the presence of Poisson noise caused by electron statistics and blurring caused by inelastic scattering and by the transfer quality of the microscope camera. By means of these optimized simulations, different effects of specimen properties on disc detection – such as strain, surface morphology and compositional changes on the nanometer scale – are investigated and discussed in the context of misinterpretation in experimental NBED evaluations. It is shown that changes in surface morphology and chemical composition lead to measured shifts of the central disc in the NBED pattern of tens to hundreds of grad. These shifts are of the same order of magnitude or even larger than shifts that could be caused by an electric polarisation field in the range of MV/cm. (C) 2017 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.843
Times cited: 6
DOI: 10.1016/J.ULTRAMIC.2017.04.015
|
|
|
“The formation of Cr2O3 nanoclusters over graphene sheet and carbon nanotubes”. Dabaghmanesh S, Neek-Amal M, Partoens B, Neyts EC, Chemical physics letters 687, 188 (2017). http://doi.org/10.1016/J.CPLETT.2017.09.005
Keywords: A1 Journal article; Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.815
Times cited: 2
DOI: 10.1016/J.CPLETT.2017.09.005
|
|
|
“Paths to collapse for isolated skyrmions in few-monolayer ferromagnetic films”. Stosic D, Mulkers J, Van Waeyenberge B, Ludermir TB, Milošević, MV, Physical review B 95, 214418 (2017). http://doi.org/10.1103/PhysRevB.95.214418
Abstract: Magnetic skyrmions are topological spin configurations in materials with chiral Dzyaloshinskii-Moriya interaction (DMI), that are potentially useful for storing or processing information. To date, DMI has been found in few bulk materials, but can also be induced in atomically thin magnetic films in contact with surfaces with large spin-orbit interactions. Recent experiments have reported that isolated magnetic skyrmions can be stabilized even near room temperature in few-atom-thick magnetic layers sandwiched between materials that provide asymmetric spin-orbit coupling. Here we present the minimum-energy path analysis of three distinct mechanisms for the skyrmion collapse, based on ab initio input and the performed atomic-spin simulations. We focus on the stability of a skyrmion in three atomic layers of Co, either epitaxial on the Pt(111) surface or within a hybrid multilayer where DMI nontrivially varies per monolayer due to competition between different symmetry breaking from two sides of the Co film. In laterally finite systems, their constrained geometry causes poor thermal stability of the skyrmion toward collapse at the boundary, which we show to be resolved by designing the high-DMI structure within an extended film with lower or no DMI.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 48
DOI: 10.1103/PhysRevB.95.214418
|
|
|
“One-Step Microheterogeneous Formation of Rutile@Anatase Core–Shell Nanostructured Microspheres Discovered by Precise Phase Mapping”. Tarasov A, Hu Z-Y, Meledina M, Trusov G, Goodilin E, Van Tendeloo G, Dobrovolsky Y, The journal of physical chemistry: C : nanomaterials and interfaces 121, 4443 (2017). http://doi.org/10.1021/acs.jpcc.6b12991
Abstract: Nanostructured core−shell microspheres with a rough rutile core and a thin anatase shell are synthesized via a one-step heterogeneous templated hydrolysis process of TiCl4 vapor on the aerosol water−air interface. The rutile-in-anatase core−shell structure has been evidenced by different electron microscopy techniques, including electron energy-loss spectroscopy and 3D electron tomography. A new mechanism for the formation of a crystalline rutile core inside the anatase shell is proposed based on a statistical evaluation of a large number of electron microscopy data. We found that the control over the TiCl4 vapor pressure, the ratio between TiCl4 and H2O aerosol, and the reaction conditions plays a crucial role in the formation of the core−shell morphology and increases the yield of nanostructured microspheres.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 4.536
Times cited: 4
DOI: 10.1021/acs.jpcc.6b12991
|
|
|
“Application of the weighted-density approximation to the accurate description of electron-positron correlation effects in materials”. Callewaert V, Saniz R, Barbiellini B, Bansil A, Partoens B, Physical review B 96, 085135 (2017). http://doi.org/10.1103/PhysRevB.96.085135
Abstract: We discuss positron-annihilation lifetimes for a set of illustrative bulk materials within the framework of the weighted-density approximation (WDA). The WDA can correctly describe electron-positron correlations in strongly inhomogeneous systems, such as surfaces, where the applicability of (semi-)local approximations is limited. We analyze the WDA in detail and show that the electrons which cannot screen external charges efficiently, such as the core electrons, cannot be treated accurately via the pair correlation of the homogeneous electron gas. We discuss how this problem can be addressed by reducing the screening in the homogeneous electron gas by adding terms depending on the gradient of the electron density. Further improvements are obtained when core electrons are treated within the LDA and the valence electron using the WDA. Finally, we discuss a semiempirical WDA-based approach in which a sum rule is imposed to reproduce the experimental lifetimes.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 6
DOI: 10.1103/PhysRevB.96.085135
|
|