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“Spin-orbit-interaction induced singularity of the charge density relaxation propagator”. Badalyan SM, Matos-Abiague A, Fabian J, Vignale G, Peeters FM, Physical review : B : condensed matter and materials physics 88, 195402 (2013). http://doi.org/10.1103/PhysRevB.88.195402
Abstract: The charge density relaxation propagator of a two-dimensional electron system, which is the slope of the imaginary part of the polarization function, exhibits singularities for bosonic momenta having the order of the spin-orbit momentum and depending on the momentum orientation. We have provided an intuitive understanding for this nonanalytic behavior in terms of the interchirality subband electronic transitions, induced by the combined action of Bychkov-Rashba (BR) and Dresselhaus (D) spin-orbit coupling. It is shown that the regular behavior of the relaxation propagator is recovered in the presence of only one BR or D spin-orbit field or for spin-orbit interaction with equal BR and D coupling strengths. This creates a new possibility to influence carrier relaxation properties by means of an applied electric field.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 2
DOI: 10.1103/PhysRevB.88.195402
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“Spin-torque effects in metallic magnetic multilayers in the ballistic regime”. Krstajić, PM, Keller M, Peeters FM, Physical review : B : condensed matter and materials physics 77, 174428 (2008). http://doi.org/10.1103/PhysRevB.77.174428
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 2
DOI: 10.1103/PhysRevB.77.174428
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“Stabilization of mercury-based superconductors by foreign cations”. Raveau B, Michel C, Hervieu M, Van Tendeloo G, Maignan A, Annales de chimie (1914)
T2 –, 4th North-African Materials Science Symposium (JMSM 94), NOV 23-24, 1994, CASABLANCA, MOROCCO 19, 487 (1994)
Abstract: The recently discovered superconducting mercury-based cuprates HgBa2Can-1CunO2n+2+delta have proved difficult to synthesize as single phases and are sensitive to environment (CO2, moisture). The present paper gives an overview of new series mercury based superconductors, whose stabilisation is based on the fact that a foreign cation with a higher valency than Hg(II) must be introduced in the mercury layers, in order to fill up partially the oxygen vacancies of these layers. By this method, several new series of superconductors involving strontium instead of barium with critical temperatures ranging from 27 K to 95 K have been isolated : Hg0.5Bi0.5Sr2-xLaxCuO4+delta, Hg(0.5)Bi(0.5)Sr(2)Ca(1-x)R(x)Cu(2)O(6+delta) (R Y, Nd, Pr), Pb0.7Hg0.3Sr2-xLaxCuO4+delta, Pb(0.7)Hg(0.3)Sr(2)Ca(1-x)R(x)Cu(2)O(6+delta) (R = Y, Nd) Hg(1-x)Pr(x)Sr(2)A(1-x')Pr(x') Cu2O6+delta (A = Sr, Ca), Pb0.7Hg0.3Sr2Cu2CO3O7 and Hg1-xCrxSr2CuO4+delta. The behaviour of the praseodymium cuprates that exhibit a rather sharp transition and reach a Tc of 85 K is especially discussed. A method to synthesize new ''Ba-Hg'' superconducting cuprates with the 1212 structure at normal pressure with a Tc up to 110 K is also presented.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 2
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“Structural studies on superconducting materials and fullerites by electron microscopy”. Van Tendeloo G, Amelinckx S, Advanced materials 5, 620 (1993). http://doi.org/10.1002/adma.19930050904
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 17.493
Times cited: 2
DOI: 10.1002/adma.19930050904
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“Structure and magnetic properties of a new anion-deficient perovskite Pb2Ba2BiFe4ScO13 with crystallographic shear structure”. Batuk M, Tyablikov OA, Tsirlin AA, Kazakov SM, Rozova MG, Pokholok KV, Filimonov DS, Antipov EV, Abakumov AM, Hadermann J, Materials research bulletin 48, 3459 (2013). http://doi.org/10.1016/j.materresbull.2013.05.028
Abstract: Pb2Ba2BiFe4ScO13, a new n = 5 member of the oxygen-deficient perovskite-based A(n)B(n)O(3n-2) homologous series, was synthesized using a solid-state method. The crystal structure of Pb2Ba2BiFe4ScO13 was investigated by a combination of synchrotron X-ray powder diffraction, electron diffraction, high-angle annular dark-field scanning transmission electron microscopy and Mossbauer spectroscopy. At 900 K, it crystallizes in the Ammm space group with the unit cell parameters a = 5.8459(1) angstrom, b = 4.0426(1) angstrom, and c=27.3435(1) angstrom. In the Pb2Ba2BiFe4ScO13 structure, quasi-two-dimensional perovskite blocks are periodically interleaved with 1/2[1 1 0] ((1) over bar 0 1)(p) crystallographic shear (CS) planes. At the CS planes, the corner-sharing FeO6 octahedra are transformed into chains of edge-sharing FeO5 distorted tetragonal pyramids. B-positions of the perovskite blocks between the CS planes are jointly occupied by Fe3+ and Sc3+. The chains of the FeO5 pyramids and (Fe,Sc)O-6 octahedra delimit six-sided tunnels that are occupied by double columns of cations with a lone electron pair (Pb2+). The remaining A-cations (Bi3+, Ba2+) occupy positions in the perovskite block. According to the magnetic susceptibility measurements, Pb2Ba2BiFe4ScO13 is antiferromagnetically ordered below T-N approximate to 350 K. (C) 2013 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.446
Times cited: 2
DOI: 10.1016/j.materresbull.2013.05.028
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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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“Temporary cooling of quasiparticles and delay in voltage response of superconducting bridges after abruptly switching on the supercritical current”. Vodolazov DY, Peeters FM, Physical review : B : condensed matter and materials physics 90, 094504 (2014). http://doi.org/10.1103/PhysRevB.90.094504
Abstract: We revisit the problem of the dynamic response of a superconducting bridge after abruptly switching on the supercritical current. In contrast to previous theoretical works we take into account spatial gradients and use both the local temperature approach and the kinetic equation for the distribution function of quasiparticles. We find that the temperature dependence of the finite delay time t(d) in the voltage response is model dependent and relatively large t(d) is connected with temporary cooling of quasiparticles during decay of superconducting order parameter vertical bar Delta vertical bar in time. It turns out that the presence of even small inhomogeneities in the bridge or finite length of the homogenous bridge favors a local suppression of vertical bar Delta vertical bar during the dynamic response. It results in a decrease of the delay time, in comparison with the spatially uniform model, due to the diffusion of nonequilibrium quasiparticles from the region with locally suppressed vertical bar Delta vertical bar. In the case when the current density is maximal near the edge of a not very wide bridge the delay time is mainly connected with the time needed for the nucleation (entrance) of the first vortex and t(d) could be tuned by a weak external magnetic field. We also find that a short alternating current pulse (sinusoidlike) with zero time average may result in a nonzero time- averaged voltage response where its sign depends on the phase of the ac current.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 2
DOI: 10.1103/PhysRevB.90.094504
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“133Xe(Cs) Mössbauer measurements on Ar, Ne, Kr, Xe, Rb, and Cs inclusions in W and Mo”. Milants K, Hendrickx P, Verheyden J, Barancira T, Deweerd W, Pattyn H, Bukshpan S, Vermeiren F, Van Tendeloo G, Physical review : B : condensed matter and materials physics 55, 2831 (1997)
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 2
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“Thermodynamic properties of the electron gas in multilayer graphene in the presence of a perpendicular magnetic field”. Van Duppen B, Peeters FM, Physical review : B : condensed matter and materials physics 88, 245429 (2013). http://doi.org/10.1103/PhysRevB.88.245429
Abstract: The thermodynamic properties of the electron gas in multilayer graphene depend strongly on the number of layers and the type of stacking. Here we analyze how those properties change when we vary the number of layers for rhombohedral stacked multilayer graphene and compare our results with those from a conventional two-dimensional electron gas. We show that the highly degenerate zero-energy Landau level which is partly filled with electrons and partly with holes has a strong influence on the values of the different thermodynamic quantities.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 2
DOI: 10.1103/PhysRevB.88.245429
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“Vortex detection and quantum transport in mesoscopic graphene Josephson-junction arrays”. Richardson CL, Edkins SD, Berdiyorov GR, Chua CJ, Griffiths JP, Jones GAC, Buitelaar MR, Narayan V, Sfigakis F, Smith CG, Covaci L, Connolly MR;, Physical review : B : condensed matter and materials physics 91, 245418 (2015). http://doi.org/10.1103/PhysRevB.91.245418
Abstract: We investigate mesoscopic Josephson-junction arrays created by patterning superconducting disks on monolayer graphene, concentrating on the high-T/T-c regime of these devices and the phenomena which contribute to the superconducting glass state in diffusive arrays. We observe features in the magnetoconductance at rational fractions of flux quanta per array unit cell, which we attribute to the formation of flux-quantized vortices. The applied fields at which the features occur are well described by Ginzburg-Landau simulations that take into account the number of unit cells in the array. We find that the mean conductance and universal conductance fluctuations are both enhanced below the critical temperature and field of the superconductor, with greater enhancement away from the graphene Dirac point.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 2
DOI: 10.1103/PhysRevB.91.245418
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“Vortex quantum tunneling versus thermal activation in ultrathin superconducting nanoislands”. Pogosov WV, Misko VR, Physical review : B : condensed matter and materials physics 85, 224508 (2012). http://doi.org/10.1103/PhysRevB.85.224508
Abstract: We consider two possible mechanisms for single-vortex fluctuative entry/exit through the surface barrier in ultrathin superconducting disk-shaped nanoislands made of Pb and consisting of just a few monoatomic layers, which can be fabricated using modern techniques. We estimate tunneling probabilities and establish criteria for the crossover between these two mechanisms depending on magnetic field and system sizes. For the case of vortex entry, quantum tunneling dominates on the major part of the temperature/flux phase diagram. For the case of vortex exit, thermal activation turns out to be more probable. This nontrivial result is due to the subtle balance between the barrier height and width, which determine rates of the thermal activation and quantum tunneling, respectively.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 2
DOI: 10.1103/PhysRevB.85.224508
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“Large CO2 uptake on a monolayer of CaO”. Berdiyorov GR, Neek-Amal M, Hussein IA, Madjet ME, Peeters FM, Journal of materials chemistry A : materials for energy and sustainability 5, 2110 (2017). http://doi.org/10.1039/C6TA08810D
Abstract: Density functional theory calculations are used to study gas adsorption properties of a recently synthesized CaO monolayer, which is found to be thermodynamically stable in its buckled form. Due to its topology and strong interaction with the CO2 molecules, this material possesses a remarkably high CO2 uptake capacity (similar to 0.4 g CO2 per g adsorbent). The CaO + CO2 system shows excellent thermal stability (up to 1000 K). Moreover, the material is highly selective towards CO2 against other major greenhouse gases such as CH4 and N2O. These advantages make this material a very promising candidate for CO2 capture and storage applications.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 8.867
Times cited: 2
DOI: 10.1039/C6TA08810D
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“Size-Induced Switching of Nanowire Growth Direction: a New Approach Toward Kinked Nanostructures”. Shen Y, Lebedev OI, Turner S, Van Tendeloo G, Song X, Yu X, Wang Q, Chen H, Dayeh SA, Wu T, Advanced functional materials 26, 3687 (2016). http://doi.org/10.1002/ADFM.201600142
Abstract: Exploring self-assembled nanostructures with controllable architectures has been a central theme in nanoscience and nanotechnology because of the tantalizing perspective of directly integrating such bottom-up nanostructures into functional devices. Here, the growth of kinked single-crystal In2O3 nanostructures consisting of a nanocone base and a nanowire tip with an epitaxial and defect-free transition is demonstrated for the first time. By tailoring the growth conditions, a reliable switching of the growth direction from [111] to [110] or [112] is observed when the Au catalyst nanoparticles at the apexes of the nanocones shrink below approximate to 100 nm. The natural formation of kinked nanoarchitectures at constant growth pressures is related to the size-dependent free energy that changes for different orientations of the nanowires. The results suggest that the mechanism of forming such kinked nanocone-nanowire nanostructures in well-controlled growth environment may be universal for a wide range of functional materials.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 12.124
Times cited: 2
DOI: 10.1002/ADFM.201600142
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“Stabilities of bimetallic nanoparticles for chirality-selective carbon nanotube growth and the effect of carbon interstitials”. Vets C, Neyts EC, The journal of physical chemistry: C : nanomaterials and interfaces 121, 15430 (2017). http://doi.org/10.1021/ACS.JPCC.7B02880
Abstract: Bimetallic nanoparticles play a crucial role in various applications. A better understanding of their properties would facilitate these applications and possibly even enable chirality-specific growth of carbon nanotubes (CNTs). We here examine the stabilities of NiFe, NiGa, and FeGa nanoparticles and the effect of carbon dissolved in NiFe nanoparticles through density functional theory (DFT) calculations and Born Oppenheimer molecular dynamics (BOMD) simulations. We establish that nanoparticles with more Fe in the core and more Ga on the surface are more stable and compare these results with well-known properties such as surface energy and atom size. Furthermore, we find that the nanoparticles become more stable with increasing carbon content, both at 0 K and at 700 K. These results provide a basis for further research into the chirality-specific growth of CNT's.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.536
Times cited: 2
DOI: 10.1021/ACS.JPCC.7B02880
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“Structural characterization of SnS crystals formed by chemical vapour deposition”. Mehta AN, Zhang H, Dabral A, Richard O, Favia P, Bender H, Delabie A, Caymax M, Houssa M, Pourtois G, Vandervorst W, Journal of microscopy
T2 –, 20th International Conference on Microscopy of Semiconducting Materials, (MSM), APR 09-13, 2017, Univ Oxford, Univ Oxford, Oxford, ENGLAND 268, 276 (2017). http://doi.org/10.1111/JMI.12652
Abstract: <script type='text/javascript'>document.write(unpmarked('The crystal and defect structure of SnS crystals grown using chemical vapour deposition for application in electronic devices are investigated. The structural analysis shows the presence of two distinct crystal morphologies, that is thin flakes with lateral sizes up to 50 m and nanometer scale thickness, and much thicker but smaller crystallites. Both show similar Raman response associated with SnS. The structural analysis with transmission electron microscopy shows that the flakes are single crystals of -SnS with [010] normal to the substrate. Parallel with the surface of the flakes, lamellae with varying thickness of a new SnS phase are observed. High-resolution transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), first-principles simulations (DFT) and nanobeam diffraction (NBD) techniques are employed to characterise this phase in detail. DFT results suggest that the phase is a strain stabilised \u0027 one grown epitaxially on the -SnS crystals. TEM analysis shows that the crystallites are also -SnS with generally the [010] direction orthogonal to the substrate. Contrary to the flakes the crystallites consist of two to four grains which are tilted up to 15 degrees relative to the substrate. The various grain boundary structures and twin relations are discussed. Under high-dose electron irradiation, the SnS structure is reduced and -Sn formed. It is shown that this damage only occurs for SnS in direct contact with SiO2. Lay description SnS is a p-type semiconductor, which has attracted significant interest for electronic devices due to its unique properties, low-toxicity and abundance of Sn in nature. Although in the past it has been most extensively studied as the absorber material in solar cells, it has recently garnered interest for application as a p-type two-dimensional semiconductor in nanoelectronic devices due to its anisotropic layered structure similar to the better known phosphorene. Tin sulphide can take the form of several phases and the electronic properties of the material depend strongly on its crystal structure. It is therefore crucial to study the crystal structure of the material in order to predict the electronic properties and gain insight into the growth mechanism. In this work, SnS crystals deposited using a chemical vapour deposition technique are investigated extensively for their crystal and defect structure using transmission electron microscopy (TEM) and related techniques. We find the presence of two distinct crystal morphologies, that is thin flakes with lateral sizes up to 50 m and nm scale thickness, and much thicker but smaller crystallites. The flakes are single crystals of -SnS and contain lamellae with varying thickness of a different phase which appear to be -SnS at first glance. High-resolution scanning transmission electron microscopy is used to characterise these lamellae where the annular bright field (ABF) mode better reveals the position of the sulphur columns. The sulphur columns in the lamellae are found to be shifted relative to the -SnS structure which indicates the formation of a new phase which is a distorted version of the phase which we tentatively refer to as \u0027-SnS. Simulations based on density functional theory (DFT) are used to model the interface and a similar shift of sulphur columns in the -SnS layer is observed which takes place as a result of strong interaction at the interface between the two phases resulting in strain transfer. Nanobeam electron diffraction (NBD) is used to map the lattice mismatch in the thickness of the flakes which reveals good in-plane matching and some expansion out-of-plane in the lamellae. Contrary to the flakes the crystallites are made solely of -SnS and consist of two to four grains which are tilted up to 15 degrees relative to the substrate. The various grain boundary structures and twin relations are discussed. At high electron doses, SnS is reduced to -Sn, however the damage occurs only for SnS in direct contact with SiO2.'));
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.692
Times cited: 2
DOI: 10.1111/JMI.12652
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“Formation of a conducting LaAlO3/SrTiO3 interface studied by low-energy electron reflection during growth”. van der Torren AJH, Liao Z, Xu C, Gauquelin N, Yin C, Aarts J, van der Molen SJ, Physical Review Materials 1, 075001 (2017). http://doi.org/10.1103/PhysRevMaterials.1.075001
Abstract: The two-dimensional electron gas occurring between the band insulators SrTiO 3 and LaAlO 3 continues to attract considerable interest, due to the possibility of dynamic control over the carrier density, and the ensuing phenomena such as magnetism and superconductivity. The formation of this conducting interface is sensitive to the growth conditions, but despite numerous investigations, there are still questions about the details of the physics involved. In particular, not much is known about the electronic structure of the growing LaAlO 3 layer at the growth temperature (around 800 ◦ C) in oxygen (pressure around 5 × 10 −5 mbar), since analysis techniques at these conditions are not readily available. We developed a pulsed laser deposition system inside a low-energy electron microscope in order to study this issue. The setup allows for layer-by-layer growth control and in-situ measurements of the angle-dependent electron reflection intensity, which can be used as a fingerprint of the electronic structure of the surface layers during growth. By using different substrate terminations and growth conditions we observe two families of reflectivity maps, which we can connect either to samples with an AlO 2 -rich surface and a conducting interface; or to samples with a LaO-rich surface and an insulating interface. Our observations emphasize that substrate termination and stoichiometry determine the electronic structure of the growing layer, and thereby the conductance of the interface.
Keywords: A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ;
Times cited: 2
DOI: 10.1103/PhysRevMaterials.1.075001
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“Synthesis of high-oxidation Y-Ba-Cu-O phases in superoxygenated thin films”. Zhang H, Gauquelin N, McMahon C, Hawthorn DG, Botton GA, Wei JYT, Physical review materials 2, 033803 (2018). http://doi.org/10.1103/PHYSREVMATERIALS.2.033803
Abstract: It is known that solid-state reaction in high-pressure oxygen can stabilize high-oxidation phases of Y-Ba-Cu-O superconductors in powder form. We extend this superoxygenation concept of synthesis to thin films which, due to their large surface-to-volume ratio, are more reactive thermodynamically. Epitaxial thin films of YBa2Cu3O7-delta grown by pulsed laser deposition are annealed at up to 700 atm O-2 and 900 degrees C, in conjunction with Cu enrichment by solid-state diffusion. The films show the clear formation of Y2Ba4Cu7O15-delta and Y2Ba4Cu8O16 as well as regions of YBa2Cu5O9-delta and YBa2Cu6O10-delta phases, according to scanning transmission electron microscopy, x-ray diffraction, and x-ray absorption spectroscopy. Similarly annealed YBa2Cu3O7-delta powders show no phase conversion. Our results demonstrate a route of synthesis towards discovering more complex phases of cuprates and other superconducting oxides.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 2
DOI: 10.1103/PHYSREVMATERIALS.2.033803
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“Chemical activity of the peroxide/oxide redox couple : case study of Ba5Ru2O11 in aqueous and organic solvents”. Grimaud A, Iadecola A, Batuk D, Saubanere M, Abakumov AM, Freeland JW, Cabana J, Li H, Doublet M-L, Rousse G, Tarascon J-M, Chemistry of materials 30, 3882 (2018). http://doi.org/10.1021/ACS.CHEMMATER.8B01372
Abstract: The finding that triggering the redox activity of oxygen ions within the lattice of transition metal oxides can boost the performances of materials used in energy storage and conversion devices such as Li-ion batteries or oxygen evolution electrocatalysts has recently spurred intensive and innovative research in the field of energy. While experimental and theoretical efforts have been critical in understanding the role of oxygen nonbonding states in the redox activity of oxygen ions, a clear picture of the redox chemistry of the oxygen species formed upon this oxidation process is still missing. This can be, in part, explained by the complexity in stabilizing and studying these species once electrochemically formed. In this work, we alleviate this difficulty by studying the phase Ba5Ru2O11, which contains peroxide O-2(2-) groups, as oxygen evolution reaction electrocatalyst and Li-ion battery material. Combining physical characterization and electrochemical measurements, we demonstrate that peroxide groups can easily be oxidized at relatively low potential, leading to the formation of gaseous dioxygen and to the instability of the oxide. Furthermore, we demonstrate that, owing to the stabilization at high energy of peroxide, the high-lying energy of the empty sigma* antibonding O-O states limits the reversibility of the electrochemical reactions when the O-2(2-)/O2- redox couple is used as redox center for Li-ion battery materials or as OER redox active sites. Overall, this work suggests that the formation of true peroxide O-2(2-) states are detrimental for transition metal oxides used as OER catalysts and Li-ion battery materials. Rather, oxygen species with O-O bond order lower than 1 would be preferred for these applications.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 2
DOI: 10.1021/ACS.CHEMMATER.8B01372
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“Theoretical and experimental investigation of conjugation of 1,6-hexanedithiol on MoS2”. Gul A, Bacaksiz C, Unsal E, Akbali B, Tomak A, Zareie HM, Sahin H, Materials Research Express 5, 036415 (2018). http://doi.org/10.1088/2053-1591/AAB4A6
Abstract: We report an experimental and theoretical investigation of conjugation of 1,6-Hexaneditihiol (HDT) on MoS2 which is prepared by mixing MoS2 structure and HDT molecules in proper solvent. Raman spectra and the calculated phonon bands reveal that the HDT molecules bind covalently to MoS2. Surface morphology of MoS2/HDTstructure is changed upon conjugation ofHDTon MoS2 and characterized by using Scanning Electron Microscope (SEM). Density Functional Theory (DFT) based calculations show that HOMO-LUMO band gap of HDT is altered after the conjugation and two-S binding (handle-like) configuration is energetically most favorable among three different structures. This study displays that the facile thiol functionalization process of MoS2 is promising strategy for obtaining solution processable MoS2.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.068
Times cited: 2
DOI: 10.1088/2053-1591/AAB4A6
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“Incommensurately modulated structures and luminescence properties of the AgxSm(2-x)/3WO4 (x=0.286, 0.2) scheelites as thermographic phosphors”. Morozov V, Deyneko D, Basoyich O, Khaikina EG, Spassky D, Morozov A, Chernyshev V, Abakumov A, Hadermann J, Chemistry of materials 30, 4788 (2018). http://doi.org/10.1021/ACS.CHEMMATER.8B02029
Abstract: Ag+ for Sm3+ substitution in the scheelite-type AgxSm(2-x)/3 square(1-2x)/3WO4 tungstates has been investigated for its influence on the cation-vacancy ordering and luminescence properties. A solid state method was used to synthesize the x = 0.286 and x = 0.2 compounds, which exhibited (3 + 1)D incommensurately modulated structures in the transmission electron microscopy study. Their structures were refined using high resolution synchrotron powder X-ray diffraction data. Under near-ultraviolet light, both compounds show the characteristic emission lines for (4)G(5/2) -> H-6(J) (J = 5/2, 7/2, 9/2, and 11/2) transitions of the Sm3+ ions in the range 550-720 nm, with the J = 9/2 transition at the similar to 648 nm region being dominant for all photoluminescence spectra. The intensities of the (4)G(5/2) -> H-6(9/2) and (4)G(5/2) -> H-6(7/2) bands have different temperature dependencies. The emission intensity ratios (R) for these bands vary reproducibly with temperature, allowing the use of these materials as thermographic phosphors.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 2
DOI: 10.1021/ACS.CHEMMATER.8B02029
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“Microscopic investigation of as built and hot isostatic pressed Hastelloy X processed by Selective Laser Melting”. Pourbabak S, Montero-Sistiaga ML, Schryvers D, Van Humbeeck J, Vanmeensel K, Materials characterization 153, 366 (2019). http://doi.org/10.1016/j.matchar.2019.05.024
Abstract: Microstructural characteristics of Hastelloy X produced by Selective Laser Melting have been investigated by various microscopic techniques in the as built (AB) condition and after hot isostatic pressing (HIP). At sub-grain level the AB material consists of columnar high density dislocation cells while the HIP sample consists of columnar sub-grains with lower dislocation density that originate from the original dislocation cells, contradicting existing models. The sub-grains contain nanoscale precipitates enriched in Al, Ti, Cr and O, located at sub-grain boundaries in the AB condition and within the grains after HIP. At some grain boundaries, micrometer sized chromium carbides are detected after HIP. Micro hardness within the grains was found to decrease after HIP, which was attributed to the decrease in dislocation density due to recovery annealing.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 2.714
Times cited: 2
DOI: 10.1016/j.matchar.2019.05.024
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“Introducton to the special issue on electron crystallography”. Hadermann J, Palatinus L, And Materials 75, 462 (2019). http://doi.org/10.1107/S2052520619010783
Keywords: Editorial; Electron microscopy for materials research (EMAT)
Times cited: 2
DOI: 10.1107/S2052520619010783
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“Structure solution and refinement of metal-ion battery cathode materials using electron diffraction tomography”. Hadermann J, Abakumov AM, And Materials 75, 485 (2019). http://doi.org/10.1107/S2052520619008291
Abstract: The applicability of electron diffraction tomography to the structure solution and refinement of charged, discharged or cycled metal-ion battery positive electrode (cathode) materials is discussed in detail. As these materials are often only available in very small amounts as powders, the possibility of obtaining single-crystal data using electron diffraction tomography (EDT) provides unique access to crucial information complementary to X-ray diffraction, neutron diffraction and high-resolution transmission electron microscopy techniques. Using several examples, the ability of EDT to be used to detect lithium and refine its atomic position and occupancy, to solve the structure of materials ex situ at different states of charge and to obtain in situ data on structural changes occurring upon electrochemical cycling in liquid electrolyte is discussed.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 2
DOI: 10.1107/S2052520619008291
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“Mesoporous TiO2 from poly(N,N-dimethylacrylamide)-b-polystyrene block copolymers for long-term acetaldehyde photodegradation”. Billet J, Vandewalle S, Meire M, Blommaerts N, Lommens P, Verbruggen SW, De Buysser K, Du Prez F, Van Driesche I, Journal of materials science 55, 1933 (2019). http://doi.org/10.1007/S10853-019-04024-3
Abstract: Although already some mesoporous (2–50 nm) sol–gel TiO2 synthesis strategies exist, no pore size control beyond the 12 nm range is possible without using specialized organic structure-directing agents synthetized via controlled anionic/radical polymerizations. Here, we present the use of reversible addition–fragmentation chain transfer (RAFT) polymerization as a straightforward and industrial applicable alternative to the existing controlled polymerization methods for structure-directing agent synthesis. Poly(N,N-dimethylacrylamide)-block-polystyrene (PDMA-b-PS) block copolymer, synthesized via RAFT, was chosen as structure-directing agent for the formation of the mesoporous TiO2. Crack-free thin layers TiO2 with tunable pores from 8 to 45 nm could be acquired. For the first time, in a detailed and systematic approach, the influence of the block size and dispersity of the block copolymer is experimentally screened for their influence on the final meso-TiO2 layers. As expected, the mesoporous TiO2 pore sizes showed a clear correlation to the polystyrene block size and the dispersity of the PDMA-b-PS block copolymer. Surprisingly, the dispersity of the polymer was shown not to be affecting the standard deviation of the pores. As a consequence, RAFT could be seen as a viable alternative to the aforementioned controlled polymerization reactions for the synthesis of structure-directing agents enabling the formation of mesoporous pore size-controlled TiO2. To examine the photocatalytic activity of the mesoporous TiO2 thin layers, the degradation of acetaldehyde, a known indoor pollutant, was studied. Even after 3 years of aging, the TiO2 thin layer retained most of its activity.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 2.599
Times cited: 2
DOI: 10.1007/S10853-019-04024-3
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“Heterogeneity in the solar-powered consumer electronics market : a discrete choice experiments study”. Lizin S, Van Passel S, Vranken L, Solar Energy Materials And Solar Cells 156, 140 (2016). http://doi.org/10.1016/J.SOLMAT.2016.04.060
Abstract: Solar-powered consumer electronics are a likely starting point for organic photovoltaic (OPV) market development. Therefore, a generic discrete choice experiments study can determine how Flemish consumers value solar-cell characteristics for solar-poweied consumer electronics. Such characteristics include efficiency, lifetime, aesthetics, integratability, and price. We contribute to the literature by investigating preference heterogeneity in a solar-power niche market with an experimental design with a fixed reference alternative. The error components random parameter logit (ECRPL) with interactions provides a better fit than the latent class (LC) model for our choice data. The main effects had the expected signs. Consequently, aesthetics and integratability are OPV's assets. Nevertheless, heterogeneity puts the results that are valid for the average consumer into perspective. Based on our findings, OPV commercialization efforts should target the experienced, impatient user who highly values design and functionality. (C) 2016 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Engineering Management (ENM)
Impact Factor: 4.784
Times cited: 2
DOI: 10.1016/J.SOLMAT.2016.04.060
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“Boosting biomolecular interactions through DNA origami nano-tailored biosensing interfaces”. Rutten I, Daems D, Lammertyn J, Journal Of Materials Chemistry B 8, 3606 (2020). http://doi.org/10.1039/C9TB02439E
Abstract: The interaction between a bioreceptor and its target is key in developing sensitive, specific and robust diagnostic devices. Suboptimal interbioreceptor distances and bioreceptor orientation on the sensor surface, resulting from uncontrolled deposition, impede biomolecular interactions and lead to a decreased biosensor performance. In this work, we studied and implemented a 3D DNA origami design, for the first time comprised of assay specifically tailored anchoring points for the nanostructuring of the bioreceptor layer on the surface of disc-shaped microparticles in the continuous microfluidic environment of the innovative EvalutionTM platform. This bioreceptor immobilization strategy resulted in the formation of a less densely packed surface with reduced steric hindrance and favoured upward orientation. This increased bioreceptor accessibility led to a 4-fold enhanced binding kinetics and a 6-fold increase in binding efficiency compared to a directly immobilized non-DNA origami reference system. Moreover, the DNA origami nanotailored biosensing concept outperformed traditional aptamer coupling with respect to limit of detection (11 × improved) and signal-to-noise ratio (2.5 × improved) in an aptamer-based sandwich bioassay. In conclusion, our results highlight the potential of these DNA origami nanotailored surfaces to improve biomolecular interactions at the sensing surface, thereby increasing the overall performance of biosensing devices. The combination of the intrinsic advantages of DNA origami together with a smart design enables bottom-up nanoscale engineering of the sensor surface, leading towards the next generation of improved diagnostic sensing devices.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 7
Times cited: 2
DOI: 10.1039/C9TB02439E
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“Origin of the extra capacity in nitrogen-doped porous carbon nanofibers for high-performance potassium ion batteries”. Liu F, Meng J, Xia F, Liu Z, Peng H, Sun C, Xu L, Van Tendeloo G, Mai L, Wu J, Journal Of Materials Chemistry A 8, 18079 (2020). http://doi.org/10.1039/D0TA05626J
Abstract: While graphite has limited capacity as an anode material for potassium-ion batteries, nitrogen-doped carbon materials are more promising as extra capacity can usually be produced. However, the mechanism behind the origin of the extra capacity remains largely unclear. Here, the potassium storage mechanisms have been systematically studied in freestanding and porous N-doped carbon nanofibers with an additional similar to 100 mA h g(-1)discharge capacity at 0.1 A g(-1). The extra capacity is generated in the whole voltage window range from 0.01 to 2 V, which corresponds to both surface/interface K-ion absorptions due to the pyridinic N and pyrrolic N induced atomic vacancies and layer-by-layer intercalation due to the effects of graphitic N. As revealed by transmission electron microscopy, the N-doped samples have a clear and enhanced K-intercalation reaction. Theoretical calculations confirmed that the micropores with pyridinic N and pyrrolic N provide extra sites to form bonds with K, resulting in the extra capacity at high voltage. The chemical absorption of K-ions occurring inside the defective graphitic layer will prompt fast diffusion of K-ions and full realization of the intercalation capacity at low voltage. The approach of preparing N-doped carbon-based materials and the mechanism revealed by this work provide directions for the development of advanced materials for efficient energy storage.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 11.9
Times cited: 2
DOI: 10.1039/D0TA05626J
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“Reversible and concerted atom diffusion on supported gold nanoparticles”. Liu P, Madsen J, Schiotz J, Wagner JB, Hansen TW, Journal Of Physics-materials 3, 024009 (2020). http://doi.org/10.1088/2515-7639/AB82B4
Abstract: Traditionally, direct imaging of atom diffusion is only available by scanning tunneling microscopy and field ion microscopy on geometry-constrained samples: flat surfaces for STM and needle tips for FIM. Here we show time-resolved atomic-scale HRTEM investigations of CeO2-supported Au nanoparticle surfaces to characterize the surface dynamics of atom columns on gold nanoparticles. The observed surface dynamics have been categorized into four types: layer jumping, layer gliding, re-orientation and surface reconstruction. We successfully captured atoms moving in a concerted manner with a time resolution of 0.1 s. A quantitative approach for measuring the dynamics in various gaseous surroundings at elevated temperatures is presented. An approach for measuring quantitative electron beam effects on the surface dynamics is presented by counting atom column occupation as a function of time under a range of dose rates in high vacuum.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 2
DOI: 10.1088/2515-7639/AB82B4
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“Ion exchange in atomically thin clays and micas”. Zou Y-C, Mogg L, Clark N, Bacaksiz C, Milanovic S, Sreepal V, Hao G-P, Wang Y-C, Hopkinson DG, Gorbachev R, Shaw S, Novoselov KS, Raveendran-Nair R, Peeters FM, Lozada-Hidalgo M, Haigh SJ, Nature Materials 20, 1677 (2021). http://doi.org/10.1038/S41563-021-01134-9
Abstract: The physical properties of clays and micas can be controlled by exchanging ions in the crystal lattice. Atomically thin materials can have superior properties in a range of membrane applications, yet the ion-exchange process itself remains largely unexplored in few-layer crystals. Here we use atomic-resolution scanning transmission electron microscopy to study the dynamics of ion exchange and reveal individual ion binding sites in atomically thin and artificially restacked clays and micas. We find that the ion diffusion coefficient for the interlayer space of atomically thin samples is up to 10(4) times larger than in bulk crystals and approaches its value in free water. Samples where no bulk exchange is expected display fast exchange at restacked interfaces, where the exchanged ions arrange in islands with dimensions controlled by the moire superlattice dimensions. We attribute the fast ion diffusion to enhanced interlayer expandability resulting from weaker interlayer binding forces in both atomically thin and restacked materials. This work provides atomic scale insights into ion diffusion in highly confined spaces and suggests strategies to design exfoliated clay membranes with enhanced performance. Layered clays are of interest for membranes and many other applications but their ion-exchange dynamics remain unexplored in atomically thin materials. Here, using electron microscopy, it is found that the ion diffusion for few-layer two-dimensional clays approaches that of free water and that superlattice cation islands can form in twisted and restacked materials.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 39.737
Times cited: 2
DOI: 10.1038/S41563-021-01134-9
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“Pivotal role of magnetic ordering and strain in lattice thermal conductivity of chromium-trihalide monolayers”. Pandey T, Peeters FM, Milošević, MV, 2D materials 9, 015034 (2022). http://doi.org/10.1088/2053-1583/AC427E
Abstract: Understanding the coupling between spin and phonons is critical for controlling the lattice thermal conductivity (kappa ( l )) in magnetic materials, as we demonstrate here for CrX3 (X = Br and I) monolayers. We show that these compounds exhibit large spin-phonon coupling (SPC), dominated by out-of-plane vibrations of Cr atoms, resulting in significantly different phonon dispersions in ferromagnetic (FM) and paramagnetic (PM) phases. Lattice thermal conductivity calculations provide additional evidence for strong SPC, where particularly large kappa ( l ) is found for the FM phase. Most strikingly, PM and FM phases exhibit radically different behavior with tensile strain, where kappa ( l ) increases with strain for the PM phase, and strongly decreases for the FM phase-as we explain through analysis of phonon lifetimes and scattering rates. Taken all together, we uncover the high significance of SPC on the phonon transport in CrX3 monolayers, a result extendable to other 2D magnetic materials, that will be useful in further design of thermal spin devices.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 5.5
Times cited: 2
DOI: 10.1088/2053-1583/AC427E
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