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“Chiral properties of topological-state loops”. Grujić, MM, Tadic MZ, Peeters FM, Physical review : B : condensed matter and materials physics 91, 245432 (2015). http://doi.org/10.1103/PhysRevB.91.245432
Abstract: The angular momentum quantization of chiral gapless modes confined to a circularly shaped interface between two different topological phases is investigated. By examining several different setups, we show analytically that the angular momentum of the topological modes exhibits a highly chiral behavior, and can be coupled to spin and/or valley degrees of freedom, reflecting the nature of the interface states. A simple general one-dimensional model, valid for arbitrarily shaped loops, is shown to predict the corresponding energies and the magnetic moments. These loops can be viewed as building blocks for artificial magnets with tunable and highly diverse properties.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 6
DOI: 10.1103/PhysRevB.91.245432
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“Coherent level mixing in dot energy spectra measured by magnetoresonant tunneling spectroscopy of vertical quantum dot molecules”. Payette C, Amaha S, Yu G, Gupta JA, Austing DG, Nair SV, Partoens B, Tarucha S, Physical review : B : condensed matter and materials physics 81, 245310 (2010). http://doi.org/10.1103/PhysRevB.81.245310
Abstract: We study by magnetoresonant tunneling spectroscopy single-particle energy spectra of the constituent weakly coupled dots in vertical quantum dot molecules over a wide energy window. The measured energy spectra are well modeled by calculated spectra for dots with in-plane confinement potentials that are elliptical and parabolic in form. However, in the regions where two, three, or four single-particle energy levels are naively expected to cross, we observe pronounced level anticrossing behavior and strong variations in the resonant currents as a consequence of coherent mixing induced by small deviations in the nearly ideal dot confinement potentials. We present detailed analysis of the energy spectra, and focus on two examples of three-level crossings whereby the coherent mixing leads to concurrent suppression and enhancement of the resonant currents when the anticrossing levels are minimally separated. The suppression of resonant current is of particular interest since it is a signature of dark state formation due to destructive interference. We also describe in detail and compare two measurement strategies to reliably extract the resonant currents required to characterize the level mixing.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 6
DOI: 10.1103/PhysRevB.81.245310
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“Confinement effects on electron and phonon degrees of freedom in nanofilm superconductors : a Green function approach”. Saniz R, Partoens B, Peeters FM, Physical review : B : condensed matter and materials physics 87, 064510 (2013). http://doi.org/10.1103/PhysRevB.87.064510
Abstract: The Green function approach to the Bardeen-Cooper-Schrieffer theory of superconductivity is used to study nanofilms. We go beyond previous models and include effects of confinement on the strength of the electron-phonon coupling as well as on the electronic spectrum and on the phonon modes. Within our approach, we find that in ultrathin films, confinement effects on the electronic screening become very important. Indeed, contrary to what has been advanced in recent years, the sudden increases of the density of states when new bands start to be occupied as the film thickness increases, tend to suppress the critical temperature rather than to enhance it. On the other hand, the increase of the number of phonon modes with increasing number of monolayers in the film leads to an increase in the critical temperature. As a consequence, the superconducting critical parameters in such nanofilms are determined by these two competing effects. Furthermore, in sufficiently thin films, the condensate consists of well-defined subcondensates associated with the occupied bands, each with a distinct coherence length. The subcondensates can interfere constructively or destructively giving rise to an interference pattern in the Cooper pair probability density.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 6
DOI: 10.1103/PhysRevB.87.064510
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“Dyakonov-Perel spin relaxation in InSb/AlxIn1-xSb quantum wells”. Li J, Chang K, Peeters FM, Physical review : B : solid state 80, 153307 (2009). http://doi.org/10.1103/PhysRevB.80.153307
Abstract: We investigate theoretically the Dyakonov-Perel spin relaxation time by solving the eight-band Kane model and Poisson equation self-consistently. Our results show distinct behavior with the single-band model due to the anomalous spin-orbit interactions in narrow band-gap semiconductors, and agree well with the experiment values reported in recent experiment [K. L. Litvinenko et al., New J. Phys. 8, 49 (2006)]. We find a strong resonant enhancement of the spin relaxation time appears for spin align along [11̅ 0] at a certain electron density at 4 K. This resonant peak is smeared out with increasing the temperature.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 6
DOI: 10.1103/PhysRevB.80.153307
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“Elastic modes of vortex configurations in thin disks”. Cabral LRE, Peeters FM, Physical review : B : condensed matter and materials physics 70, 214522 (2004). http://doi.org/10.1103/PhysRevB.70.214522
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 6
DOI: 10.1103/PhysRevB.70.214522
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“Low-strain Si/O superlattices with tunable electronic properties : ab initio calculations”. Nishio K, Lu AKA, Pourtois G, Physical review : B : condensed matter and materials physics 91, 165303 (2015). http://doi.org/10.1103/PhysRevB.91.165303
Abstract: We propose that low-strain Si/O superlattices can be constructed by connecting reconstructed Si{001} surfaces by Si-O-Si bridges. Ab initio calculations show that our models are energetically more favorable than all the models proposed so far. The part of our Si/O superlattice model is experimentally accessible just by oxidizing a Si( 001) substrate. To complete our Si/O superlattice model, we propose a three-step method. We also explore the potential of our Si/O superlattice models for new materials used in future Si electronics. We find that the location of the channel where the carriers travel can be controlled between the interfaces and the Si layers by the insertion of O atoms into the Si-Si dimers. By revealing the origins of the interface electron and hole states, we find that similar interface states should be easily achieved for Si slabs and Si substrates. Interestingly, the interface electrons and holes have small effective masses in the direction parallel to the channel and large effective masses in the direction normal to the channel, which makes the Si/O superlattices attractive to be used for channel materials. We also find that the valley splitting of Si is enhanced by the formation of the Si/O/Si interfaces, which is ideal for developing Si-based qubits. Our findings open new perspectives to design and control the electronic properties of Si.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.836
Times cited: 6
DOI: 10.1103/PhysRevB.91.165303
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“Many-body effects in the cyclotron resonance of a magnetic dot”. Nguten NTT, Peeters FM, Physical review : B : solid state 80, 115335 (2009). http://doi.org/10.1103/PhysRevB.80.115335
Abstract: Intraband cyclotron resonance (CR) transitions of a two-electron quantum dot containing a single magnetic ion is investigated for different Coulomb interaction strengths and different positions of the magnetic ion. In contrast to the usual parabolic quantum dots where CR is independent of the number of electrons, we found here that due to the presence of the magnetic ion Kohn's theorem no longer holds and CR is different for systems with different number of electrons and different effective electron-electron Coulomb interaction strength. Many-body effects result in shifts in the transition energies and change the number of CR lines. The position of the magnetic ion inside the quantum dot affects the structure of the CR spectrum by changing the position and the number of crossings and anticrossings in the transition energies and oscillator strengths.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 6
DOI: 10.1103/PhysRevB.80.115335
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“Orientational properties of C70 and C80 fullerenes in carbon nanotubes”. Verberck B, Physical review : B : condensed matter and materials physics 83, 045405 (2011). http://doi.org/10.1103/PhysRevB.83.045405
Abstract: We present energy calculations of a C80 molecule with D5d symmetry encapsulated in a carbon nanotube. The approximation of a continuous tube rather than a rolled-up graphene sheet, justified by comparison with atomistic calculations, allows an expansion of the energy field into symmetry-adapted rotator functions. For a given tube radius R, we observe a strong dependence of the interaction energy on the molecular tilt angle and on the molecules lateral position in the tube. We observe a transition from on-axis lying orientations to tilted orientations at R1≈6.95 Å and a subsequent transition to standing orientations at R2≈7.6 Å. For tube radii larger than R3≈8.0 Å, the molecule starts to occupy off-axis positions and assumes a lying orientation. Results are compared to the case of C70 molecules, with D5h symmetry. Our findings are consistent with recent high-resolution transmission electron microscopy measurements and are relevant for the design of new materials with tunable electronic properties.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 6
DOI: 10.1103/PhysRevB.83.045405
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“Spin-orbit interaction controlled properties of two-dimensional superlattices”. Földi P, Szaszkó-Bogár V, Peeters FM, Physical review : B : condensed matter and materials physics 82, 115302 (2010). http://doi.org/10.1103/PhysRevB.82.115302
Abstract: The band structure of two-dimensional artificial superlattices in the presence of (Rashba-type) spin-orbit interaction (SOI) is presented. The position and shape of the energy bands in these spintronic crystals depend on the geometry as well as the strength of the SOI, which can be tuned by external gate voltages. For finite mesoscopic arrays, we show that their conductance properties and possible applications can be understood from these spin-dependent band diagrams.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 6
DOI: 10.1103/PhysRevB.82.115302
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“Structural transitions in vertically and horizontally coupled parabolic channels of Wigner crystals”. Galván Moya JE, Nelissen K, Peeters FM, Physical review : B : condensed matter and materials physics 86, 184102 (2012). http://doi.org/10.1103/PhysRevB.86.184102
Abstract: Structural phase transitions in two vertically or horizontally coupled channels of strongly interacting particles are investigated. The particles are free to move in the x direction but are confined by a parabolic potential in the y direction. They interact with each other through a screened power-law potential (r(-n)e(-r/lambda)). In vertically coupled systems, the channels are stacked above each other in the direction perpendicular to the (x, y) plane, while in horizontally coupled systems both channels are aligned in the confinement direction. Using Monte Carlo (MC) simulations we obtain the ground-state configurations and the structural transitions as a function of the linear particle density and the separation between the channels. At zero temperature, the vertically coupled system exhibits a rich phase diagram with continuous and discontinuous transitions. On the other hand, the horizontally coupled system exhibits only a very limited number of phase transitions due to its symmetry. Further, we calculated the normal modes for the Wigner crystals in both cases. From MC simulations, we found that in the case of vertically coupled systems, the zigzag transition is only possible for low densities. A Ginzburg-Landau theory for the zigzag transition is presented, which predicts correctly the behavior of this transition from which we interpret the structural phase transition of the Wigner crystal through the reduction of the Brillouin zone.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 6
DOI: 10.1103/PhysRevB.86.184102
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“Symmetric and asymmetric states in a mesoscopic superconducting wire in the voltage-driven regime”. Vodolazov DY, Peeters FM, Physical review : B : condensed matter and materials physics 75, 104515 (2007). http://doi.org/10.1103/PhysRevB.75.104515
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 6
DOI: 10.1103/PhysRevB.75.104515
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“(CuCl)LaTa2O\text{7} and quantum phase transition in the (CuX)LaM2O7 family (X=Cl, Br, M=Nb, Ta)”. Tsirlin AA, Abakumov AM, Ritter C, Rosner H, Physical review : B : condensed matter and materials physics 86, 064440 (2012). http://doi.org/10.1103/PhysRevB.86.064440
Abstract: We apply neutron diffraction, high-resolution synchrotron x-ray diffraction, magnetization measurements, electronic structure calculations, and quantum Monte-Carlo simulations to unravel the structure and magnetism of (CuCl)LaTa2O7. Despite the pseudo-tetragonal crystallographic unit cell, this compound features an orthorhombic superstructure, similar to the Nb-containing (CuX)LaNb2O7 with X = Cl and Br. The spin lattice entails dimers formed by the antiferromagnetic fourth-neighbor coupling J(4), as well as a large number of nonequivalent interdimer couplings quantified by an effective exchange parameter J(eff). In (CuCl)LaTa2O7, the interdimer couplings are sufficiently strong to induce the long-range magnetic order with the Neel temperature T-N similar or equal to 7 K and the ordered magnetic moment of 0.53 mu(B), as measured with neutron diffraction. This magnetic behavior can be accounted for by J(eff)/J(4) similar or equal to 1.6 and J(4) similar or equal to 16 K. We further propose a general magnetic phase diagram for the (CuCl)LaNb2O7-type compounds, and explain the transition from the gapped spin-singlet (dimer) ground state in (CuCl)LaNb2O7 to the long-range antiferromagnetic order in (CuCl)LaTa2O7 and (CuBr)LaNb2O7 by an increase in the magnitude of the interdimer couplings J(eff)/J(4), with the (CuCl)LaM2O7 (M = Nb, Ta) compounds lying on different sides of the quantum critical point that separates the singlet and long-range-ordered magnetic ground states.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 6
DOI: 10.1103/PhysRevB.86.064440
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“Tomasch effect in nanoscale superconductors”. Zhang L-F, Covaci L, Peeters FM, Physical review : B : condensed matter and materials physics 91, 024508 (2015). http://doi.org/10.1103/PhysRevB.91.024508
Abstract: The Tomasch effect (TE) is due to quasiparticle interference (QPI) as induced by a nonuniform superconducting order parameter, which results in oscillations in the density of states (DOS) at energies above the superconducting gap. Quantum confinement in nanoscale superconductors leads to an inhomogenerous distribution of the Cooperpair condensate, which, as we found, triggers the manifestation of a new TE. We investigate the electronic structure of nanoscale superconductors by solving the Bogoliubov-de Gennes (BdG) equations self-consistently and describe the TE determined by two types of processes, involving two-or three-subband QPIs. Both types of QPIs result in additional BCS-like Bogoliubov-quasiparticles and BCS-like energy gaps leading to oscillations in the DOS and modulated wave patterns in the local density of states. These effects are strongly related to the symmetries of the system. A reduced 4 x 4 inter-subband BdG Hamiltonian is established in order to describe analytically the TE of two-subband QPIs. Our study is relevant to nanoscale superconductors, either nanowires or thin films, Bose-Einsten condensates, and confined systems such as two-dimensional electron gas interface superconductivity.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 6
DOI: 10.1103/PhysRevB.91.024508
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“Laser microprobe mass spectrometry: principle and applications in biology and medicine”. van Vaeck L, Poels K, de Nollin S, Hachimi A, Gijbels R, Cell biology international 21, 635 (1997). http://doi.org/10.1006/cbir.1997.0198
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.831
Times cited: 6
DOI: 10.1006/cbir.1997.0198
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“Fitting the momentum dependent loss function in EELS”. Bertoni G, Verbeeck J, Brosens F, Microscopy research and technique 74, 212 (2011). http://doi.org/10.1002/jemt.20894
Abstract: Momentum dependent inelastic plasmon scattering can be measured by electron energy loss in a transmission electron microscope. From energy filtered diffraction, the characteristic angle of scattering and the cutoff angle are measured, using a thin film of aluminum as a model test. Rather than deconvolving the data (as done in previous works), a fitting technique is used to extract the loss function from angular resolved spectra, starting from a simple model simulation.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Theory of quantum systems and complex systems
Impact Factor: 1.147
Times cited: 6
DOI: 10.1002/jemt.20894
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“Ba2Y(Nb/Ta)O6–Doped YBCO Films on Biaxially Textured Ni–5at.% W Substrates”. Sieger M, Pahlke P, Hanisch J, Sparing M, Bianchetti M, MacManus-Driscoll J, Lao M, Eisterer M, Meledin A, Van Tendeloo G, Nast R, Schultz L, Holzapfel B, Huhne R, IEEE transactions on applied superconductivity 26, 1 (2016). http://doi.org/10.1109/TASC.2016.2539254
Abstract: The incorporation of nanoscaled pinning centers in superconducting YBa2Cu3O7-d (YBCO) films is one of the core topics to enhance the critical current density Jc(B, Q) of coated conductors. The mixed double-perovskite Ba2Y(Nb/Ta)O6 (BYNTO) can be grown in nanosized columns parallel the YBCO c-axis and in step-like patterns, making it customizable to meet specific working conditions (T, B, Q). We compare a 1.6 μm thick film of pure YBCO and a similar film with additional 5 mol% of BYNTO, grown by pulsed laser deposition with a growth rate of 1.6 nm/s on buffered biaxially textured Ni-5at.% W tape. Our doped sample shows nanosized BYNTO columns parallel cYBCO and plates in the ab-plane containing Y, Nb and Ta. An improved homogeneity of the critical current density Jc over the sample was evaluated from trapped field profiles measured with a scanning Hall probe microscope. The mean Jc in rolling direction of the tape is 1.8 MA/cm² (77 K, self-field) and doubles the value of the undoped sample. Angular dependent measurements of the critical current density, Jc(Q), show a decreased anisotropy of the doped film for various magnetic fields at 77 K as well as 64 K.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 6
DOI: 10.1109/TASC.2016.2539254
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“The determination of the interface structure between ionocovalent compounds: the general case study of the Al2O3/ZrO2 large mis-fit system”. Trolliard G, Benmechta R, Mercurio D, Lebedev OI, Journal of materials chemistry 16, 3640 (2006). http://doi.org/10.1039/b604232e
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 6
DOI: 10.1039/b604232e
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“Quantum cascades in nano-engineered superconductors : geometrical, thermal and paramagnetic effects”. Chen Y, Shanenko AA, Croitoru MD, Peeters FM, Journal of physics : condensed matter 24, 265702 (2012). http://doi.org/10.1088/0953-8984/24/26/265702
Abstract: The effect of a parallel magnetic field on the orbital motion of electrons in high-quality superconducting nanowires resulting in a superconductor-to-normal transition which occurs through a cascade of jumps in the order parameter as a function of the magnetic field. Such cascades originate from the transverse size quantization that splits the conduction band into a series of subbands. Here, based on a numerical solution of the Bogoliubov-de Gennes equations for a hollow nanocylinder, we investigate how the quantum-size cascades depend on the confining geometry, i.e., by changing the cylinder radius R and its thickness d we cover the range from the nanowire-like to the nanofilm-like regime. The cascades are shown to become much less pronounced when increasing R/d, i.e., when the nanofilm-like regime is approached. When the temperature is non-zero they are thermally smoothed. This includes the spin-magnetic-field interaction which reduces the critical (depairing) parallel magnetic field H-c,H-parallel to but does not have any qualitative effect on the quantum cascades. From our calculations it is seen that the paramagnetic limiting field H-par significantly exceeds H-c,H-parallel to even in extremely narrow nanocylinders, i.e., when R, d are down to a few nanometers, and H-c,H-parallel to is only about 10% larger when switching-off the spin-magnetic-field interaction in this case. Both characteristic fields, H-c,H-parallel to and H-par, exhibit pronounced quantum-size oscillations. We demonstrate that the quantum cascades and the quantum-size oscillations survive in the presence of surface roughness.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.649
Times cited: 6
DOI: 10.1088/0953-8984/24/26/265702
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“Confined states in graphene quantum blisters”. Abdullah HM, Bahlouli H, Peeters FM, Van Duppen B, Journal of physics : condensed matter 30, 385301 (2018). http://doi.org/10.1088/1361-648X/AAD9C7
Abstract: Bilayer graphene samples may exhibit regions where the two layers are locally delaminated forming a so-called quanttun blister in the graphene sheet. Electron and hole states can be confined in this graphene quantum blisters (GQB) by applying a global electrostatic bias. We scrutinize the electronic properties of these confined states under the variation of interlayer bias, coupling, and blister's size. The spectra display strong anti-crossings due to the coupling of the confined states on upper and lower layers inside the blister. These spectra are layer localized where the respective confined states reside on either layer or equally distributed. For finite angular momentum, this layer localization can be at the edge of the blister and corresponds to degenerate modes of opposite momenta. Furthermore, the energy levels in GQB exhibit electron-hole symmetry that is sensitive to the electrostatic bias. Finally, we demonstrate that confinement in GQB persists even in the presence of a variation in the interlayer coupling.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.649
Times cited: 6
DOI: 10.1088/1361-648X/AAD9C7
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“Unique nanostructural features in Fe, Mn-doped YBCO thin films”. Meledin A, Turner S, Cayado P, Mundet B, Solano E, Ricart S, Ros J, Puig T, Obradors X, Van Tendeloo G, Superconductor science and technology 29, 125009 (2016). http://doi.org/10.1088/0953-2048/29/12/125009
Abstract: An attempt to grow a thin epitaxial composite film of YBa2Cu3O7−δ (YBCO) with spinel MnFe2O4 (MFO) nanoparticles on a LAO substrate using the CSD approach resulted in a decomposition of the spinel and various doping modes of YBCO with the Fe and Mn cations. These nanostructural effects lead to a lowering of T c and a slight J c increase in field. Using a combination of advanced transmission electron microscopy (TEM) techniques such as atomic resolution high-angle annular dark field scanning TEM, energy dispersive x-ray spectroscopy and electron energy-loss spectroscopy we have been able to decipher and characterize the effects of the Fe and Mn doping on the film architecture. The YBaCuFeO5 anion-deficient double perovskite phase was detected in the form of 3D inclusions as well as epitaxially grown lamellas within the YBCO matrix. These nano-inclusions play a positive role as pinning centers responsible for the J c/J sf (H) dependency smoothening at high magnetic fields in the YBCO-MFO films with respect to the pristine YBCO films.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.878
Times cited: 6
DOI: 10.1088/0953-2048/29/12/125009
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“Tilted BaHfO3 nanorod artificial pinning centres in REBCO films on inclined substrate deposited-MgO coated conductor templates”. Stafford BH, Sieger M, Ottolinger R, Meledin A, Strickland NM, Wimbush SC, Van Tendeloo G, Huehne R, Schultz L, Superconductor science and technology 30, 055002 (2017). http://doi.org/10.1088/1361-6668/AA621D
Abstract: We grow BaHfO3 (BHO) nanorods in REBa2Cu3O7-x (REBCO, RE: Gd or Y) thin films on metal tapes coated with the inclined substrate deposited (ISD)-MgO template by both electron beam physical vapour deposition and pulsed laser deposition. In both cases the nanorods are inclined by an angle of 21 degrees-29 degrees with respect to the sample surface normal as a consequence of the tilted growth of the REBCO film resulting from the ISD-MgO layer. We present angular critical current density (J(c)) anisotropy as well as field- and temperature-dependant J(c) data of the BHO nanorod-containing GdBCO films demonstrating an increase in J(c) over a wide range of temperatures between 30 and 77 K and magnetic fields up to 8 T. In addition, we show that the angle of the peak in the J(c) anisotropy curve resulting from the nanorods is dependent both on temperature and magnetic field. The largest J(c) enhancement from the addition of the nanorods was found to occur at 30 K, 3 T, resulting in a J(c) of 3.0 MA cm(-2).
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.878
Times cited: 6
DOI: 10.1088/1361-6668/AA621D
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“Hierarchically dual-mesoporous TiO2 microspheres for enhanced photocatalytic properties and lithium storage”. Xiao S, Lu Y, Xiao B-Y, Wu L, Song J-P, Xiao Y-X, Wu S-M, Hu J, Wang Y, Chang G-G, Tian G, Lenaerts S, Janiak C, Yang X-Y, Su B-L, Chemistry: a European journal 24, 13246 (2018). http://doi.org/10.1002/CHEM.201801933
Abstract: Hierarchically dual‐mesoporous TiO2 microspheres have been synthesized via a solvothermal process in the presence of 1‐butyl‐3‐methylmidazolium tetrafluoroborate ([BMIm][BF4]) and diethylenetriamine (DETA) as co‐templates. Secondary mesostructured defects in the hierarchical TiO2 microspheres produce the oxygen vacancies, which not only significantly enhance the photocatalytic activity on degrading methyl blue (over 1.7 times to P25) and acetone (over 2.9 times of P25), but which also are beneficial for lithium storage. Moreover, we propose a mechanism to obtain a better understanding of the role of dual mesoporosity of TiO2 microspheres for enhancing the molecular diffusion, ion transportation and electron transformation.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 5.317
Times cited: 6
DOI: 10.1002/CHEM.201801933
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“Effect of helium/argon gas ratio in a He-Ar-Cu+ IR hollow-cathode discharge laser : modeling study and comparison with experiments”. Bogaerts A, Grozeva M, Applied physics B : lasers and optics 76, 299 (2003). http://doi.org/10.1007/s00340-002-1093-3
Abstract: The He-Ar-Cu+ IR laser operates in a hollow-cathode discharge, typically in a mixture of helium with a few-% Ar. The population inversion of the Cu+ ion levels, responsible for laser action, is attributed to asymmetric charge transfer between He+ ions and sputtered Cu atoms. The Ar gas is added to promote sputtering of the Cu cathode. In this paper, a hybrid modeling network consisting of several different models for the various plasma species present in a He-Ar-Cu hollow-cathode discharge is applied to investigate the effect of Ar concentration in the gas mixture on the discharge behavior, and to find the optimum He/Ar gas ratio for laser operation. It is found that the densities of electrons, Ar+ ions, Ar-m* metastable atoms, sputtered Cu atoms and Cu+ ions increase upon the addition of more Ar gas, whereas the densities of He+ ions, He-2(+) ions and He-m* metastable atoms drop considerably. The product of the calculated Cu atom and He+ ion densities, which determines the production rate of the upper laser levels, and hence probably also the laser output power, is found to reach a maximum around 1-5% Ar addition. This calculation result is compared to experimental measurements, and reasonable agreement has been reached.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.696
Times cited: 6
DOI: 10.1007/s00340-002-1093-3
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“Biomonitoring of atmospheric particulate pollution via chemical composition and magnetic properties of roadside tree leaves”. Kardel F, Wuyts K, De Wael K, Samson R, Environmental Science and Pollution Research 25, 25994 (2018). http://doi.org/10.1007/S11356-018-2592-Z
Abstract: Particulate matter (PM) is a main atmospheric pollution which threats human health and well-being. In this research, we chemically and magnetically analysed roadside tree leaves, collected from three tree species in two main roads (from two different cities) and a reference area, for 28 elements and the saturation isothermal remanent magnetisation. Comparison of unwashed and washed leaves revealed that deposited particles on the leaf surface contain various elements including Al, Ca, Fe, Mg, Mn, Na, Si, Ti, Ba, Co, Cr, Cu, Ni, Rb, V, Zn and Zr. Moreover, there was no significant difference between washed/unwashed leaves in Cl, K, P, S, As, Cd, Cs, Pb, Sn and Sr concentrations, which indicates tree leaves may not be a suitable biomonitor for these elements. Our results showed that site and tree species are important factors which affect atmospheric elements deposition. Among the three considered tree species, Chamaecyparis lawsoniana showed the highest potential for atmospheric particle accumulation. The PCA results revealed that Al, Fe, Ti, Co, Cr, Cu, Ni, Rb, Si, V, Zn and Zr indicated emissions from road traffic activities and soil dust; Ca, Mg and Na from sea salts and Mn and Sb from industrial activity. The biplot results showed that the site effect was much stronger than the species effect for all elements and saturation isothermal remanent magnetisation (SIRM) values. Moreover, elements from traffic, industrial activity and soil dust are significantly correlated with leaf SIRM indicating that leaf SIRM can be a suitable bioindicator of exposure to traffic-derived particles and soil dust, and not from sea salts. It is concluded that chemical composition and SIRM of urban tree leaves can serve as a good indicator of atmospheric PM pollution in Iran and anywhere else where the studied trees grow.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 2.741
Times cited: 6
DOI: 10.1007/S11356-018-2592-Z
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“Understanding the Effect of Iodide Ions on the Morphology of Gold Nanorods”. Amini MN, Altantzis T, Lobato I, Grzelczak M, Sánchez-Iglesias A, Van Aert S, Liz-Marzán LM, Partoens B, Bals S, Neyts EC, Particle and particle systems characterization 35, 1800051 (2018). http://doi.org/10.1002/ppsc.201800051
Abstract: The presence of iodide ions during the growth of gold nanorods strongly affects the shape of the final products, which is proposed to be due to selective iodide adsorption on certain crystallographic facets. Therefore, a detailed structural and morphological characterization of the starting rods is crucial toward understanding this effect. Electron tomography is used to determine the crystallographic indices of the lateral facets of gold nanorods, as well as those present at the tips. Based on this information, density functional theory calculations are used to determine the surface and interface energies of the observed facets and provide insight into the relationship between the amount of iodide ions in the growth solution and the final morphology of anisotropic gold nanoparticles.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.474
Times cited: 6
DOI: 10.1002/ppsc.201800051
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“Synthesis of monodispersed CoMoO4 nanoclusters on the ordered mesoporous carbons for environment-friendly supercapacitors”. Li J, Zhao C, Yang Y, Li C, Hollenkamp T, Burke N, Hu Z-Y, Van Tendeloo G, Chen W, Journal of alloys and compounds 810, 151841 (2019). http://doi.org/10.1016/J.JALLCOM.2019.151841
Abstract: Binary metal oxides with superior charge capacity and electrochemical activity have gained great interests. In this work, monodispersed CoMoO4 nanoclusters on the ordered mesoporous carbons were fabricated by a facile self-developed impregnation method. The synthesized hybrids possess improved wettability, high specific surface area (> 700m(2)/g) and regular mesoporous channels (similar to 4 nm), resulting in improved electrochemical performance for supercapacitors. These well-dispersed CoMoO4 nanoclusters exhibit a significant specific capacitance up to 367 F/g in the aqueous KNO3 electrolyte and good reversibility with a cycling efficiency of 99.8%. It is proposed that the mesoporous structure can facilitate the diffusion of electrolyte ions and then accelerate the electrochemical utilization of CoMoO4 nanoclusters. The results demonstrate that the produced binary metal oxide nanoclusters with excellent capacitance and good retention can be used as promising electrodes for the environment-friendly supercapacitors. (C) 2019 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: 6
DOI: 10.1016/J.JALLCOM.2019.151841
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“Computed electronic and optical properties of SnO2 under compressive stress”. Miglio A, Saniz R, Waroquiers D, Stankovski M, Giantomassi M, Hautier G, Rignanese G-M, Gonze X, Optical materials 38, 161 (2014). http://doi.org/10.1016/j.optmat.2014.10.017
Abstract: We consider the effects of three different types of applied compressive stress on the structural, electronic and optical properties of rutile SnO2. We use standard density functional theory (OFT) to determine the structural parameters. The effective masses and the electronic band gap, as well as their stress derivatives, are computed within both DFT and many-body perturbation theory (MBPT). The stress derivatives for the SnO2 direct band gap are determined to be 62, 38 and 25 meV/GPa within MBPT for applied hydrostatic, biaxial and uniaxial stress, respectively. Compared to DFT, this is a clear improvement with respect to available experimental data. We also estimate the exciton binding energies and their stress coefficients and compute the absorption spectrum by solving the Bethe-Salpeter equation. (C) 2014 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.238
Times cited: 6
DOI: 10.1016/j.optmat.2014.10.017
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“Applications of advanced transmission electron microscopic techniques to Ni-Ti based shape memory materials”. Schryvers D, Potapov P, Santamarta R, Tirry W, Materials science and engineering: part A: structural materials: properties, microstructure and processing 378, 11 (2004). http://doi.org/10.1016/j.msea.2003.10.325
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.094
Times cited: 6
DOI: 10.1016/j.msea.2003.10.325
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“Martensitic transformations and microstructures in splat-cooled Ni-Al”. Schryvers D, Holland-Moritz D, Materials science and engineering: part A: structural materials: properties, microstructure and processing 273/275, 697 (1999). http://doi.org/10.1016/S0921-5093(99)00399-8
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.094
Times cited: 6
DOI: 10.1016/S0921-5093(99)00399-8
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“Commensurate vortex configurations in thin superconducting films nanostructured by square lattice of magnetic dots”. Milošević, MV, Peeters FM, Physica: C : superconductivity 404, 246 (2004). http://doi.org/10.1016/j.physc.2003.09.098
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.404
Times cited: 6
DOI: 10.1016/j.physc.2003.09.098
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