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“Influence of impurities and surface defects on the flux-induced current in mesoscopic d-wave superconducting loops”. Zha G-Q, Milošević, MV, Zhou S-P, Peeters FM, Physical review : B : condensed matter and materials physics 84, 132501 (2011). http://doi.org/10.1103/PhysRevB.84.132501
Abstract: We investigated the magnetic flux dependence of the supercurrent in mesoscopic d-wave superconducting loops, containing impurities and surface defects, by numerically solving the Bogoliubovde Gennes equations self-consistently. In the presence of impurities, bound states arise close to the Fermi energy. In the case of a single impurity, the flux-induced current is found to be suppressed. This can be different when more impurities are introduced in the sample due to the quantum interference effect, which depends sensitively on the relative position between the impurities. We further analyze the effect of small surface defects at the inner or outer edge of the loop, and show that indentation and bulge defects have pronounced and different effects on the supercurrent.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 13
DOI: 10.1103/PhysRevB.84.132501
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“Interplay between s-d exchange interaction and Rashba effect: spin-polarized transport”. Yang W, Chang K, Wu XG, Zheng HZ, Peeters FM;, Applied physics letters 89 (2006). http://doi.org/10.1063/1.2357888
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.411
Times cited: 10
DOI: 10.1063/1.2357888
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“Magnetically decorated multiwalled carbon nanotubes as dual MRI and SPECT contrast agents”. Wang JTW, Cabana L, Bourgognon M, Kafa H, Protti A, Venner K, Shah AM, Sosabowski JK, Mather SJ, Roig A, Ke X, Van Tendeloo G, de Rosales RTM, Tobias G, Al-Jamal KT, Advanced functional materials 24, 1880 (2014). http://doi.org/10.1002/adfm.201302892
Abstract: Carbon nanotubes (CNTs) are one of the most promising nanomaterials to be used in biomedicine for drug/gene delivery as well as biomedical imaging. This study develops radio-labeled, iron oxide-decorated multiwalled CNTs (MWNTs) as dual magnetic resonance (MR) and single photon emission computed tomography (SPECT) contrast agents. Hybrids containing different amounts of iron oxide are synthesized by in situ generation. Physicochemical characterisations reveal the presence of superparamagnetic iron oxide nanoparticles (SPION) granted the magnetic properties of the hybrids. Further comprehensive examinations including high resolution transmission electron microscopy (HRTEM), fast Fourier transform simulations, X-ray diffraction, and X-ray photoelectron spectroscopy assure the conformation of prepared SPION as γ-Fe2O3. High r2 relaxivities are obtained in both phantom and in vivo MRI compared to the clinically approved SPION Endorem. The hybrids are successfully radio labeled with technetium-99m through a functionalized bisphosphonate and enable SPECT/CT imaging and γ-scintigraphy to quantitatively analyze the biodistribution in mice. No abnormality is found by histological examination and the presence of SPION and MWNT are identified by Perls stain and Neutral Red stain, respectively. TEM images of liver and spleen tissues show the co-localization of SPION and MWNTs within the same intracellular vesicles, indicating the in vivo stability of the hybrids after intravenous injection. The results demonstrate the capability of the present SPIONMWNT hybrids as dual MRI and SPECT contrast agents for in vivo use.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 12.124
Times cited: 50
DOI: 10.1002/adfm.201302892
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“Magneto-optical imaging of flux penetration into arrays of Bi2Sr2CaCu2O8 microdisks”. Connolly MR, Milošević, MV, Bending SJ, Tamegai T, Physical review : B : solid state 78, 132501 (2008). http://doi.org/10.1103/PhysRevB.78.132501
Abstract: We have used differential magneto-optical (MO) imaging to investigate the mixed state of superconducting Bi2Sr2CaCu2O8+ (BSCCO) microdisks fabricated on a single-crystal sample. MO difference images of the stray field distribution over a range of out-of-plane fields allow us to distinguish between flux that is penetrating the disks and that entering the underlying BSCCO platelet. We find that flux preferentially flows along linear defects into the interstitial platelet regions up to a characteristic field Hp, above which flux enters the disks. We identify this as the field of first penetration of pancake vortices over the Bean-Livingston barrier around the disks, where Hp(T) at intermediate temperatures is well described by an exponentially decaying function with a characteristic temperature T0=19 K. At a given temperature, a minority of the disks exhibit a lower penetration field and we correlate the location of these disks with the linear defects in the BSCCO crystal.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 8
DOI: 10.1103/PhysRevB.78.132501
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“Mechanical resonance of the austenite/martensite interface and the pinning of the martensitic microstructures by dislocations in Cu74.08Al23.13Be2.79”. Salje EKH, Zhang H, Idrissi H, Schryvers D, Carpenter MA, Moya X, Planes A, Physical review: B: condensed matter and materials physics 80, 134114 (2009). http://doi.org/10.1103/PhysRevB.80.134114
Abstract: A single crystal of Cu74.08Al23.13Be2.79 undergoes a martensitic phase transition at 246 and 232 K under heating and cooling, respectively. The phase fronts between the austenite and martensite regions of the sample are weakly mobile with a power-law resonance under external stress fields. Surprisingly, the martensite phase is elastically much harder than the austenite phase showing that interfaces between various crystallographic variants are strongly pinned and cannot be moved by external stress while the phase boundary between the austenite and martensite regions in the sample remains mobile. This unusual behavior was studied by dynamical mechanical analysis (DMA) and resonant ultrasound spectroscopy. The remnant strain, storage modulus, and internal friction were recorded simultaneously for different applied forces in DMA. With increasing forces, the remnant strain increases monotonously while the internal friction peak height shows a minimum at 300 mN. Transmission electron microscopy shows that the pinning is generated by dislocations which are inherited from the austenite phase.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 38
DOI: 10.1103/PhysRevB.80.134114
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“Melting of graphene clusters”. Singh SK, Neek-Amal M, Peeters FM, Physical review : B : condensed matter and materials physics 87, 134103 (2013). http://doi.org/10.1103/PhysRevB.87.134103
Abstract: Density-functional tight-binding and classical molecular dynamics simulations are used to investigate the structural deformations and melting of planar carbon nanoclusters C-N with N = 2-55. The minimum-energy configurations for different clusters are used as starting configurations for the study of the temperature effects on the bond breaking and rotation in carbon lines (N < 6), carbon rings (5 < N < 19), and graphene nanoflakes. The larger the rings (graphene nanoflakes) the higher the transition temperature (melting point) with ring-to-line (perfect-to-defective) transition structures. The melting point was obtained by using the bond energy, the Lindemann criteria, and the specific heat. We found that hydrogen-passivated graphene nanoflakes (CNHM) have a larger melting temperature with a much smaller dependence on size. The edges in the graphene nanoflakes exhibit several different metastable configurations (isomers) during heating before melting occurs. DOI: 10.1103/PhysRevB.87.134103
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 28
DOI: 10.1103/PhysRevB.87.134103
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“Microstructural study of equiatomic PtTi martensite and the discovery of a new long-period structure”. Rotaru G-M, Tirry W, Sittner P, van Humbeeck J, Schryvers D, Acta materialia 55, 4447 (2007). http://doi.org/10.1016/j.actamat.2007.04.010
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 5.301
Times cited: 7
DOI: 10.1016/j.actamat.2007.04.010
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“Origin of magnetism and quasiparticles properties in Cr-doped TiO2”. da Pieve F, Di Matteo S, Rangel T, Giantomassi M, Lamoen D, Rignanese G-M, Gonze X, Physical review letters 110, 136402 (2013). http://doi.org/10.1103/PhysRevLett.110.136402
Abstract: Combining the local spin density approximation (LSDA)+U and an analysis of superexchange interactions beyond density functional theory, we describe the magnetic ground state of Cr-doped TiO2, an intensively studied and debated dilute magnetic oxide. In parallel, we correct our LSDA+U (+ superexchange) ground state through GW corrections (GW@LSDA+U) that reproduce the position of the impurity states and the band gaps in satisfying agreement with experiments. Because of the different topological coordinations of Cr-Cr bonds in the ground states of rutile and anatase, superexchange interactions induce either ferromagnetic or antiferromagnetic couplings of Cr ions. In Cr-doped anatase, this interaction leads to a new mechanism which stabilizes a (nonrobust) ferromagnetic ground state, in keeping with experimental evidence, without the need to invoke F-center exchange. The interplay between structural defects and vacancies in contributing to the superexchange is also unveiled.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 8.462
Times cited: 15
DOI: 10.1103/PhysRevLett.110.136402
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“Oscillating spin-orbit interaction as a source of spin-polarized wavepackets in two-terminal nanoscale devices”. Szaszko-Bogar V, Foeldi P, Peeters FM, Journal of physics : condensed matter 26, 135302 (2014). http://doi.org/10.1088/953-8984/26/13/135302
Abstract: Ballistic transport through nanoscale devices with time-dependent Rashba-type spin- orbit interaction (SOI) can lead to spin-polarized wavepackets that appear even for completely unpolarized input. The SOI that oscillates in a finite domain generates density and spin polarization fluctuations that leave the region as propagating waves. In particular, spin polarization has space and time dependence even in regions without SOI. Our results are based on an analytical solution of the time-dependent Schrodinger equation. The relevant Floquet quasi-energies that are obtained appear in the energy spectrum of both the transmitted and the reflected waves.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.649
DOI: 10.1088/953-8984/26/13/135302
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“Parametric amplification of vortex-antivortex pair generation in a Josephson junction”. Berdiyorov GR, Milošević, MV, Savel'ev S, Kusmartsev F, Peeters FM, Physical review : B : condensed matter and materials physics 90, 134505 (2014). http://doi.org/10.1103/PhysRevB.90.134505
Abstract: Using advanced three-dimensional simulations, we show that an Abrikosov vortex, trapped inside a cavity perpendicular to an artificial Josephson junction, can serve as a very efficient source for generation of Josephson vortex-antivortex pairs in the presence of the applied electric current. In such a case, the nucleation rate of the pairs can be tuned in a broad range by an out-of-plane ac magnetic field in a broad range of frequencies. This parametrically amplified vortex-antivortex nucleation can be considered as a macroscopic analog of the dynamic Casimir effect, where fluxon pairs mimic the photons and the ac magnetic field plays the role of the oscillating mirrors. The emerging vortex pairs in our system can be detected by the pronounced features in the measured voltage characteristics, or through the emitted electromagnetic radiation, and exhibit resonant dynamics with respect to the frequency of the applied magnetic field. Reported tunability of the Josephson oscillations can be useful for developing high-frequency emission devices.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 22
DOI: 10.1103/PhysRevB.90.134505
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“Resistive switching at manganite/manganite interfaces”. Kalkert C, Krisponeit J-O, Esseling M, Lebedev OI, Moshnyaga V, Damaschke B, Van Tendeloo G, Samwer K, Applied physics letters 99, 132512 (2011). http://doi.org/10.1063/1.3643425
Abstract: We report bipolar resistive switching between the interfaces of manganite nanocolumns. La0.7Sr0.3MnO3 films were prepared on Al2O3 substrates, where the films grow in nanocolumns from the substrate to the surface. Conductive atomic force microscopy directly detects that the resistive switching is located at the boundaries of the grains. Furthermore, mesoscopic transport measurements reveal a tunnel magnetoresistance. In combination with the resistive switching, this leads to a total of four different resistive states.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.411
Times cited: 10
DOI: 10.1063/1.3643425
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“Strain relaxation and oxygen superstructure modulation in epitaxial Sr4Fe6O13\pm\delta films”. Santiso J, Pardo JA, Solis C, Garcia G, Figueras A, Rossell MD, Van Tendeloo G, Applied physics letters 86, 132105 (2005). http://doi.org/10.1063/1.1886264
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.411
Times cited: 5
DOI: 10.1063/1.1886264
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“Structural and magnetic properties of the colossal magnetoresistance perovskite La0.85Ca0.15MnO3”. Lobanov MV, Balagurov AM, Pomjakushin VJ, Fischer P, Gutmann M, Abakumov AM, D'yachenko OG, Antipov EV, Lebedev OI, Van Tendeloo G, Physical review : B : condensed matter and materials physics 61, 8941 (2000). http://doi.org/10.1103/PhysRevB.61.8941
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 47
DOI: 10.1103/PhysRevB.61.8941
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“Superconducting films with weak pinning centers: incommenssurate vortex lattices”. Berdiyorov GR, Milošević, MV, Peeters FM, Physical review : B : condensed matter and materials physics 76, 134508 (2007). http://doi.org/10.1103/PhysRevB.76.134508
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 19
DOI: 10.1103/PhysRevB.76.134508
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“Superspace description, crystal structures, and electric conductiof the Ba4In6-xMgxO13-x/2 solid solutions”. Abakumov AM, Rossell MD, Gutnikova OY, Drozhzhin OA, Leonova LS, Dobrovolsky YA, Istomin SY, Van Tendeloo G, Antipov EV, Chemistry of materials 20, 4457 (2008). http://doi.org/10.1021/cm8004216
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 15
DOI: 10.1021/cm8004216
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“Symmetric and asymmetric vortex-antivortex molecules in a fourfold superconducting geometry”. Geurts R, Milošević, MV, Peeters FM, Physical review letters 97, 1 (2006). http://doi.org/10.1103/PhysRevLett.97.137002
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 8.462
Times cited: 54
DOI: 10.1103/PhysRevLett.97.137002
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“Tight-binding description of intrinsic superconducting correlations in multilayer graphene”. Muñoz WA, Covaci L, Peeters FM, Physical review : B : condensed matter and materials physics 87, 134509 (2013). http://doi.org/10.1103/PhysRevB.87.134509
Abstract: Using highly efficient GPU-based simulations of the tight-binding Bogoliubov-de Gennes equations we solve self-consistently for the pair correlation in rhombohedral (ABC) and Bernal (ABA) multilayer graphene by considering a finite intrinsic s-wave pairing potential. We find that the two different stacking configurations have opposite bulk/surface behavior for the order parameter. Surface superconductivity is robust for ABC stacked multilayer graphene even at very low pairing potentials for which the bulk order parameter vanishes, in agreement with a recent analytical approach. In contrast, for Bernal stacked multilayer graphene, we find that the order parameter is always suppressed at the surface and that there exists a critical value for the pairing potential below which no superconducting order is achieved. We considered different doping scenarios and find that homogeneous doping strongly suppresses surface superconductivity while nonhomogeneous field-induced doping has a much weaker effect on the superconducting order parameter. For multilayer structures with hybrid stacking (ABC and ABA) we find that when the thickness of each region is small (few layers), high-temperature surface superconductivity survives throughout the bulk due to the proximity effect between ABC/ABA interfaces where the order parameter is enhanced. DOI: 10.1103/PhysRevB.87.134509
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 37
DOI: 10.1103/PhysRevB.87.134509
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“Uniform-acceptance force-bias Monte Carlo method with time scale to study solid-state diffusion”. Mees MJ, Pourtois G, Neyts EC, Thijsse BJ, Stesmans A, Physical review : B : condensed matter and materials physics 85, 134301 (2012). http://doi.org/10.1103/PhysRevB.85.134301
Abstract: Monte Carlo (MC) methods have a long-standing history as partners of molecular dynamics (MD) to simulate the evolution of materials at the atomic scale. Among these techniques, the uniform-acceptance force-bias Monte Carlo (UFMC) method [ G. Dereli Mol. Simul. 8 351 (1992)] has recently attracted attention [ M. Timonova et al. Phys. Rev. B 81 144107 (2010)] thanks to its apparent capacity of being able to simulate physical processes in a reduced number of iterations compared to classical MD methods. The origin of this efficiency remains, however, unclear. In this work we derive a UFMC method starting from basic thermodynamic principles, which leads to an intuitive and unambiguous formalism. The approach includes a statistically relevant time step per Monte Carlo iteration, showing a significant speed-up compared to MD simulations. This time-stamped force-bias Monte Carlo (tfMC) formalism is tested on both simple one-dimensional and three-dimensional systems. Both test-cases give excellent results in agreement with analytical solutions and literature reports. The inclusion of a time scale, the simplicity of the method, and the enhancement of the time step compared to classical MD methods make this method very appealing for studying the dynamics of many-particle systems.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.836
Times cited: 31
DOI: 10.1103/PhysRevB.85.134301
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“Cold atmospheric plasma treatment of melanoma and glioblastoma cancer cells”. Vermeylen S, De Waele J, Vanuytsel S, De Backer J, Van der Paal J, Ramakers M, Leyssens K, Marcq E, Van Audenaerde J, L J Smits E, Dewilde S, Bogaerts A, Plasma processes and polymers 13, 1195 (2016). http://doi.org/10.1002/ppap.201600116
Abstract: In this paper, two types of melanoma and glioblastoma cancer cell lines are treated with cold atmospheric plasma to assess the effect of several parameters on the cell viability. The cell viability decreases with treatment duration and time until analysis in all cell lines with varying sensitivity. The majority of dead cells stains both AnnexinV (AnnV) and propidium iodide, indicating that the plasma-treated non-viable cells are mostly late apoptotic or necrotic. Genetic mutations might be involved in the response to plasma. Comparing the effects of two gas mixtures, as well as indirect plasma-activated medium versus direct treatment, gives different results per cell line. In conclusion, this study confirms the potential of plasma for cancer therapy and emphasizes the influence of experimental parameters on therapeutic outcome.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.846
Times cited: 26
DOI: 10.1002/ppap.201600116
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“Plasma processes and polymers third special issue on plasma and cancer”. Laroussi M, Bogaerts A, Barekzi N, Plasma processes and polymers 13, 1142 (2016). http://doi.org/10.1002/ppap.201600193
Keywords: Editorial; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.846
Times cited: 1
DOI: 10.1002/ppap.201600193
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“Ti surface doping of LiNi0.5Mn1.5O4−δpositive electrodes for lithium ion batteries”. Ulu Okudur F, D'Haen J, Vranken T, De Sloovere D, Verheijen M, Karakulina OM, Abakumov AM, Hadermann J, Van Bael MK, Hardy A, RSC advances 8, 7287 (2018). http://doi.org/10.1039/C7RA12932G
Abstract: The particle surface of LiNi0.5Mn1.5O4−δ (LNMO), a Li-ion battery cathode material, has been modified by Ti cation doping through a hydrolysis–condensation reaction followed by annealing in oxygen. The effect of different annealing temperatures (500–850 °C) on the Ti distribution and electrochemical performance of the surface modified LNMO was investigated. Ti cations diffuse from the preformed amorphous ‘TiOx’ layer into the LNMO surface during annealing at 500 °C. This results in a 2–4 nm thick Ti-rich spinel surface having lower Mn and Ni content compared to the core of the LNMO particles, which was observed with scanning transmission electron microscopy coupled with compositional EDX mapping. An increase in the annealing temperature promotes the formation of a Ti bulk doped LiNi(0.5−w)Mn(1.5+w)−tTitO4 phase and Ti-rich LiNi0.5Mn1.5−yTiyO4 segregates above 750 °C. Fourier-transform infrared spectrometry indicates increasing Ni–Mn ordering with annealing temperature, for both bare and surface modified LNMO. Ti surface modified LNMO annealed at 500 °C shows a superior cyclic stability, coulombic efficiency and rate performance compared to bare LNMO annealed at 500 °C when cycled at 3.4–4.9 V vs. Li/Li+. The improvements are probably due to suppressed Ni and Mn dissolution with Ti surface doping.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.108
Times cited: 9
DOI: 10.1039/C7RA12932G
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“Modelling molecular adsorption on charged or polarized surfaces: a critical flaw in common approaches”. Bal KM, Neyts EC, Physical chemistry, chemical physics 20, 8456 (2018). http://doi.org/10.1039/C7CP08209F
Abstract: A number of recent computational material design studies based on density functional theory (DFT) calculations have put forward a new class of materials with electrically switchable chemical characteristics that can be exploited in the development of tunable gas storage and electrocatalytic applications. We find systematic flaws in almost every computational study of gas adsorption on polarized or charged surfaces, stemming from an improper and unreproducible treatment of periodicity, leading to very large errors of up to 3 eV in some cases. Two simple corrective procedures that lead to consistent results are proposed, constituting a crucial course correction to the research in the field.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.123
Times cited: 8
DOI: 10.1039/C7CP08209F
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“Superconducting nanoribbon with a constriction : a quantum-confined Josephson junction”. Flammia L, Zhang L-F, Covaci L, Perali A, Milošević, MV, Physical review B 97, 134514 (2018). http://doi.org/10.1103/PHYSREVB.97.134514
Abstract: Extended defects are known to strongly affect nanoscale superconductors. Here, we report the properties of superconducting nanoribbons with a constriction formed between two adjacent step edges by solving the Bogoliubov-de Gennes equations self-consistently in the regime where quantum confinement is important. Since the quantum resonances of the superconducting gap in the constricted area are different from the rest of the nanoribbon, such constriction forms a quantum-confined S-S'-S Josephson junction, with a broadly tunable performance depending on the length and width of the constriction with respect to the nanoribbon, and possible gating. These findings provide an intriguing approach to further tailor superconducting quantum devices where Josephson effect is of use.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 7
DOI: 10.1103/PHYSREVB.97.134514
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“Chemistry of Shape-Controlled Iron Oxide Nanocrystal Formation”. Feld A, Weimer A, Kornowski A, Winckelmans N, Merkl J-P, Kloust H, Zierold R, Schmidtke C, Schotten T, Riedner M, Bals S, Weller PD Horst, ACS nano 13, 152 (2018). http://doi.org/10.1021/acsnano.8b05032
Abstract: Herein we demonstrate that meticulous and in-depth analysis of the reaction mechanisms of nanoparticle formation is rewarded by full control of size, shape and crystal structure of superparamagnetic iron oxide nanocrystals during synthesis. Starting from two iron sources – iron(II)- and iron(III) carbonate -a strict separation of oleate formation from the generation of reactive pyrolysis products and concomitant nucleation of iron oxide nanoparticles was achieved. This protocol enabled us to analyze each step of nanoparticle formation independently in depth. Progress of the entire reaction was monitored via matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) and gas chromatography (GC) gaining insight into the formation of various iron oleate species prior to nucleation. Interestingly, due to the intrinsic strongly reductive pyrolysis conditions of the oleate intermediates and redox process in early stages of the synthesis, pristine iron oxide nuclei were composed exclusively from wustite, irrespective of the oxidation state of the iron source. Controlling the reaction conditions provided a very broad range of size- and shape defined monodisperse iron oxide nanoparticles. Curiously, after nucleation star shaped nanocrystals were obtained, which underwent metamorphism towards cubic shaped particles. EELS tomography revealed ex post oxidation of the primary wustite nanocrystal providing a full 3D image of Fe2+ and Fe3+ distribution within. Overall, we developed a highly flexible synthesis, yielding multigram amounts of well-defined iron oxide nanocrystals of different sizes and morphologies.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 13.942
Times cited: 54
DOI: 10.1021/acsnano.8b05032
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“Disconnecting Symmetry Breaking from Seeded Growth for the Reproducible Synthesis of High Quality Gold Nanorods”. Gonzalez-Rubio G, Kumar V, Llombart P, Diaz-Nunez P, Bladt E, Altantzis T, Bals S, Pena-Rodriguez O, Noya EG, MacDowell LG, Guerrero-Martinez A, Liz-Marzan LM, ACS nano 13, 4424 (2019). http://doi.org/10.1021/ACSNANO.8B09658
Abstract: One of the major difficulties hindering the widespread application of colloidal anisotropic plasmonic nanoparticles is the limited robustness and reproducibility of multistep synthetic methods. We demonstrate herein that the reproducibility and reliability of colloidal gold nanorod (AuNR) synthesis can be greatly improved by disconnecting the symmetry-breaking event from the seeded growth process. We have used a modified silver-assisted seeded growth method in the presence of the surfactant hexadecyltrimethylammonium bromide and n-decanol as a co-surfactant to prepare small AuNRs in high yield, which were then used as seeds for the growth of high quality AuNR colloids. Whereas the use of n-decanol provides a more-rigid micellar system, the growth on anisotropic seeds avoids sources of irreproducibility during the symmetry breaking step, yielding uniform AuNR colloids with narrow plasmon bands, ranging from 600 to 1270 nm, and allowing the fine-tuning of the final dimensions. This method provides a robust route for the preparation of high quality AuNR colloids with tunable morphology, size, and optical response in a reproducible and scalable manner.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Applied Electrochemistry & Catalysis (ELCAT)
Impact Factor: 13.942
Times cited: 100
DOI: 10.1021/ACSNANO.8B09658
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“Rational design of an XNA ligase through docking of unbound nucleic acids to toroidal proteins”. Vanmeert M, Razzokov J, Mirza MU, Weeks SD, Schepers G, Bogaerts A, Rozenski J, Froeyen M, Herdewijn P, Pinheiro VB, Lescrinier E, Nucleic acids research 47, 7130 (2019). http://doi.org/10.1093/nar/gkz551
Abstract: Xenobiotic nucleic acids (XNA) are nucleic acid analogues not present in nature that can be used for the storage of genetic information. In vivo XNA applications could be developed into novel biocontainment strategies, but are currently limited by the challenge of developing XNA processing enzymes such as polymerases, ligases and nucleases. Here, we present a structure-guided modelling-based strategy for the rational design of those enzymes essential for the development of XNA molecular biology. Docking of protein domains to unbound double-stranded nucleic acids is used to generate a first approximation of the extensive interaction of nucleic acid processing enzymes with their substrate. Molecular dynamics is used to optimise that prediction allowing, for the first time, the accurate prediction of how proteins that form toroidal complexes with nucleic acids interact with their substrate. Using the Chlorella virus DNA ligase as a proof of principle, we recapitulate the ligase's substrate specificity and successfully predict how to convert it into an XNA-templated XNA ligase.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 10.162
Times cited: 1
DOI: 10.1093/nar/gkz551
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“Tailoring Cu+ for Ga3+ cation exchange in Cu2-xS and CuInS2 nanocrystals by controlling the Ga precursor chemistry”. Hinterding SOM, Berends AC, Kurttepeli M, Moret M-E, Meeldijk JD, Bals S, van der Stam W, de Donega CM, ACS nano 13, 12880 (2019). http://doi.org/10.1021/ACSNANO.9B05337
Abstract: Nanoscale cation exchange (CE) has resulted in colloidal nanomaterials that are unattainable by direct synthesis methods. Aliovalent CE is complex and synthetically challenging because the exchange of an unequal number of host and guest cations is required to maintain charge balance. An approach to control aliovalent CE reactions is the use of a single reactant to both supply the guest cation and extract the host cation. Here, we study the application of GaCl3-L complexes [L = trioctylphosphine (TOP), triphenylphosphite (TPP), diphenylphosphine (DPP)] as reactants in the exchange of Cu+ for Ga3+ in Cu2-xS nanocrystals. We find that noncomplexed GaCl3 etches the nanocrystals by S2- extraction, whereas GaCl3-TOP is unreactive. Successful exchange of Cu+ for Ga3+ is only possible when GaCl3 is complexed with either TPP or DPP. This is attributed to the pivotal role of the Cu2-xS-GaCl3-L activated complex that forms at the surface of the nanocrystal at the onset of the CE reaction, which must be such that simultaneous Ga3+ insertion and Cu+ extraction can occur. This requisite is only met if GaCl3 is bound to a phosphine ligand, with a moderate bond strength, to allow facile dissociation of the complex at the nanocrystal surface. The general validity of this mechanism is demonstrated by using GaCl3-DPP to convert CuInS2 into (Cu,Ga,In)S-2 nanocrystals, which increases the photoluminescence quantum yield 10 -fold, while blue -shifting the photoluminescence into the NIR biological window. This highlights the general applicability of the mechanistic insights provided by our work.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 13.942
Times cited: 27
DOI: 10.1021/ACSNANO.9B05337
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“Plasma-Based CH4Conversion into Higher Hydrocarbons and H2: Modeling to Reveal the Reaction Mechanisms of Different Plasma Sources”. Heijkers S, Aghaei M, Bogaerts A, Journal Of Physical Chemistry C 124, 7016 (2020). http://doi.org/10.1021/acs.jpcc.0c00082
Abstract: Plasma is gaining interest for CH4 conversion into higher hydrocarbons and H2. However, the performance in terms of conversion and selectivity toward different hydrocarbons is different for different plasma types, and the underlying mechanisms are not yet fully understood. Therefore, we study here these mechanisms in different plasma sources, by means of a chemical kinetics model. The model is first validated by comparing the calculated conversions and hydrocarbon/H2 selectivities with experimental results in these different plasma types and over a wide range of specific energy input (SEI) values. Our model predicts that vibrational−translational nonequilibrium is negligible in all CH4 plasmas investigated, and instead, thermal conversion is important. Higher gas temperatures also lead to a more selective production of unsaturated hydrocarbons (mainly C2H2) due to neutral dissociation of CH4 and subsequent dehydrogenation processes, while three-body recombination reactions into saturated hydrocarbons (mainly C2H6, but also higher hydrocarbons) are dominant in low temperature plasmas.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.7
DOI: 10.1021/acs.jpcc.0c00082
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“Metal-insulator transition of SrVO 3 ultrathin films embedded in SrVO 3 / SrTiO 3 superlattices”. Wang J, Gauquelin N, Huijben M, Verbeeck J, Rijnders G, Koster G, Applied Physics Letters 117, 133105 (2020). http://doi.org/10.1063/5.0020615
Abstract: The metal-insulator transition (MIT) in strongly correlated oxides is a topic of great interest for its potential applications, such as Mott field effect transistors and sensors. We report that the MIT in high quality epitaxial SrVO3 (SVO) thin films is present as the film thickness is reduced, lowering the dimensionality of the system, and electron-electron correlations start to become the dominant interactions. The critical thickness of 3 u.c is achieved by avoiding effects due to off-stoichiometry using optimal growth conditions and excluding any surface effects by a STO capping layer. Compared to the single SVO thin films, conductivity enhancement in SVO/STO superlattices is observed. This can be explained by the interlayer coupling effect between SVO sublayers in the superlattices. Magnetoresistance and Hall measurements indicate that the dominant driving force of MIT is the electron–electron interaction.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4
Times cited: 8
DOI: 10.1063/5.0020615
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“Single-layer Janus black arsenic-phosphorus (b-AsP): optical dichroism, anisotropic vibrational, thermal, and elastic properties”. Li LL, Bacaksiz C, Nakhaee M, Pentcheva R, Peeters FM, Yagmurcukardes M, Physical Review B 101, 134102 (2020). http://doi.org/10.1103/PHYSREVB.101.134102
Abstract: By using density functional theory (DFT) calculations, we predict a puckered, dynamically stable Janus single-layer black arsenic-phosphorus (b-AsP), which is composed of two different atomic sublayers, arsenic and phosphorus atoms. The calculated phonon spectrum reveals that Janus single-layer b-AsP is dynamically stable with either pure or coupled optical phonon branches arising from As and P atoms. The calculated Raman spectrum indicates that due to the relatively strong P-P bonds, As atoms have no contribution to the highfrequency optical vibrations. In addition, the orientation-dependent isovolume heat capacity reveals anisotropic contributions of LA and TA phonon branches to the low-temperature thermal properties. Unlike pristine single layers of b-As and b-P, Janus single-layer b-AsP exhibits additional out-of-plane asymmetry which leads to important consequences for its electronic, optical, and elastic properties. In contrast to single-layer b-As, Janus single-layer b-AsP is found to possess a direct band gap dominated by the P atoms. Moreover, real and imaginary parts of the dynamical dielectric function, including excitonic effects, reveal the highly anisotropic optical feature of the Janus single-layer. A tight-binding (TB) model is also presented for Janus single-layer b-AsP, and it is shown that, with up to seven nearest hoppings, the TB model reproduces well the DFT band structure in the low-energy region around the band gap. This TB model can be used in combination with the Green's function approach to study, e.g., quantum transport in finite systems based on Janus single-layer b-AsP. Furthermore, the linear-elastic properties of Janus single-layer b-AsP are investigated, and the orientation-dependent in-plane stiffness and Poisson ratio are calculated. It is found that the Janus single layer exhibits strong in-plane anisotropy in its Poisson ratio much larger than that of single-layer b-P. This Janus single layer is relevant for promising applications in optical dichroism and anisotropic nanoelasticity.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.7
Times cited: 39
DOI: 10.1103/PHYSREVB.101.134102
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