“Parity-fluctuation induced enlargement of the ratio \DeltaE/kBTc in metallic grains”. Croitoru MD, Shanenko AA, Peeters FM, Axt VM, Physical review : B : condensed matter and materials physics 84, 214518 (2011). http://doi.org/10.1103/PhysRevB.84.214518
Abstract: We investigate how the interplay of quantum confinement and particle number-parity fluctuations affects superconducting correlations in ultra-small metallic grains. Using the number-parity projected BCS formalism we calculate the critical temperature and the excitation gap as a function of the grain size for grains with even and odd number of confined carriers. We show that the experimentally observed anomalous increase of the coupling ratio ΔE/kBTc with decreasing superconducting grain size can be attributed to an enhancement of the number-parity fluctuations in ultra-small grains.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 14
DOI: 10.1103/PhysRevB.84.214518
|
“Phase-slip phenomena in NbN superconducting nanowires with leads”. Elmurodov AK, Peeters FM, Vodolazov DY, Michotte S, Adam S, de Menten de Horne F, Piraux L, Lucot D, Mailly D, Physical review : B : solid state 78, 214519 (2008). http://doi.org/10.1103/PhysRevB.78.214519
Abstract: Transport properties of a superconducting NbN nanowire are studied experimentally and theoretically. Different attached leads (superconducting contacts) allowed us to measure current-voltage (I-V) characteristics of different segments of the wire independently. The experimental results show that with increasing the length of the segment the number of jumps in the I-V curve increases indicating an increasing number of phase-slip phenomena. The system shows a clear hysteresis in the direction of the current sweep, the size of which depends on the length of the superconducting segment. The interpretation of the experimental results is supported by theoretical simulations that are based on the time-dependent Ginzburg-Landau theory, the heat equation has been included in the Ginzbur-Landau theory.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 27
DOI: 10.1103/PhysRevB.78.214519
|
“Polar and magnetic layered A-site and rock salt B-site-ordered NaLnFeWO6 (Ln = La, Nd) perovskites”. Retuerto M, Li MR, Ignatov A, Croft M, Ramanujachary KV, Chi S, Hodges JP, Dachraoui W, Hadermann J, Tran TT, Halasyamani PS, Grams CP, Hemberger J, Greenblatt M;, Inorganic chemistry 52, 12482 (2013). http://doi.org/10.1021/ic401491y
Abstract: We have expanded the double perovskite family of materials with the unusual combination of layered order in the A sublattice and rock salt order over the B sublattice to compounds NaLaFeWO6 and NaNdFeWO6. The materials have been synthesized and studied by powder X-ray diffraction, neutron diffraction, electron diffraction, magnetic measurements, X-ray absorption spectroscopy, dielectric measurements, and second harmonic generation. At room temperature, the crystal structures of both compounds can be defined in the noncentrosymmetric monoclinic P2(1) space group resulting from the combination of ordering both in the A and B sublattices, the distortion of the cell due to tilting of the octahedra, and the displacement of certain cations. The magnetic studies show that both compounds are ordered antiferromagnetically below T-N approximate to 25 K for NaLaFeWO6 and at similar to 21 K for NaNdFeWO6. The magnetic structure of NaNdFeWO6 has been solved with a propagation vector k = (1/2 0 1/2) as an antiferromagnetic arrangement of Fe and Nd moments. Although the samples are potential multiferroics, the dielectric measurements do not show a ferroelectric response.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 17
DOI: 10.1021/ic401491y
|
“Real-space characterization of short-range order in Cu-Pd alloys”. Rodewald M, Rodewald K, De Meulenaere P, Van Tendeloo G, Physical review : B : condensed matter and materials physics 55, 14173 (1997). http://doi.org/10.1103/PhysRevB.55.14173
Abstract: Cu-Pd alloys containing 10, 20, 30, 40, and 50 at. % Pd and quenched from a temperature just above the ordering temperature T-c are investigated by electron diffraction and high-resolution electron microscopy (HREM). The results show diffuse electron diffraction intensities at {100} and {110} positions for the alloy with 10 at. % Pd, but with a characteristic twofold and fourfold splitting for the alloys with more than 10 at. % Pd. High-resolution images show the formation of microdomains best developed between 20 and 30 at. % Pd. A real-space characterization has been performed by applying videographic real-structure simulations revealing that the splitting of the diffuse maxima depends on the average distance between microdomains of Cu3Au type in antiphase with each other. By applying image processing routines on the HREM images, correlation vectors are identified which correspond to correlations between microdomains.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 15
DOI: 10.1103/PhysRevB.55.14173
|
“Second-order multiple-quanta flux entry into a perforated spherical mesoscopic superconductor”. Xu B, Milošević, MV, Peeters FM, Physical review : B : condensed matter and materials physics 82, 214501 (2010). http://doi.org/10.1103/PhysRevB.82.214501
Abstract: Flux entry in type-II superconductors without prominent symmetry is a first-order phase transition, where flux enters conventionally gradual in units of a flux quantum. Here we show that neither is necessarily the case in a mesoscopic superconducting sphere with a perforation. In axially applied magnetic field, vortices initially occupy the hole, and can oppose further flux entry in the sample. As a result, multiple-quanta flux entry is found at significantly higher field, and it can manifest as a second-order transition due to suppressed geometric barrier at the equatorial belt of the sample. At high fields a new state is found, with gradually destroyed condensate from the equator inwards, the exact opposite of surface superconductivity.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 2
DOI: 10.1103/PhysRevB.82.214501
|
“Short-range order of Br and three-dimensional magnetism in (CuBr)LaNb2O7”. Tsirlin AA, Abakumov AM, Ritter C, Henry PF, Janson O, Rosner H, Physical review : B : condensed matter and materials physics 85, 214427 (2012). http://doi.org/10.1103/PhysRevB.85.214427
Abstract: We present a comprehensive study of the crystal structure, magnetic structure, and microscopic magnetic model of (CuBr)LaNb2O7, the Br analog of the spin-gap quantum magnet (CuCl) LaNb2O7. Despite similar crystal structures and spin lattices, the magnetic behavior and even peculiarities of the atomic arrangement in the Cl and Br compounds are very different. The high- resolution x-ray and neutron data reveal a split position of Br atoms in (CuBr) LaNb2O7. This splitting originates from two possible configurations developed by [CuBr] zigzag ribbons. While the Br atoms are locally ordered in the ab plane, their arrangement along the c direction remains partially disordered. The predominant and energetically more favorable configuration features an additional doubling of the c lattice parameter that was not observed in (CuCl) LaNb2O7. (CuBr) LaNb2O7 undergoes long-range antiferromagnetic ordering at T-N = 32 K, which is nearly 70% of the leading exchange coupling J4 similar or equal to 48 K. The Br compound does not show any experimental signatures of low-dimensional magnetism because the underlying spin lattice is three-dimensional. The coupling along the c direction is comparable to the couplings in the ab plane, even though the shortest Cu-Cu distance along c (11.69 angstrom) is three times larger than nearest-neighbor distances in the ab plane (3.55 angstrom). The stripe antiferromagnetic long-range order featuring columns of parallel spins in the ab plane and antiparallel spins along c is verified experimentally and confirmed by the microscopic analysis.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 5
DOI: 10.1103/PhysRevB.85.214427
|
“Spin- and valley-dependent commensurability oscillations and electric-field-induced quantum Hall plateaux in periodically modulated silicene”. Shakouri K, Vasilopoulos P, Vargiamidis V, Hai G-Q, Peeters FM, Applied physics letters 104, 213109 (2014). http://doi.org/10.1063/1.4878509
Abstract: We study the commensurability oscillations in silicene subject to a perpendicular electric field E-z, a weak magnetic field B, and a weak periodic potential V = V-0 cos(Cy); C = 2 pi/a(0) with a(0) its period. The field E-z and/or the modulation lift the spin degeneracy of the Landau levels and lead to spin and valley resolved Weiss oscillations. The spin resolution is maximal when the field E-z is replaced by a periodic one E-z = E-0 cos(Dy); D = 2 pi/b(0), while the valley one is maximal for b(0) = a(0). In certain ranges of B values, the current is fully spin or valley polarized. Additional quantum Hall conductivity plateaux arise due to spin and valley intra-Landau-level transitions. (C) 2014 AIP Publishing LLC.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.411
Times cited: 16
DOI: 10.1063/1.4878509
|
“Spiral ground state against ferroelectricity in the frustrated magnet BiMnFe2O6”. Abakumov AM, Tsirlin AA, Perez-Mato JM, Petřiček V, Rosner H, Yang T, Greenblatt M, Physical review : B : condensed matter and materials physics 83, 214402 (2011). http://doi.org/10.1103/PhysRevB.83.214402
Abstract: The spiral magnetic structure and underlying spin lattice of BiMnFe2O6 are investigated by low-temperature neutron powder diffraction and density functional theory band structure calculations. In spite of the random distribution of the Mn3+ and Fe3+ cations, this centrosymmetric compound undergoes a transition into an incommensurate antiferromagnetically ordered state below TN≃220 K. The magnetic structure is characterized by the propagation vector k=[0,β,0] with β≃0.14 and the P221211′(0β0)0s0s magnetic superspace symmetry. It comprises antiferromagnetic helixes propagating along the b axis. The magnetic moments lie in the ac plane and rotate about π(1+β)≃204.8-deg angle between the adjacent magnetic atoms along b. The spiral magnetic structure arises from the peculiar frustrated arrangement of exchange couplings in the ab plane. The antiferromagnetic coupling along the c axis cancels the possible electric polarization and prevents ferroelectricity in BiMnFe2O6.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 12
DOI: 10.1103/PhysRevB.83.214402
|
“Topological confinement in graphene bilayer quantum rings”. Xavier LJP, Pereira JM, Chaves A, Farias GA, Peeters FM, Applied physics letters 96, 212108 (2010). http://doi.org/10.1063/1.3431618
Abstract: We find localized electron and hole states in a ring-shaped potential kink in biased bilayer graphene. Within the continuum description, we show that for sharp potential steps the Dirac equation describing carrier states close to the K (or K′) point of the first Brillouin zone can be solved analytically for a circular kink/antikink dot. The solutions exhibit interfacial states which exhibit AharonovBohm oscillations as functions of the height of the potential step and/or the radius of the ring.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.411
Times cited: 29
DOI: 10.1063/1.3431618
|
“Tunable kinematics of phase-slip lines in a superconducting stripe with magnetic dots”. Berdiyorov GR, Milošević, MV, Peeters FM, Physical review : B : solid state 80, 214509 (2009). http://doi.org/10.1103/PhysRevB.80.214509
Abstract: Using numerical simulations, we study the dynamic properties of a superconducting stripe with a perpendicular magnetized ferromagnet on top in the presence of an applied dc current. In the resistive state conventional phase-slip lines are transformed into kinematic vortex-antivortex pairs with special dynamic behavior. In addition, the location of phase slippage in the sample is predetermined by the position of the magnetic dot. Both these effects directly influence the dynamics of the superconducting condensate and lead to periodic oscillations of the voltage across the sample with a frequency tunable both by the applied current and by the magnetization of the magnet. We found that the frequency of the voltage oscillations increases with increasing number of magnetic dots.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 33
DOI: 10.1103/PhysRevB.80.214509
|
“Vortex matter in mesoscopic two-gap superconducting disks: influence of Josephson and magnetic coupling”. Geurts R, Milošević, MV, Peeters FM, Physical review : B : condensed matter and materials physics 81, 15 (2010). http://doi.org/10.1103/PhysRevB.81.214514
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 89
DOI: 10.1103/PhysRevB.81.214514
|
“One-pot synthesis of carbon-coated nanostructured iron oxide on few-layer graphene for lithium-ion batteries”. Sun Z, Madej E, Wiktor, Sinev I, Fischer RA, Van Tendeloo G, Muhler M, Schuhmann W, Ventosa E, Chemistry: a European journal 21, 16154 (2015). http://doi.org/10.1002/chem.201501935
Abstract: Nanostructure engineering has been demonstrated to improve the electrochemical performance of iron oxide based electrodes in Li-ion batteries (LIBs). However, the synthesis of advanced functional materials often requires multiple steps. Herein, we present a facile one-pot synthesis of carbon-coated nanostructured iron oxide on few-layer graphene through high-pressure pyrolysis of ferrocene in the presence of pristine graphene. The ferrocene precursor supplies both iron and carbon to form the carbon-coated iron oxide, while the graphene acts as a high-surface-area anchor to achieve small metal oxide nanoparticles. When evaluated as a negative-electrode material for LIBs, our composite showed improved electrochemical performance compared to commercial iron oxide nanopowders, especially at fast charge/discharge rates.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 5.317
Times cited: 8
DOI: 10.1002/chem.201501935
|
“Pinning of magnetic skyrmions in a monolayer Co film on Pt(111) : Theoretical characterization and exemplified utilization”. Stosic D, Ludermir TB, Milošević, MV, Physical review B 96, 214403 (2017). http://doi.org/10.1103/PHYSREVB.96.214403
Abstract: <script type='text/javascript'>document.write(unpmarked('Magnetic skyrmions are nanoscale windings of the spin structure that can be observed in chiral magnets and hold promise for potential applications in storing or processing information. Pinning due to ever-present material imperfections crucially affects the mobility of skyrmions. Therefore, a proper understanding of how magnetic skyrmions pin to defects is necessary for the development and performance of spintronic devices. Here we present a fundamental analysis on the interactions of single skyrmions with atomic defects of distinctly different origins, in a Co monolayer on Pt, based on minimum-energy paths considerations and atomic-spin simulations. We first report the preferred pinning loci of the skyrmion as a function of its nominal size and the type of defect being considered, to further reveal the manipulation and \u0022breathing\u0022 of skyrmion core in the vicinity of a defect. We also show the behavior of skyrmions in the presence of an extended defect of particular geometry, that can lead to ratcheted skyrmion motion or a facilitated guidance on a defect \u0022trail.\u0022 We close the study with reflections on the expected thermal stability of the skyrmion against collapse on itself for a given nature of the defect, and discuss the applications where control of skyrmions by defects is of particular interest.'));
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 52
DOI: 10.1103/PHYSREVB.96.214403
|
“Fano resonances in bilayer phosphorene nanoring”. Zhang R, Wu Z, Li XJ, Li LL, Chen Q, Li Y-M, Peeters FM, Nanotechnology 29, 215202 (2018). http://doi.org/10.1088/1361-6528/AAB534
Abstract: Tunable transport properties and Fano resonances are predicted in a circular bilayer phosphorene nanoring. The conductance exhibits Fano resonances with varying incident energy and applied perpendicular magnetic field. These Fano resonance peaks can be accurately fitted with the well known Fano curves. When a magnetic field is applied to the nanoring, the conductance oscillates periodically with magnetic field which is reminiscent of the Aharonov-Bohm effect. Fano resonances are tightly related to the discrete states in the central nanoring, some of which are tunable by the magnetic field.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 3.44
Times cited: 4
DOI: 10.1088/1361-6528/AAB534
|
“Graphene quantum blisters : a tunable system to confine charge carriers”. Abdullah HM, Van der Donck M, Bahlouli H, Peeters FM, Van Duppen B, Applied physics letters 112, 213101 (2018). http://doi.org/10.1063/1.5023896
Abstract: Due to Klein tunneling, electrostatic confinement of electrons in graphene is not possible. This hinders the use of graphene for quantum dot applications. Only through quasi-bound states with finite lifetime has one achieved to confine charge carriers. Here, we propose that bilayer graphene with a local region of decoupled graphene layers is able to generate bound states under the application of an electrostatic gate. The discrete energy levels in such a quantum blister correspond to localized electron and hole states in the top and bottom layers. We find that this layer localization and the energy spectrum itself are tunable by a global electrostatic gate and that the latter also coincides with the electronic modes in a graphene disk. Curiously, states with energy close to the continuum exist primarily in the classically forbidden region outside the domain defining the blister. The results are robust against variations in size and shape of the blister which shows that it is a versatile system to achieve tunable electrostatic confinement in graphene. Published by AIP Publishing.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.411
Times cited: 9
DOI: 10.1063/1.5023896
|
“Magneto-polarons in monolayer transition-metal dichalcogenides”. Chen Q, Wang W, Peeters FM, Journal of applied physics 123, 214303 (2018). http://doi.org/10.1063/1.5025907
Abstract: Landau levels (LLs) are modified by the Frohlich interaction which we investigate within the improved Wigner-Brillouin theory for energies both below and above the longitudinal-optical-continuum in monolayer MoS2.., WS2, MoSe2, and WSe2. Polaron corrections to the LLs are enhanced in monolayer MoS2 as compared to WS2. A series of levels are found at h omega(LO) + lh omega(c), and in addition, the Frohlich interaction lifts the degeneracy between the levels nh omega(c) and h omega(LO) + lh omega(c) resulting in an anticrossing. The screening effect due to the environment plays an important role in the polaron energy corrections, which are also affected by the effective thickness r(eff) parameter. The polaron anticrossing energy gap E-gap decreases with increasing effective thickness r(eff). Published by AIP Publishing.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.068
Times cited: 19
DOI: 10.1063/1.5025907
|
“Exsolution of SrO during the Topochemical Conversion of LaSr3CoRuO8to the Oxyhydride LaSr3CoRuO4H4”. Jin L, Batuk M, Kirschner FKK, Lang F, Blundell SJ, Hadermann J, Hayward MA, Inorganic chemistry 58, 14863 (2019). http://doi.org/10.1021/acs.inorgchem.9b02552
Abstract: Reaction of the n = 1 Ruddlesden-Popper oxide LaSr3CoRuO8 with CaH2 yields the oxyhydride phase LaSr3CoRuO4H4 via topochemical anion-exchange. Close inspection of X-ray and neutron powder diffraction data in combination with HAADF-STEM images reveals that nanoparticles of SrO are exsolved from the system during the reaction, with the change in cation stoichiometry accommodated by the inclusion of n > 1 (Co/Ru)nOn+1H2n ‘perovskite’ layers into the Ruddlesden-Popper stacking sequence. This novel pseudo-topochemical process offers a new route for the formation of n > 1 Ruddlesden-Popper structured materials. Magnetization data are consistent with a LaSr3Co1+Ru2+O4H4 (Co1+, d8, S = 1; Ru2+, d6, S = 0) oxidation/spin state combination. Neutron diffraction and μ+SR data show no evidence for long-range magnetic order down to 2 K, suggesting the diamagnetic Ru2+ centers impede the Co-Co magnetic exchange interactions.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 1
DOI: 10.1021/acs.inorgchem.9b02552
|
“Degradation process of lead chromate in paintings by Vincent van Gogh studied by means of spectromicroscopic methods : part 5 : effects of nonoriginal surface coatings into the nature and distribution of chromium and sulfur species in chrome yellow paints”. Monico L, Janssens K, Vanmeert F, Cotte M, Brunetti BG, van der Snickt G, Leeuwestein M, Plisson JS, Menu M, Miliani C, Analytical chemistry 86, 10804 (2014). http://doi.org/10.1021/AC502841G
Abstract: The darkening of lead chromate yellow pigments, caused by a reduction of the chromate ions to Cr(III) compounds, is known to affect the appearance of several paintings by Vincent van Gogh. In previous papers of this series, we demonstrated that the darkening is activated by light and depends on the chemical composition and crystalline structure of the pigments. In this work, the results of Part 2 are extended and complemented with a new study aimed at deepening the knowledge of the nature and distribution of Cr and S species at the interface between the chrome yellow paint and the nonoriginal coating layer. For this purpose, three microsamples from two varnished paintings by Van Gogh and a waxed low relief by Gauguin (all originally uncoated) have been examined. Because nonoriginal coatings are often present in artwork by Van Gogh and contemporaries, the understanding of whether or not their application has influenced the morphological and/or physicochemical properties of the chrome yellow paint underneath is relevant in view of the conservation of these masterpieces. In all the samples studied, microscopic X-ray fluorescence (mu-XRF) and X-ray absorption near edge structure (mu-XANES) investigations showed that Cr(III)-based alteration products are present in the form of grains inside the coating (generally enriched of S species) and also homogeneously widespread at the paint surface. The distribution of Cr(III) species may be explained by the mechanical friction caused by the coating application by brush that picked up and redistributed the superficial Cr compounds, likely already present in the reduced state as result of the photodegradation process. The analysis of the XANES profiles allowed us to obtain new insights into the nature of the Cr(III) alteration products, that were identified as sulfate-, oxide-, organo-metal-, and chloride-based compounds. Building upon the knowledge acquired through the examination of original paint samples and from the investigation of aged model paints in the last Part 4 paper, in this study we aim to characterize a possible relation between the chemical composition of the coating and the chrome yellow degradation pathways by studying photochemically aged model samples covered with a dammar varnish contaminated with sulfide and sulfate salts. Cr speciation results did not show any evidence of the active role of the varnish and added S species on the reduction process of chrome yellows.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 6.32
Times cited: 25
DOI: 10.1021/AC502841G
|
“Microwave-assisted synthesis of mesoporous titania with increased crystallinity, specific surface area, and photocatalytic activity”. Meire M, Verbruggen SW, Lenaerts S, Lommens P, Van Der Voort P, Van Driessche I, Journal of materials science 51, 9822 (2016). http://doi.org/10.1007/S10853-016-0215-Y
Abstract: Mesoporous titanium dioxide is a material finding its use in a wide range of applications. For many of these, it is important to achieve a high degree of crystallinity in the material. It is generally accepted that the use of the soft templating approach to synthesize mesoporous titania, results in a compromise between crystallinity and specific surface area due to thermal instability of the used templates. In this paper, we explore how the use of microwave irradiation can influence the crystallinity, specific surface area, and the electronic properties of mesoporous titania. Therefore, we combined microwave radiation with an evaporation-induced self-assembly (EISA) synthesis. We show that additional microwave treatment at carefully chosen synthesis steps can enhance the crystallinity with 20 % without causing significant loss of surface area (>360 m2/g). Surface photovoltage measurements were used to investigate the electronic properties. The photocatalytic activity of the samples was evaluated in aqueous media by following the degradation of an industrial dye, methylene blue, and the herbicide isoproturon under UV irradiation and in gaseous media looking at the degradation of acetaldehyde, a common indoor pollutant under UVA irradiation. In all cases, the microwave treatment results in more active materials.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 2.599
Times cited: 8
DOI: 10.1007/S10853-016-0215-Y
|
“A multi-objective optimization-extended techno-economic assessment : exploring the optimal microalgal-based value chain”. Thomassen G, Van Dael M, You F, Van Passel S, Green Chemistry 21, 5945 (2019). http://doi.org/10.1039/C9GC03071A
Abstract: The use of fossil-based products induces a large environmental burden. To lighten this burden, green technologies are required that can replace their fossil-based counterparts. To enable the development of economically viable green technologies, an optimization towards both economic and environmental objectives is required. To perform this multi-objective optimization (MOO), the environmental techno-economic assessment (ETEA) methodology is extended towards a MOO-extended ETEA. The development of this MOO-extended ETEA is the main objective of this manuscript. As an example of a green technology, the concept of microalgae biorefineries is used as a case study to illustrate the MOO-extended ETEA. According to the results, all optimal value chains include open pond cultivation, a membrane for medium recycling and spray drying. The optimal economic value chain uses Nannochloropsis sp. in a one-stage cultivation to produce fish larvae feed, while the optimal environmental design uses Dunaliella salina or Haematococcus pluvialis to produce carotenoids and fertilizer or energy products, by means of anaerobic digestion or gasification. The crucial parameters for both environmental and economic feasibility are the content, price and reference impact of the main end product, the growth parameters and the biomass and carotenoid recovery efficiency alongside the different process steps. By identifying the economic and environmentally optimal algal-based value chain and the crucial drivers, the MOO-extended ETEA provides insights on how algae-based value chains can be developed in the most economic and environmentally-friendly way. For example, the inclusion of a medium recycling step to lower the water and salt consumption is required in all Pareto-optimal scenarios. Another major insight is the requirement of high-value products such as carotenoids or specialty food to obtain and economically and environmentally feasible algal-based value chain. Due to the modular nature of the MOO-extended ETEA, multiple processes can be included or excluded from the superstructure. Although this case study is limited to current microalgae biorefinery technologies, the MOO-extended ETEA can also be used to assess the economic and environmental effect of more innovative technologies. This way, the MOO-extended ETEA provides a methodology to assess the economic and environmental potential of innovative green technologies and shorten their time-to-market.
Keywords: A1 Journal article; Economics; Engineering sciences. Technology; Engineering Management (ENM)
Impact Factor: 9.125
Times cited: 1
DOI: 10.1039/C9GC03071A
|
“Two-dimensional carbon nitride (2DCN) nanosheets : tuning of novel electronic and magnetic properties by hydrogenation, atom substitution and defect engineering”. Bafekry A, Shayesteh SF, Peeters FM, Journal of applied physics 126, 215104 (2019). http://doi.org/10.1063/1.5120525
Abstract: By employing first-principles calculations within the framework of density functional theory, we investigated the structural, electronic, and magnetic properties of graphene and various two-dimensional carbon-nitride (2DNC) nanosheets. The different 2DCN gives rise to diverse electronic properties such as metals (C3N2), semimetals (C4N and C9N4), half-metals (C4N3), ferromagnetic-metals (C9N7), semiconductors (C2N, C3N, C3N4, C6N6, and C6N8), spin-glass semiconductors (C10N9 and C14N12), and insulators (C2N2). Furthermore, the effects of adsorption and substitution of hydrogen atoms as well as N-vacancy defects on the electronic and magnetic properties are systematically studied. The introduction of point defects, including N vacancies, interstitial H impurity into graphene and different 2DCN crystals, results in very different band structures. Defect engineering leads to the discovery of potentially exotic properties that make 2DCN interesting for future investigations and emerging technological applications with precisely tailored properties. These properties can be useful for applications in various fields such as catalysis, energy storage, nanoelectronic devices, spintronics, optoelectronics, and nanosensors. Published under license by AIP Publishing.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.068
Times cited: 70
DOI: 10.1063/1.5120525
|
“Spin textures in chiral magnetic monolayers with suppressed nearest-neighbor exchange”. Menezes RM, de Souza Silva CC, Milošević, MV, Physical Review B 101, 214429 (2020). http://doi.org/10.1103/PHYSREVB.101.214429
Abstract: High tunability of two-dimensional magnetic materials (by strain, gating, heterostructuring, or otherwise) provides unique conditions for studying versatile magnetic properties and controlling emergent magnetic phases. Expanding the scope of achievable magnetic phenomena in such materials is important for both fundamental and technological advances. Here we perform atomistic spin-dynamics simulations to explore the (chiral) magnetic phases of atomic monolayers in the limit of suppressed first-neighbors exchange interaction. We report the rich phase diagram of exotic magnetic configurations, obtained for both square and honeycomb lattice symmetries, comprising coexistence of ferromagnetic and antiferromagnetic spin cycloids, as well as multiple types of magnetic skyrmions. We perform a minimum-energy path analysis for the skyrmion collapse to evaluate the stability of such topological objects and reveal that magnetic monolayers could be good candidates to host the antiferromagnetic skyrmions that are experimentally evasive to date.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.7
Times cited: 1
DOI: 10.1103/PHYSREVB.101.214429
|
“Machine learning approach to constructing tight binding models for solids with application to BiTeCl”. Nakhaee M, Ketabi SA, Peeters FM, Journal Of Applied Physics 128, 215107 (2020). http://doi.org/10.1063/5.0023980
Abstract: Finding a tight-binding (TB) model for a desired solid is always a challenge that is of great interest when, e.g., studying transport properties. A method is proposed to construct TB models for solids using machine learning (ML) techniques. The approach is based on the LCAO method in combination with Slater-Koster (SK) integrals, which are used to obtain optimal SK parameters. The lattice constant is used to generate training examples to construct a linear ML model. We successfully used this method to find a TB model for BiTeCl, where spin-orbit coupling plays an essential role in its topological behavior.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.2
Times cited: 10
DOI: 10.1063/5.0023980
|
“Magnetic Ordering in the Layered Cr(II) Oxide Arsenides Sr2CrO2Cr2As2and Ba2CrO2Cr2As2”. Xu X, Jones MA, Cassidy SJ, Manuel P, Orlandi F, Batuk M, Hadermann J, Clarke SJ, Inorganic Chemistry 59, 15898 (2020). http://doi.org/10.1021/acs.inorgchem.0c02415
Abstract: Sr2CrO2Cr2As2 and Ba2CrO2Cr2As2 with Cr2+ ions in CrO2 sheets and in CrAs layers crystallize with the Sr2Mn3Sb2O2 structure (space group I4/mmm, Z = 2) and lattice parameters a = 4.00800(2) Å, c = 18.8214(1) Å (Sr2CrO2Cr2As2) and a = 4.05506(2) Å, c = 20.5637(1) Å (Ba2CrO2Cr2As2) at room temperature. Powder neutron diffraction reveals checkerboard-type antiferromagnetic ordering of the Cr2+ ions in the arsenide layers below TN1Sr, of 600(10) K (Sr2CrO2Cr2As2) and TN1Ba 465(5) K (Ba2CrO2Cr2As2) with the moments initially directed perpendicular to the layers in both compounds. Checkerboard-type antiferromagnetic ordering of the Cr2+ ions in the oxide layer below 230(5) K for Ba2CrO2Cr2As2 occurs with these moments also perpendicular to the layers, consistent with the orientation preferences of d4 moments in the two layers. In contrast, below 330(5) K in Sr2CrO2Cr2As2, the oxide layer Cr2+ moments are initially oriented in the CrO2 plane; but on further cooling, these moments rotate to become perpendicular to the CrO2 planes, while the moments in the arsenide layers rotate by 90° with the moments on the two sublattices remaining orthogonal throughout [behavior recently reported independently by Liu et al. [Liu et al. Phys. Rev. B 2018, 98, 134416]]. In Sr2CrO2Cr2As2, electron diffraction and high resolution powder X-ray diffraction data show no evidence for a structural distortion that would allow the two Cr2+ sublattices to couple, but high resolution neutron powder diffraction data suggest a small incommensurability between the magnetic structure and the crystal structure, which may account for the coupling of the two sublattices and the observed spin reorientation. The saturation values of the Cr2+ moments in the CrO2 layers (3.34(1) μB (for Sr2CrO2Cr2As2) and 3.30(1) μB (for Ba2CrO2Cr2As2)) are larger than those in the CrAs layers (2.68(1) μB for Sr2CrO2Cr2As2 and 2.298(8) μB for Ba2CrO2Cr2As2) reflecting greater covalency in the arsenide layers.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.6
DOI: 10.1021/acs.inorgchem.0c02415
|
“Two-dimensional carbon nitride C₆N nanosheet with egg-comb-like structure and electronic properties of a semimetal”. Bafekry A, Shahrokhi M, Shafique A, Jappor HR, Shojaei F, Feghhi SAH, Ghergherehchi M, Gogova D, Nanotechnology 32, 215702 (2021). http://doi.org/10.1088/1361-6528/ABD50C
Abstract: In this study, the structural, electronic and optical properties of theoretically predicted C6N monolayer structure are investigated by means of Density Functional Theory-based First-Principles Calculations. Phonon band dispersion calculations and molecular dynamics simulations reveal the dynamical and thermal stability of the C6N single-layer structure. We found out that the C6N monolayer has large negative in-plane Poisson's ratios along both X and Y direction and the both values are almost four times that of the famous-pentagraphene. The electronic structure shows that C6N monolayer is a semi-metal and has a Dirac-point in the BZ. The optical analysis using the random phase approximation method constructed over HSE06 illustrates that the first peak of absorption coefficient of the C6N monolayer along all polarizations is located in the IR range of spectrum, while the second absorption peak occurs in the visible range, which suggests its potential applications in optical and electronic devices. Interestingly, optically anisotropic character of this system is highly desirable for the design of polarization-sensitive photodetectors. Thermoelectric properties such as Seebeck coefficient, electrical conductivity, electronic thermal conductivity and power factor are investigated as a function of carrier doping at temperatures 300, 400, and 500 K. In general, we predict that the C6N monolayer could be a new platform for study of novel physical properties in two-dimensional semi-metal materials, which may provide new opportunities to realize high-speed low-dissipation devices.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 3.44
DOI: 10.1088/1361-6528/ABD50C
|
“First-principles investigation of electronic, mechanical and thermoelectric properties of graphene-like XBi (X = Si, Ge, Sn) monolayers”. Bafekry A, Yagmurcukardes M, Akgenc B, Ghergherehchi M, Mortazavi B, Physical Chemistry Chemical Physics 23, 12471 (2021). http://doi.org/10.1039/D1CP01183A
Abstract: Research progress on single layer group III monochalcogenides has been increasing rapidly owing to their interesting physics. Herein, we investigate the dynamically stable single layer forms of XBi (X = Ge, Si or Sn) using density functional theory calculations. Phonon band dispersion calculations and ab initio molecular dynamics simulations reveal the dynamical and thermal stability of the considered monolayers. Raman spectra calculations indicate the existence of 5 Raman active phonon modes, 3 of which are prominent and can be observed in possible Raman measurements. The electronic band structures of the XBi single layers were investigated with and without the effects of spin-orbit coupling (SOC). Our results show that XBi single layers show semiconducting properties with narrow band gap values without SOC. However, only single layer SiBi is an indirect band gap semiconductor, while GeBi and SnBi exhibit metallic behaviors when adding spin-orbit coupling effects. In addition, the calculated linear elastic parameters indicate the soft nature of the predicted monolayers. Moreover, our predictions for the thermoelectric properties of single layer XBi reveal that SiBi is a good thermoelectric material with increasing temperature. Overall, it is proposed that single layer XBi structures can be alternative, stable 2D single layers with varying electronic and thermoelectric properties.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 4.123
DOI: 10.1039/D1CP01183A
|
“Two-dimensional buckled tetragonal cadmium chalcogenides including CdS, CdSe, and CdTe monolayers as photo-catalysts for water splitting”. Naseri M, Bafekry A, Faraji M, Hoat DM, Fadlallah MM, Ghergherehchi M, Sabbaghi N, Gogova D, Physical Chemistry Chemical Physics 23, 12226 (2021). http://doi.org/10.1039/D1CP00317H
Abstract: Pure hydrogen production via water splitting is an ideal strategy for producing clean and sustainable energy. Two-dimensional (2D) cadmium chalcogenide single-layers with a tetragonal crystal structure, namely Tetra-CdX (X = S, Se, and Te) monolayers, are theoretically predicted by means of density functional theory (DFT). Their structural stability and electronic and optical properties are investigated. We find that Tetra-CdX single-layers are thermodynamically stable. Their stability decreases as we go down the 6A group in the periodic table, i.e., from X = S to Se, and Te which also means that the electronegativity decreases. All considered novel monolayers are indirect band gap semiconductors. Using the HSE06 functional the electronic band gaps of CdS, CdSe, and CdTe monolayers are predicted to be 3.10 eV, 2.97 eV, and 2.90 eV, respectively. The impact of mechanical strain on the physical properties was studied, which indicates that compressive strain increases the band gap and tensile strain decreases the band gap. The optical properties of the Tetra-CdX monolayers show the ability of these monolayers to absorb visible light. Due to the suitable band gaps and band edge positions of Tetra-CdX, these newly discovered 2D materials are promising for photocatalytic water splitting.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 4.123
DOI: 10.1039/D1CP00317H
|
“Distinctive g-factor of Moire-confined excitons in van der Waals heterostructures”. Gobato YG, de Brito CS, Chaves A, Prosnikov MA, Wozniak T, Guo S, Barcelos ID, Milošević, MV, Withers F, Christianen PCM, Nano letters 22, 8641 (2022). http://doi.org/10.1021/ACS.NANOLETT.2C03008
Abstract: We investigated the valley Zeeman splitting of excitonic peaks in the microphotoluminescence (mu PL) spectra of high-quality hBN/WS2/MoSe2/hBN heterostructures under perpendicular magnetic fields up to 20 T. We identify two neutral exciton peaks in the mu PL spectra; the lower-energy peak exhibits a reduced g-factor relative to that of the higher energy peak and much lower than the recently reported values for interlayer excitons in other van der Waals (vdW) heterostructures. We provide evidence that such a discernible g-factor stems from the spatial confinement of the exciton in the potential landscape created by the moire pattern due to lattice mismatch or interlayer twist in heterobilayers. This renders magneto-mu PL an important tool to reach a deeper understanding of the effect of moire patterns on excitonic confinement in vdW heterostructures.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 10.8
Times cited: 3
DOI: 10.1021/ACS.NANOLETT.2C03008
|
“Efficient Ab initio modeling of dielectric screening in 2D van der Waals materials : including phonons, substrates, and doping”. Gjerding MN, Cavalcante LSR, Chaves A, Thygesen KS, Journal Of Physical Chemistry C 124, 11609 (2020). http://doi.org/10.1021/ACS.JPCC.0C01635
Abstract: The quantum electrostatic heterostructure (QEH) model allows for efficient computation of the dielectric screening properties of layered van der Waals (vdW)-bonded heterostructures in terms of the dielectric functions of the individual two-dimensional (2D) layers. Here, we extend the QEH model by including (1) contributions to the dielectric function from infrared active phonons in the 2D layers, (2) screening from homogeneous bulk substrates, and (3) intraband screening from free carriers in doped 2D semiconductor layers. We demonstrate the potential of the extended QEH model by calculating the dispersion of coupled phonons in multilayer stacks of hexagonal boron-nitride (hBN), the strong hybridization of plasmons and optical phonons in graphene/hBN heterostructures, the effect of substrate screening on the exciton series of monolayer MoS2, and the properties of hyperbolic plasmons in a doped phosphorene sheet. The new QEH code is distributed as a Python package with a simple command line interface and a comprehensive library of dielectric building blocks for the most common 2D materials, providing an efficient open platform for dielectric modeling of realistic vdW heterostructures.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 3.7
DOI: 10.1021/ACS.JPCC.0C01635
|
“Valley filtering in graphene due to substrate-induced mass potential”. da Costa DR, Chaves A, Farias GA, Peeters FM, Journal of physics : condensed matter 29, 215502 (2017). http://doi.org/10.1088/1361-648X/AA6B24
Abstract: The interaction of monolayer graphene with specific substrates may break its sublattice symmetry and results in unidirectional chiral states with opposite group velocities in the different Dirac cones (Zarenia et al 2012 Phys. Rev. B 86 085451). Taking advantage of this feature, we propose a valley filter based on a transversal mass kink for low energy electrons in graphene, which is obtained by assuming a defect region in the substrate that provides a change in the sign of the substrate-induced mass and thus creates a non-biased channel, perpendicular to the kink, for electron motion. By solving the time-dependent Schrodinger equation for the tight-binding Hamiltonian, we investigate the time evolution of a Gaussian wave packet propagating through such a system and obtain the transport properties of this graphene-based substrate-induced quantum point contact. Our results demonstrate that efficient valley filtering can be obtained, provided: (i) the electron energy is sufficiently low, i.e. with electrons belonging mostly to the lowest sub-band of the channel, and (ii) the channel length (width) is sufficiently long (narrow). Moreover, even though the transmission probabilities for each valley are significantly affected by impurities and defects in the channel region, the valley polarization in this system is shown to be robust against their presence.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Times cited: 15
DOI: 10.1088/1361-648X/AA6B24
|