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“Time dependent properties of classical artificial atoms”. Schweigert VA, Peeters FM, Journal of physics : condensed matter 10, 2417 (1998). http://doi.org/10.1088/0953-8984/10/11/006
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.649
Times cited: 18
DOI: 10.1088/0953-8984/10/11/006
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“Topotactic transformation of the cationic conductor Li4Mo5O17 into a rock salt type oxide Li12Mo5O17”. Pop N, Pralong V, Caignaert V, Colin JF, Malo S, Van Tendeloo G, Raveau B, Chemistry of materials 21, 3242 (2009). http://doi.org/10.1021/cm900767m
Abstract: Intercalation of lithium in the ribbon structure Li4Mo5O17 has been achieved, using both electrochemistry and soft chemistry. The ab initio structure determination of the ¡°Mo−O¡± framework of Li12Mo5O17 shows that the [Mo5O17]¡Þ ribbons keep the same arrangement of edge sharing MoO6 octahedra and the same orientation as in the parent structure but that a topotactic antidistortion of the ribbons appears, as a result of the larger size of Mo4+ in ¡°Li12¡± compared to Mo6+ in ¡°Li4¡±. On the basis of bond valence calculations, it is observed that 12 octahedral sites are available for Li+ in the new structure so that an ordered hypothetical rock salt type structure can be proposed for Li12Mo5O17. After the first Li insertion, a stable reversible capacity of 100 mA¡¤h/g is maintained after 20 cycles. A complete structural reversibility leading back to the ribbon type Li4Mo5O17 structure is obtained using a very low rate of C/100. The exploration of the Li mobility in those oxides shows that Li4Mo5O17 is a cationic conductor with ¦Ò = 10−3.5 S/cm at 500 ¡ãC and Ea = 0.35 eV.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 18
DOI: 10.1021/cm900767m
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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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“Unconventional vortex dynamics in mesoscopic superconducting corbino disks”. Lin NS, Misko VR, Peeters FM, Physical review letters 102, 197003 (2009). http://doi.org/10.1103/PhysRevLett.102.197003
Abstract: The discrete shell structure of vortex matter strongly influences the flux dynamics in mesoscopic superconducting Corbino disks. While the dynamical behavior is well understood in large and in very small disks, in the intermediate-size regime it occurs to be much more complex and unusual, due to (in)commensurability between the vortex shells. We demonstrate unconventional vortex dynamics (inversion of shell velocities with respect to the gradient driving force) and angular melting (propagating from the boundary where the shear stress is minimum, towards the center) in mesoscopic Corbino disks.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 8.462
Times cited: 18
DOI: 10.1103/PhysRevLett.102.197003
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“Unexpected ordering behaviour of Pt3Al intermetallic precipitates”. Douglas A, Neethling JH, Santamarta R, Schryvers D, Cornish LA, Journal of alloys and compounds 432, 96 (2007). http://doi.org/10.1016/j.jallcom.2006.05.106
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.133
Times cited: 18
DOI: 10.1016/j.jallcom.2006.05.106
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“A novel red Ca8.5Pb0.5Eu(PO4)7 phosphor for light emitting diodes application”. Deyneko DV, Morozov VA, Hadermann J, Savon AE, Spassky DA, Stefanovich SY, Belik AA, Lazoryak BI, Journal of alloys and compounds 647, 965 (2015). http://doi.org/10.1016/j.jallcom.2015.06.123
Abstract: Ca9-xPbxEu(PO4)(7) (0 <= x <= 1) solid solutions with a whitlockite-type (or beta-Ca-3(PO4)(2)-type) structure (sp.gr. R3c) were prepared by a standard solid-state method in air. Their luminescent properties under near-ultraviolet (n-UV) light were investigated. Excitation spectra of Ca9-xPbxEu(PO4)(7) showed the strongest absorption at about 395 nm, which matches well with commercially available n-UV-emitting GaN-based LED chips. Emission spectra indicated an intense red emission due to the D-5(0) -> F-7(2) transition of Eu3+, with a maximum in the intensity for Ca8.5Pb0.5Eu(PO4)(7). The emission intensity of Ca8.5Pb0.5Eu(PO4)(7) was about 1.8 times higher than that of a Ca9Eu(PO4)(7) phosphor. We suggest that the introduction of Pb2+ is an efficient approach to enhance luminescence properties of such phosphors. We clarified the influence of the Ca2+/Pb2+ substitution on intensities of three bands for the D-5(0) -> F-7(0) transition in excitation spectra of Ca9-xPbxEu(PO4)(7). In addition, we found a reversible first-order phase transition from R3c to R (3) over barc symmetry by second-harmonic generation in the range from 753 K (x = 1) to 846 K (x = 0). (C) 2015 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: 18
DOI: 10.1016/j.jallcom.2015.06.123
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“Optical and photoelectrical properties of nanocrystalline indium oxide with small grains”. Forsh EA, Abakumov AM, Zaytsev VB, Konstantinova EA, Forsh PA, Rumyantseva MN, Gaskov AM, Kashkarov PK, Thin solid films : an international journal on the science and technology of thin and thick films 595, 25 (2015). http://doi.org/10.1016/j.tsf.2015.10.053
Abstract: Optical properties, spectral dependence of photoconductivity and photoconductivity decay in nanocrystalline indium oxide In2O3 are studied. A number of nanostructured In2O3 samples with various nanocrystals size are prepared by sol-gel method and characterized using various techniques. The mean nanocrystals size varies from 7 to 8 nm to 39-41 nm depending on the preparation conditions. Structural characterization of the In2O3 samples is performed by means of transmission electron microscopy and X-ray powder diffraction. The combined analysis of ultraviolet-visible absorption spectroscopy and diffuse reflectance spectroscopy shows that nanostructuring leads to the change in optical band gap: optical band gap of the In2O3 samples (with an average nanocrystal size from 7 to 41 nm) is equal to 2.8 eV. We find out the correlation between spectral dependence of photoconductivity and optical properties of nanocrystalline In2O3: sharp increase in photoconductivity was observed to begin at 2.8 eV that is equal to the optical bandgap in the In2O3 samples, and reached its maximum at 3.2-3.3 eV. The combined analysis of the slow photoconductivity decay in air, vacuum and argon, that was accurately fitted by a stretched-exponential function, and electron paramagnetic resonance (EPR) measurements shows that the kinetics of photoconductivity decay is strongly depended on the presence of oxygen molecules in the ambient of In2O3 nanocrystals. There is the quantitative correlation between EPR and photoconductivity data. Based on the obtained data we propose the model clearing up the phenomenon of permanent photoconductivity decay in nanocrystalline In2O3. (C) 2015 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.879
Times cited: 18
DOI: 10.1016/j.tsf.2015.10.053
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“QDB: a new database of plasma chemistries and reactions”. Tennyson J, Rahimi S, Hill C, Tse L, Vibhakar A, Akello-Egwel D, Brown DB, Dzarasova A, Hamilton JR, Jaksch D, Mohr S, Wren-Little K, Bruckmeier J, Agarwal A, Bartschat K, Bogaerts A, Booth J-P, Goeckner MJ, Hassouni K, Itikawa Y, Braams BJ, Krishnakumar E, Laricchiuta A, Mason NJ, Pandey S, Petrovic ZL, Pu Y-K, Ranjan A, Rauf S, Schulze J, Turner MM, Ventzek P, Whitehead JC, Yoon J-S, Plasma sources science and technology 26, 055014 (2017). http://doi.org/10.1088/1361-6595/aa6669
Abstract: One of the most challenging and recurring problems when modeling plasmas is the lack of data on the key atomic and molecular reactions that drive plasma processes. Even when there are data for some reactions, complete and validated datasets of chemistries are rarely available. This hinders research on plasma processes and curbs development of industrial applications. The QDB project aims to address this problem by providing a platform for provision, exchange, and validation of chemistry datasets. A new data model developed for QDB is presented. QDB collates published data on both electron scattering and heavy-particle reactions. These data are formed into reaction sets, which are then validated against experimental data where possible. This process produces both complete chemistry sets and identifies key reactions that are currently unreported in the literature. Gaps in the datasets can be filled using established theoretical methods. Initial validated chemistry sets for SF6/CF4/O2 and SF6/CF4/N2/H2 are presented as examples.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.302
Times cited: 18
DOI: 10.1088/1361-6595/aa6669
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“Small-angle X-ray scattering and light scattering study of hybrid nanoparticles composed of thermoresponsive triblock copolymer F127 and thermoresponsive statistical polyoxazolines with hydrophobic moieties”. Bogomolova A, Hruby M, Panek J, Rabyk M, Turner S, Bals S, Steinhart M, Zhigunov A, Sedlacek O, Stepanek P, Filippov SK;, Journal of applied crystallography 46, 1690 (2013). http://doi.org/10.1107/S0021889813027064
Abstract: A combination of new thermoresponsive statistical polyoxazolines, poly[(2-butyl-2-oxazoline)-stat-(2-isopropyl-2-oxazoline)] [pBuOx-co-piPrOx], with different hydrophobic moieties and F127 surfactant as a template system for the creation of thermosensitive nanoparticles for radionuclide delivery has recently been tested [Pánek, Filippov, Hrubý, Rabyk, Bogomolova, Kučka Stěpánek (2012). Macromol. Rapid Commun.33, 16831689]. It was shown that the presence of the thermosensitive F127 triblock copolymer in solution reduces nanoparticle size and polydispersity. This article focuses on a determination of the internal structure and solution properties of the nanoparticles in the temperature range from 288 to 312 K. Here, it is demonstrated that below the cloud point temperature (CPT) the polyoxazolines and F127 form complexes that co-exist in solution with single F127 molecules and large aggregates. When the temperature is raised above the CPT, nanoparticles composed of polyoxazolines and F127 are predominant in solution. These nanoparticles could be described by a spherical shell model. It was found that the molar weight and hydrophobicity of the polymer do not influence the size of the outer radius and only slightly change the inner radius of the nanoparticles. At the same time, molar weight and hydrophobicity did affect the process of nanoparticle formation. In conclusion, poly(2-oxazoline) molecules are fully incorporated inside of F127 micelles, and this result is very promising for the successful application of such systems in radionuclide delivery.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 18
DOI: 10.1107/S0021889813027064
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“Cocatalyzing Pt/PtO phase-junction nanodots on hierarchically porous TiO2 for highly enhanced photocatalytic hydrogen production”. Ren X-N, Hu Z-Y, Jin J, Wu L, Wang C, Liu J, Liu F, Wu M, Li Y, Van Tendeloo G, Su B-L, ACS applied materials and interfaces 9, 29687 (2017). http://doi.org/10.1021/ACSAMI.7B07226
Abstract: Phase-junctions. between a cocatalyst and its semiconductor host are quite effective to enhance the photo catalytic activity and are widely studied, while reports on the phase-juncted cocatalyst are still rare. In this work, we report the deposition of the Pt/PtO phase-juncted nanodots as cocatalyst via NaOH modification of an interconnected meso-macroporous TiO2 network with high surface area and inner-particle mesopores to enhance the performance of photocatalytic H-2 production. Our results show that NaOH modification can largely influence Pt/PtO phase-juncted nanodot formation and dispersity. Compared to the TiO2 nano particles, the hierarchically meso-macroporous TiO2 network containing 0.18 wt % Pt/PtO phase-juneted cocatalyst demonstrates a highest photocatalytic H-2 rate of 13 mmol g(-1) h(-1) under simulated solar light, and possesses a stable cycling activity without obvious decrease after five cycles. Such high H-2 production performance can be attributed to both the phase-juncted Pt/PtO providing more active sites while PtO suppresses the undesirable hydrogen back reaction, and the special hierarchically porous TiO2 network with inner-particle mesopores presenting short diffusion path lengths for photogenerated electrons and enhanced light harvesting efficiency. This work suggests that Pt/PtO phase-juncted cocatalyst on hierarchically porous TiO2 nanostructures is a promising strategy for advanced photocatalytic H-2 production.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 7.504
Times cited: 18
DOI: 10.1021/ACSAMI.7B07226
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“UiO-66-(SH)2 as stable, selective and regenerable adsorbent for the removal of mercury from water under environmentally-relevant conditions”. Leus K, Perez JPH, Folens K, Meledina M, Van Tendeloo G, Du Laing G, Van Der Voort P, Faraday discussions 201, 145 (2017). http://doi.org/10.1039/C7FD00012J
Abstract: The dithiol functionalized UiO-66-(SH)(2) is developed as an efficient adsorbent for the removal of mercury in aqueous media. Important parameters for the application of MOFs in real-life circumstances include: stability and recyclability of the adsorbents, selectivity for the targeted Hg species in the presence of much higher concentrations of interfering species, and ability to purify wastewater below international environmental limits within a short time. We show that UiO-66-(SH)(2) meets all these criteria.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.588
Times cited: 18
DOI: 10.1039/C7FD00012J
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“Magnetic field dependence of electronic properties of MoS2 quantum dots with different edges”. Chen Q, Li LL, Peeters FM, Physical review B 97, 085437 (2018). http://doi.org/10.1103/PHYSREVB.97.085437
Abstract: Using the tight-binding approach, we investigate the energy spectrum of square, triangular, and hexagonal MoS2 quantum dots (QDs) in the presence of a perpendicular magnetic field. Novel edge states emerge in MoS2 QDs, which are distributed over the whole edge which we call ring states. The ring states are robust in the presence of spin-orbit coupling (SOC). The corresponding energy levels of the ring states oscillate as a function of the perpendicular magnetic field which are related to Aharonov-Bohm oscillations. Oscillations in the magnetic field dependence of the energy levels and the peaks in the magneto-optical spectrum emerge (disappear) as the ring states are formed (collapsed). The period and the amplitude of the oscillation decrease with the size of the MoS2 QDs.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 18
DOI: 10.1103/PHYSREVB.97.085437
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“Interfacial dielectric layer as an origin of polarization fatigue in ferroelectric capacitors”. Do MT, Gauquelin N, Nguyen MD, Wang J, Verbeeck J, Blom F, Koster G, Houwman EP, Rijnders G, Scientific Reports 10, 7310 (2020). http://doi.org/10.1038/s41598-020-64451-0
Abstract: Origins of polarization fatigue in ferroelectric capacitors under electric field cycling still remain unclear. Here, we experimentally identify origins of polarization fatigue in ferroelectric PbZr0.52Ti0.48O3 (PZT) thin-film capacitors by investigating their fatigue behaviours and interface structures. The PZT layers are epitaxially grown on SrRuO3-buffered SrTiO3 substrates by a pulsed laser deposition (PLD), and the capacitor top-electrodes are various, including SrRuO3 (SRO) made by in-situ PLD, Pt by in-situ PLD (Pt-inPLD) and ex-situ sputtering (Pt-sputtered). We found that fatigue behaviour of the capacitor is directly related to the top-electrode/PZT interface structure. The Pt-sputtered/PZT/SRO capacitor has a thin defective layer at the top interface and shows early fatigue while the Pt-inPLD/PZT/SRO and SRO/PZT/SRO capacitor have clean top-interfaces and show much more fatigue resistance. The defective dielectric layer at the Pt-sputtered/PZT interface mainly contains carbon contaminants, which form during the capacitor ex-situ fabrication. Removal of this dielectric layer significantly delays the fatigue onset. Our results clearly indicate that dielectric layer at ferroelectric capacitor interfaces is the main origin of polarization fatigue, as previously proposed in the charge injection model.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 4.6
Times cited: 18
DOI: 10.1038/s41598-020-64451-0
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“A patent landscape analysis for organic photovoltaic solar cells : identifying the technology's development phase”. Lizin S, Leroy J, Delvenne C, Dijk M, De Schepper E, Van Passel S, Renewable Energy 57, 5 (2013). http://doi.org/10.1016/J.RENENE.2013.01.027
Abstract: Organic photovoltaics (OPV) have developed into a vast research area. Progress in various directions has made it difficult to monitor the technology's precise development state. We offer a patent landscape analysis over all OPV devices, their substrates and encapsulation materials to provide an overview of patenting activity from a historical, organizational, geographical and technological point of view. Such an exercise is instrumental for private companies and research institutes aiming at both internal or external technology creation. We discuss our findings in the context of the Industrial Life Cycle model and find OPV still residing in the fluid technology development phase. Technology development is still following an exponential growth path, with the majority of patents coming from the Asian continent and in general private companies. For devices, the main technological focus can be traced back to the “H01L-031” international patent classification (IPC) main group. For the queried substrates, the most attention has gone to glass, but paper and textile have drawn significant interest too. Finally, encapsulation is found to be a less mature research field given the smaller number of patent families. The latter shows that the technology has not matured to the level where processing is carried out on a commercial scale. (C) 2013 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Engineering Management (ENM)
Impact Factor: 4.357
Times cited: 18
DOI: 10.1016/J.RENENE.2013.01.027
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“Optical spectroscopy as a rapid and low-cost tool for the first-line analysis of glass artefacts : a step-by-step plan for Roman green glass”. Meulebroeck W, Cosyns P, Baert K, Wouters H, Cagno S, Janssens K, Terryn H, Nys K, Thienpont H, Journal of archaeological science 38, 2387 (2011). http://doi.org/10.1016/J.JAS.2011.04.023
Abstract: Archaeometric research on glass artefacts is continuously evolving and is converging towards a multidisciplinary research domain where different types of techniques are applied depending on the questions asked and the circumstances involved. The technique described in this work is optical spectroscopy. The benefit of this technique being the possibility of building up a knowledge database for a large amount of material in a relatively short period of time and with a relatively limited budget. This is of particular interest for the investigation of extensive and/or unexplored glass collections where a first-line analysis of artefacts could facilitate the selection of material needing further and more detailed examination. This publication explores the extent to which optical spectroscopy can be used for a first-line analysis of green coloured glass artefacts from the Roman period. It is shown that the colour coordinates calculated from the measured transmission spectrum could reveal information about the fragment under study. In particular it is shown that 1) based on the position of the calculated colour values on the colour diagram (CIE1931) one could easily know whether the artefact was coloured using only iron or if copper oxides were also present. In the case of the artefact owing its colour solely to the presence of iron, the distance between the measured colour values and the colour diagrams white point can roughly indicate the iron concentration of the sample; 2) artefacts that were fabricated under similar furnace conditions can also be identified on the colour diagram; 3) samples with identical compositions and fabrication conditions but with different sample thickness, gave rise to a variation in the colour coordinates, thus allowing optical spectroscopy to help identify fragments which might belong to the same object.
Keywords: A1 Journal article; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 2.602
Times cited: 18
DOI: 10.1016/J.JAS.2011.04.023
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“Comparing frontier methods for economic-environmental trade-off analysis”. Van Meensel J, Lauwers L, Van Huylenbroeck G, Van Passel S, European Journal Of Operational Research 207, 1027 (2010). http://doi.org/10.1016/J.EJOR.2010.05.026
Abstract: This paper uses a mechanistic frontier approach as a reference to evaluate the ability of conventional parametric (SFA) and non-parametric (DEA) frontier approaches for analyzing economicenvironmental trade-offs. Conventional frontier approaches are environmentally adjusted through incorporating the materials balance principle. The analysis is worked out for the Flemish pig finishing case, which is both representative and didactic. Results show that, on average, SFA and DEA yield adequate economicenvironmental trade-offs. Both methods are good estimators for technical efficiency. Cost allocative and environmental allocative efficiency scores are less robust, due to the well-known methodological advantages and disadvantages of SFA and DEA. For particular firms, SFA, DEA and the mechanistic approach may yield different economicenvironmental trade-offs. One has therefore to be careful when using conventional frontier approaches for firm-specific decision support. The mechanistic approach allows for optimizing performances per average present finisher, which is the production unit in pig finishing. Conventional frontier methods do not allow for this optimization since the number of average present finishers varies along the production functions. Since the mechanistic production function is based on underlying growth, feed uptake and mortality functions, additional firm-specific indicators can also be calculated at each point of the production function.
Keywords: A1 Journal article; Economics
Impact Factor: 3.297
Times cited: 18
DOI: 10.1016/J.EJOR.2010.05.026
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“Rembrandt's 'Saul and David' (c. 1652) : use of multiple types of smalt evidenced by means of non-destructive imaging”. Janssens K, van der Snickt G, Alfeld M, Noble P, van Loon A, Delaney J, Conover D, Zeibel J, Dik J, Microchemical journal 126, 515 (2016). http://doi.org/10.1016/J.MICROC.2016.01.013
Abstract: The painting Saul and David, considered to date from c. 1652 and previously attributed to Rembrandt van Rijn and/or his studio, is a complex work of art that has been recently subjected to intensive investigation and conservation treatment. The goal of the research was to give insight into the painting's physical construction and condition in preparation for conservation treatment. It was also anticipated that analysis would shed light on authenticity questions and Rembrandt's role in the creation of the painting. The painting depicts the Old Testament figures of King Saul and David. At left is Saul, seated, holding a spear and wiping a tear from his eye with a curtain. David kneels before him at the right playing his harp. In the past, the large sections with the life-size figures were cut apart and later reassembled. A third piece of canvas was added to replace a missing piece of canvas above the head of David. As part of the investigation into the authenticity of the curtain area, a number of paint micro samples were examined with LM and SEM-EDX. Given that the earth, smalt and lake pigments used in the painting could not be imaged with traditional imaging techniques, the entire painting was also examined with state of the art non-destructive imaging techniques. Special attention was devoted to the presence of cobalt-containing materials, specifically the blue glass pigment smalt considered characteristic for the late Rembrandt. A combination of quantitative electron microprobe analysis and macroscopic X-ray fluorescence scanning revealed that three types of cobalt-containing materials are present in the painting. The first type is a cobalt drier that was found in the overpaint used to cover up the canvas inset and the joins that were added in the 19th century. The other two Co-containing materials are part of the original paint used by Rembrandt and comprise two varieties of smalt, a K-rich glass pigment that derives its gray-blue color by doping with Co-ions. Smalt paint with a higher Ni content (NiO:CoO ratio of around 1:4) was used to depict the blue stripes in Saul's colorful turban, while smalt with a lower Ni content was employed (NiO:CoO ratio of around 1:5) for the broad expanses of Saul's garments. The presence of two types of smalt not only supports the recent re-attribution of the painting to Rembrandt, but also that the picture was painted in two phases. Saul's dark red garment is painted in a rough, “loose” manner and the now discolored smalt-rich layer was found to have been partially removed during a past restoration treatment/s. In contrast, the blue-green smalt in the turban is much better preserved and provides a colorful accent. While the use of different types of smalt in a Rembrandt painting has been previously identified using quantitative EDX analysis of paint cross-sections, to the best of our knowledge this is the first time such a distinction has been observed in a 17th-century painting using non-destructive imaging techniques. In addition to the XRF-based non-invasive elemental mapping, hyperspectral imaging in the visual to near-infrared (VNIR) region was also carried out. (C) 2016 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 3.034
Times cited: 18
DOI: 10.1016/J.MICROC.2016.01.013
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“Deeply colored and black-appearing Roman glass : a continued research”. Cagno S, Cosyns P, Izmer A, Vanhaecke F, Nys K, Janssens K, Journal of archaeological science 42, 128 (2014). http://doi.org/10.1016/J.JAS.2013.11.003
Abstract: In the context of archaeological and historical assessment of Roman black-appearing glass, the chemical and physical characterization of a large collection of samples originating from various areas of the Roman Empire has been gathered over the past years to (i) verify whether a minor segment of the overall Roman glass production can help in determining possible diachronic changes in Roman imperial glass production (1st century AD – 5th century AD) and (ii) reveal regional compositional differences. In this paper, the latest results on the chemical composition of an additional 44 black-appearing Roman glass samples are presented, together with general conclusions based upon the entire compositional dataset of over 400 analyzed black glass samples. The results show that the Roman black glass is obtained through several glass compositions with a specific chronological, geographical and typological distribution. (C) 2013 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Philosophy; History; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 2.602
Times cited: 18
DOI: 10.1016/J.JAS.2013.11.003
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“Control of C3N4 and C4N3 carbon nitride nanosheets' electronic and magnetic properties through embedded atoms”. Bafekry A, Stampfl C, Akgenc B, Ghergherehchi M, Physical Chemistry Chemical Physics 22, 2249 (2020). http://doi.org/10.1039/C9CP06031F
Abstract: In the present work, the effect of various embedded atom impurities on tuning electronic and magnetic properties of C3N4 and C4N3 nanosheets have been studied using first-principles calculations. Our calculations show that C3N4 is a semiconductor and it exhibits extraordinary electronic properties such as dilute-magnetic semiconductor (with H, F, Cl, Be, V, Fe and Co); metal (with N, P, Mg and Ca), half-metal (with Li, Na, K, Al, Sc, Cr, Mn, and Cu) and semiconductor (with O, S, B, C, Si, Ti, Ni and Zn) with the band gaps in the range of 0.3-2.0 eV depending on the species of embedded atom. The calculated electronic properties reveal that C4N3 is a half-metal and it retains half-metallic character with embedded H, O, S, F, B, N, P, Be, Mg, Al, Sc, V, Fe, Ni and Zn atoms. The substitution of Cl, C, Cr and Mn atoms create ferromagnetic-metal character in the C4N3 nanosheet, embedded Co and Cu atoms exhibit a dilute-magnetic semiconductor nature, and embedded Ti atoms result in the system becoming a semiconductor. Therefore, our results reveal the fact that the band gap and magnetism can be modified or induced by various atom impurities, thus, offering effective possibilities to tune the electronic and magnetic properties of C3N4 and C4N3 nanosheets.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.3
Times cited: 18
DOI: 10.1039/C9CP06031F
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“Strain-engineered metal-to-insulator transition and orbital polarization in nickelate superlattices integrated on silicon”. Chen B, Gauquelin N, Jannis D, Cunha DM, Halisdemir U, Piamonteze C, Lee JH, Belhadi J, Eltes F, Abel S, Jovanovic Z, Spreitzer M, Fompeyrine J, Verbeeck J, Bibes M, Huijben M, Rijnders G, Koster G, Advanced Materials , 2004995 (2020). http://doi.org/10.1002/ADMA.202004995
Abstract: Epitaxial growth of SrTiO3 (STO) on silicon greatly accelerates the monolithic integration of multifunctional oxides into the mainstream semiconductor electronics. However, oxide superlattices (SLs), the birthplace of many exciting discoveries, remain largely unexplored on silicon. In this work, LaNiO3/LaFeO3 SLs are synthesized on STO-buffered silicon (Si/STO) and STO single-crystal substrates, and their electronic properties are compared using dc transport and X-ray absorption spectroscopy. Both sets of SLs show a similar thickness-driven metal-to-insulator transition, albeit with resistivity and transition temperature modified by the different amounts of strain. In particular, the large tensile strain promotes a pronounced Ni 3dx2-y2 orbital polarization for the SL grown on Si/STO, comparable to that reported for LaNiO3 SL epitaxially strained to DyScO3 substrate. Those results illustrate the ability to integrate oxide SLs on silicon with structure and property approaching their counterparts grown on STO single crystal, and also open up new prospects of strain engineering in functional oxides based on the Si platform.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 29.4
Times cited: 18
DOI: 10.1002/ADMA.202004995
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“First-principles investigation of nonmetal doped single-layer BiOBr as a potential photocatalyst with a low recombination rate”. Obeid MM, Stampfl C, Bafekry A, Guan Z, Jappor HR, Nguyen C V, Naseri M, Hoat DM, Hieu NN, Krauklis AE, Tuan V Vu, Gogova D, Physical Chemistry Chemical Physics 22, 15354 (2020). http://doi.org/10.1039/D0CP02007A
Abstract: Nonmetal doping is an effective approach to modify the electronic band structure and enhance the photocatalytic performance of bismuth oxyhalides. Using density functional theory, we systematically examine the fundamental properties of single-layer BiOBr doped with boron (B) and phosphorus (P) atoms. The stability of the doped models is investigated based on the formation energies, where the substitutional doping is found to be energetically more stable under O-rich conditions than under Bi-rich ones. The results showed that substitutional doping of P atoms reduced the bandgap of pristine BiOBr to a greater extent than that of boron substitution. The calculation of the effective masses reveals that B doping can render the electrons and holes of pristine BiOBr lighter and heavier, respectively, resulting in a slower recombination rate of photoexcited electron-hole pairs. Based on the results of HOMO-LUMO calculations, the introduction of B atoms tends to increase the number of photocatalytically active sites. The top of the valence band and the conduction band bottom of the B doped BiOBr monolayer match well with the water redox potentials in an acidic environment. The absorption spectra propose that B(P) doping causes a red-shift. Overall, the results predict that nonmetal-doped BiOBr monolayers have a reduced bandgap, a slow recombination rate, more catalytically active sites, enhanced optical absorption edges, and reduced work functions, which will contribute to superior photocatalytic performance.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.3
Times cited: 18
DOI: 10.1039/D0CP02007A
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“Wigner crystallization in transition metal dichalcogenides : a new approach to correlation energy”. Zarenia M, Neilson D, Partoens B, Peeters FM, Physical review B 95, 115438 (2017). http://doi.org/10.1103/PHYSREVB.95.115438
Abstract: We introduce a new approach for the correlation energy of one- and two-valley two-dimensional electron gas (2DEG) systems. Our approach is based on an interpolation between two limits, a random phase approximation at high densities and a classical approach at low densities which gives excellent agreement with available Quantum Monte Carlo (QMC) calculations. The two-valley 2DEG model is introduced to describe the electron correlations in monolayer transition metal dichalcogenides (TMDs). We study the zero-temperature transition from a Fermi liquid to a quantum Wigner crystal phase in monolayer TMDs. Consistent with QMC, we find that electrons crystallize at r(s) = 31 in one-valley 2DEG. For two valleys, we predict Wigner crystallization at r(s) = 30, implying that valley degeneracy has little effect on the critical r(s), in contrast to an earlier claim.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 18
DOI: 10.1103/PHYSREVB.95.115438
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“Strain and band-mixing effects on the excitonic Aharonov-Bohm effect in In(Ga)As/GaAs ringlike quantum dots”. Arsoski VV, Tadić, MZ, Peeters FM, Physical review : B : condensed matter and materials physics 87, 085314 (2013). http://doi.org/10.1103/PhysRevB.87.085314
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
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 18
DOI: 10.1103/PhysRevB.87.085314
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“Fe-containing magnesium aluminate support for stability and carbon control during methane reforming”. Theofanidis SA, Galvita VV, Poelman H, Dharanipragada NVRA, Longo A, Meledina M, Van Tendeloo G, Detavernier C, Marin GB, ACS catalysis 8, 5983 (2018). http://doi.org/10.1021/ACSCATAL.8B01039
Abstract: We report a MgFexAl2-xO4 synthetic spinel, where x varies from 0 to 0.26, as support for Ni-based catalysts, offering stability and carbon control under various conditions of methane reforming. By incorporation of Fe into a magnesium aluminate spine!, a support is created with redox functionality and high thermal stability, as concluded from temporal analysis of products (TAP) experiments and redox cycling, respectively. A diffusion coefficient of 3 x 10(-17) m(2) s(-1) was estimated for lattice oxygen at 993 K from TAP experiments. X-ray diffraction (XRD) and extended X-ray absorption fine structure (EXAFS) modeling identified that the incorporation of iron occurs as Fe3+ in the octahedral sites of the spinel lattice, replacing aluminum. Simulation of the X-ray absorption near edge structure (XANES) spectrum of the reduced support showed that 60 +/- 10% of iron was reduced from 3+ to 2+ at 1073 K, while there was no formation of metallic iron. A series of Ni/MgFexAl2-xO4 catalysts, where x varies from 0 to 0.26, was synthesized and reduced, yielding a supported Ni-Fe alloy. The evolution of the catalyst structure during H-2 temperature-programmed reduction (TPR) and CO2 temperature-programmed oxidation (TPO) was examined using time-resolved in situ XRD and XANES. During reforming, iron in both the support and alloy keeps control of carbon accumulation, as confirmed by O-2-TPO on the spent catalysts. By fine tuning the amount of Fe in MgFexAl2-xO4, a supported alloy was obtained with a Ni/Fe molar ratio of similar to 10, which was active for reforming and stable. By comparison of the performance of Ni-based catalysts with Fe either incorporated into or deposited onto the support, the location of Fe within the support proved crucial for the stability and carbon mitigation under reforming conditions.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 10.614
Times cited: 18
DOI: 10.1021/ACSCATAL.8B01039
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“Effect of grain boundary on the buckling of graphene nanoribbons”. Neek-Amal M, Peeters FM, Applied physics letters 100, 101905 (2012). http://doi.org/10.1063/1.3692573
Abstract: The buckling of graphene nano-ribbons containing a grain boundary is studied using atomistic simulations where free and supported boundary conditions are invoked. We consider the buckling transition of two kinds of grain boundaries with special symmetry. When graphene contains a large angle grain boundary with theta = 21.8 degrees, the buckling strains are larger than those of perfect graphene when the ribbons with free (supported) boundary condition are subjected to compressive tension parallel (perpendicular) to the grain boundary. This is opposite for the results of theta = 32.2 degrees. The shape of the deformations of the buckled graphene nanoribbons depends on the boundary conditions, the presence of the particular used grain boundaries, and the direction of applied in-plane compressive tension. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3692573]
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.411
Times cited: 18
DOI: 10.1063/1.3692573
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“Optical properties of GaS-Ca(OH)2 bilayer heterostructure”. Torun E, Sahin H, Peeters FM, Physical review B 93, 075111 (2016). http://doi.org/10.1103/PhysRevB.93.075111
Abstract: Finding novel atomically thin heterostructures and understanding their characteristic properties are critical for developing better nanoscale optoelectronic devices. In this study, we investigate the electronic and optical properties of a GaS-Ca(OH)(2) heterostructure using first-principle calculations. The band gap of the GaS-Ca(OH)(2) heterostructure is significantly reduced when compared to those of the isolated constituent layers. Our calculations showthat the GaS-Ca(OH)(2) heterostructure is a type-II heterojunction which can be used to separate photoinduced charge carriers where electrons are localized in GaS and holes in the Ca(OH)(2) layer. This leads to spatially indirect excitons which are important for solar energy and optoelectronic applications due to their long lifetime. By solving the Bethe-Salpeter equation on top of a single shot GW calculation (G(0)W(0)), the dielectric function and optical oscillator strength of the constituent monolayers and the heterostructure are obtained. The oscillator strength of the optical transition for the GaS monolayer is an order of magnitude larger than the Ca(OH)(2) monolayer. We also found that the calculated optical spectra of different stacking types of the heterostructure show dissimilarities, although their electronic structures are rather similar. This prediction can be used to determine the stacking type of ultrathin heterostructures.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 18
DOI: 10.1103/PhysRevB.93.075111
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“Electron energy and temperature relaxation in graphene on a piezoelectric substrate”. Zhang SH, Xu W, Peeters FM, Badalyan SM, Physical review : B : condensed matter and materials physics 89, 195409 (2014). http://doi.org/10.1103/PhysRevB.89.195409
Abstract: We study the energy and temperature relaxation of electrons in graphene on a piezoelectric substrate. Scattering from the combined potential of extrinsic piezoelectric surface acoustical (PA) phonons of the substrate and intrinsic deformation acoustical phonons of graphene is considered for a (non) degenerate gas of Dirac fermions. It is shown that in the regime of low energies or temperatures the PA phonons dominate the relaxation and change qualitatively its character. This prediction is relevant for quantum metrology and electronic applications using graphene devices and suggests an experimental setup for probing electron-phonon coupling in graphene.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 18
DOI: 10.1103/PhysRevB.89.195409
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“Vortices induced in a superconducting loop by asymmetric kinetic inductance and their detection in transport measurements”. Berdiyorov GR, Milošević, MV, Peeters FM, Physical review : B : condensed matter and materials physics 81, 144511 (2010). http://doi.org/10.1103/PhysRevB.81.144511
Abstract: Using time-dependent Ginzburg-Landau theory, we study the dynamic properties of a rectangular superconducting loop, which are found to depend on the position of the current leads. For asymmetric positioning of the leads, different kinetic inductance of the two paths for injected electric current leads to different critical conditions in the two branches. System self-regulates by allowing vortex entry, as vortex currents bring equilibration between the two current flows and the conventional resistive state can be realized. We also demonstrate that individual vortex entry in the loop can be detected by measuring the voltage between normal-metal leads, for applied currents comparable in magnitude to the screening currents.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 18
DOI: 10.1103/PhysRevB.81.144511
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“Self-assembly of Janus particles into helices with tunable pitch”. Sobrino Fernandez M, Misko VR, Peeters FM, Physical review : E : statistical, nonlinear, and soft matter physics 92, 042309 (2015). http://doi.org/10.1103/PhysRevE.92.042309
Abstract: Janus particles present an important class of building blocks for directional assembly. These are compartmentalized colloids with two different hemispheres. In this work we consider a three-dimensional model of Janus spheres that contain one hydrophobic and one charged hemisphere. Using molecular dynamics simulations, we study the morphology of these particles when confined in a channel-like environment. The interplay between the attractive and repulsive forces on each particle gives rise to a rich phase space where the relative orientation of each particle plays a dominant role in the formation of large-scale clusters. The interest in this system is primarily due to the fact that it could give a better understanding of the mechanisms of the formation of polar membranes. A variety of ordered membranelike morphologies is found consisting of single and multiple connected chain configurations. The helicity of these chains can be chosen by simply changing the salt concentration of the solution. Special attention is given to the formation of Bernal spirals. These helices are composed of regular tetrahedra and are known to exhibit nontrivial translational and rotational symmetry.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.366
Times cited: 18
DOI: 10.1103/PhysRevE.92.042309
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“The magnetic, electronic, and light-induced topological properties in two-dimensional hexagonal FeX₂, (X=Cl, Br, I) monolayers”. Kong X, Li L, Liang L, Peeters FM, Liu X-J, Applied Physics Letters 116, 192404 (2020). http://doi.org/10.1063/5.0006446
Abstract: Using Floquet-Bloch theory, we propose to realize chiral topological phases in two-dimensional (2D) hexagonal FeX2 (X=Cl, Br, I) monolayers under irradiation of circularly polarized light. Such 2D FeX2 monolayers are predicted to be dynamically stable and exhibit both ferromagnetic and semiconducting properties. To capture the full topological physics of the magnetic semiconductor under periodic driving, we adopt ab initio Wannier-based tight-binding methods for the Floquet-Bloch bands, with the light-induced bandgap closings and openings being obtained as the light field strength increases. The calculations of slabs with open boundaries show the existence of chiral edge states. Interestingly, the topological transitions with branches of chiral edge states changing from zero to one and from one to two by tuning the light amplitude are obtained, showing that the topological Floquet phase of high Chern number can be induced in the present Floquet-Bloch systems. Published under license by AIP Publishing.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 4
Times cited: 18
DOI: 10.1063/5.0006446
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