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“Electron and hole states in diluted magnetic semiconductor quantum dots”. Chang K, Li SS, Xia JB, Peeters FM, Physical review : B : condensed matter and materials physics 69, 235203 (2004). http://doi.org/10.1103/PhysRevB.69.235203
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 32
DOI: 10.1103/PhysRevB.69.235203
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“Asymmetric stark shifts in InGaAs/GaAs near-surface quantum wells: the image charge effect”. Chang K, Peeters FM, Journal of applied physics 88, 5246 (2000). http://doi.org/10.1063/1.1314905
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.068
Times cited: 20
DOI: 10.1063/1.1314905
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“Bright to dark exciton transition in symmetric coupled quantum wells”. Chang K, Peeters FM, Physical review : B : condensed matter and materials physics 63 (2001). http://doi.org/10.1103/PhysRevB.63.153307
Abstract: The energy dispersion of an exciton in a coupled quantum well is modified by an external in-plane magnetic field. We find that the in-plane magnetic field can shift the ground state of the magnetoexciton from a zero in-plane center-of-mass (CM) momentum to a finite CM momentum, and render the ground state of the magnetoexciton stable against radiative recombination due to momentum conservation. At the same time, a spatial separation of the electron and hole is realized. Thus an in-plane magnetic field can be used to tailor the radiative properties of excitons in coupled quantum wells.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 42
DOI: 10.1103/PhysRevB.63.153307
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“Spin-polarized ballistic transport in diluted magnetic semiconductor quantum wire systems”. Chang K, Peeters FM, Physical review : B : condensed matter and materials physics 68, 205320 (2003). http://doi.org/10.1103/PhysRevB.68.205320
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 23
DOI: 10.1103/PhysRevB.68.205320
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“Spin-polarized tunneling through diluted magnetic semiconductor barriers”. Chang K, Peeters FM, Solid state communications 120, 181 (2001). http://doi.org/10.1016/S0038-1098(01)00370-2
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.554
Times cited: 35
DOI: 10.1016/S0038-1098(01)00370-2
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“Magnetic field tuning of the effective g factor in a diluted magnetic semiconductor quantum dot”. Chang K, Xia JB, Peeters FM, Applied physics letters 82, 2661 (2003). http://doi.org/10.1063/1.1568825
Abstract: The spin interaction and the effective g factor of a magnetic exciton (ME) are investigated theoretically in a diluted magnetic semiconductor (DMS) quantum dot (QD), including the Coulomb interaction and the sp-d exchange interaction. At low magnetic field, the ME energy decreases rapidly with increasing magnetic field and saturates at high magnetic field for high Mn concentration. The ground state of the ME exhibits an interesting crossing behavior between sigma(+)-ME and sigma(-)-ME for low Mn concentration. The g(ex) factor of the ME in a DMS QD displays a monotonic decrease with increasing magnetic field and can be tuned to zero by an external magnetic field. (C) 2003 American Institute of Physics.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.411
Times cited: 56
DOI: 10.1063/1.1568825
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“Quantum-confined magneto-Stark effect in diluted magnetic semiconductor coupled quantum wells”. Chang K, Xia JB, Wu HB, Feng SL, Peeters FM, Applied physics letters 80, 1788 (2002). http://doi.org/10.1063/1.1459491
Abstract: The magneto-Stark effect in a diluted magnetic semiconductor (DMS) coupled quantum well (CQW) induced by an in-plane magnetic field is investigate theoretically. Unlike the usual electro-Stark effects, in a DMS CQW the Lorenz force leads to a spatially separated exciton. The in-plane magnetic field can shift the ground state of the magnetoexciton from a zero in-plane center of mass (CM)/momentum to a finite CM momentum, and render the ground state of magnetoexciton stable against radiative recombination due to momentum conservation. (C) 2002 American Institute of Physics.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.411
Times cited: 8
DOI: 10.1063/1.1459491
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“Gielis transformations for the audiovisual geometry database”. Chapman D, Gielis J, Symmetry : culture and science 32, 177 (2021). http://doi.org/10.26830/SYMMETRY_2021_2_177
Abstract: This publication introduces the audiovisual geometry database with Gielis transformations as initial records for a prototype of the database. A concise overview is given of the rationale behind the database and studying wave phenomena with Gielis transformations. First results on a form of timbral polyphony observed in Gielis curves and future work are briefly discussed.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.26830/SYMMETRY_2021_2_177
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“Orientation relationship of the austenite-to-ferrite transformation in austenitic stainless steels due to dissolution corrosion in contact with liquid Pb-Bi eutectic”. Charalampopoulou E, Cautaerts N, Van der Donck T, Schryvers D, Lambrinou K, Delville R, Scripta materialia 167, 66 (2019). http://doi.org/10.1016/J.SCRIPTAMAT.2019.03.035
Abstract: The orientation relationship of an austenite-to-ferrite phase transformation in 316L stainless steels induced by the loss of austenite stabilizers resulting from the steel dissolution corrosion in liquid Pb-Bi eutectic was studied by means of electron backscatter diffraction. The misorientations at the austenite/ferrite interface were compared to the prevailing orientation relationship models in steels. The Pitsch orientation relationship model was found to be predominant, which is unusual for austenite-to-ferrite bulk transformations in steels. The nature of this particular transformation, which involves loss of steel alloying elements and the presence of an interfacial liquid metal layer, is discussed to explain this finding. (C) 2019 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 3.747
Times cited: 3
DOI: 10.1016/J.SCRIPTAMAT.2019.03.035
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“Transmission electron microscopy study of complex oxide scales on DIN 1.4970 steel exposed to liquid Pb-Bi eutectic”. Charalampopoulou E, Delville R, Verwerft M, Lambrinou K, Schryvers D, Corrosion science 147, 22 (2019). http://doi.org/10.1016/j.corsci.2018.10.018
Abstract: The deployment of Gen-IV lead-cooled fast reactors requires a good compatibility between the selected structural/cladding steels and the inherently corrosive heavy liquid metal coolant. An effective liquid metal corrosion mitigation strategy involves the in-situ steel passivation in contact with the oxygen-containing Pb-alloy coolant. Transmission electron microscopy was used in this work to study the multi-layered oxide scales forming on an austenitic stainless steel fuel cladding exposed to oxygen-containing (CO ≈ 10−6 mass%) static liquid leadbismuth eutectic (LBE) for 1000 h between 400 and 500 °C. The oxide scale constituents were analyzed, including the intertwined phases comprising the innermost biphasic layer.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Times cited: 5
DOI: 10.1016/j.corsci.2018.10.018
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“Early stages of dissolution corrosion in 316L and DIN 1.4970 austenitic stainless steels with and without anticorrosion coatings in static liquid lead-bismuth eutectic (LBE) at 500 degrees C”. Charalampopoulou E, Lambrinou K, Van der Donck T, Paladino B, Di Fonzo F, Azina C, Eklund P, Mraz S, Schneider JM, Schryvers D, Delville R, Materials Characterization 178, 111234 (2021). http://doi.org/10.1016/J.MATCHAR.2021.111234
Abstract: This work addresses the early stages (<= 1000 h) of the dissolution corrosion behavior of 316L and DIN 1.4970 austenitic stainless steels in contact with oxygen-poor (C-O < 10(-8) mass%), static liquid lead-bismuth eutectic (LBE) at 500 degrees C for 600-1000 h. The objective of this study was to determine the relative early-stage resistance of the uncoated steels to dissolution corrosion and to assess the protectiveness of select candidate coatings (Cr2AlC, Al2O3, V2AlxCy). The simultaneous exposure of steels with intended differences in microstructure and thermomechanical state showed the effects of steel grain size, density of annealing/deformation twins, and secondary precipitates on the steel dissolution corrosion behavior. The findings of this study provide recommendations on steel manufacturing with the aim of using the steels to construct Gen-IV lead-cooled fast reactors.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 2.714
DOI: 10.1016/J.MATCHAR.2021.111234
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“Synthesis and cation distribution in the new bismuth oxyhalides with the Sillen-Aurivillius intergrowth structures”. Charkin DO, Akinfiev VS, Alekseeva AM, Batuk M, Abakumov AM, Kazakov SM, Journal of the Chemical Society : Dalton transactions 44, 20568 (2015). http://doi.org/10.1039/c5dt02620b
Abstract: About 20 new compounds with the Sillen-Aurivillius intergrowth structure, (MeMeBi3Nb2O11X)-Me-1-Bi-2 (Me-1 = Pb, Sr, Ba; Me-2 = Ca, Sr, Ba; X = Cl, Br, I), have been prepared. They are composed of stacking of [ANb(2)O(7)] perovskite blocks, fluorite-type [M2O2] blocks and halogen sheets. The cation distribution between the fluorite and perovskite layers has been studied for Ba2Bi3Nb2O11I, Ca1.25Sr0.75Bi3Nb2O11Cl, BaCaBi3Nb2O11Br and Sr2Bi3Nb2O11Cl. The smaller Me cations tend to reside in the perovskite block while the larger ones are situated in the fluorite-type block. The distribution of the elements was confirmed for BaCaBi3Nb2O11Br using energy dispersive X-ray analysis combined with scanning transmission electron microscopy (STEM-EDX). An electron diffraction study of this compound reveals a local symmetry lowering caused by weakly correlated rotation of NbO6 octahedra. Based on our findings, we suggest a new stability criterion for mixed-layer structures, which is that net charges of any two consecutive layers do not compensate for each other and only the whole layer sequence is electroneutral.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.029
Times cited: 5
DOI: 10.1039/c5dt02620b
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“Synthesis and structural characterization of a novel Sillén &ndash, Aurivillius bismuth oxyhalide, PbBi3VO7.5Cl, and its derivatives”. Charkin DO, Plokhikh IV, Kazakov SM, Kalmykov SN, Akinfiev VS, Gorbachev AV, Batuk M, Abakumov AM, Teterin YA, Maslakov KI, Teterin AY, Ivanov KE, Solid state sciences 75, 27 (2018). http://doi.org/10.1016/j.solidstatesciences.2017.11.006
Abstract: A new Sillen – Aurivillius family of layered bismuth oxyhalides has been designed and successfully constructed on the basis of PbBiO2X(X = halogen) synthetic perites and g-form of Bi2VO5.5 solid elec- trolyte. This demonstrates, for the first time, the ability of the latter to serve as a building block in construction of mixed-layer structures. The parent compound PbBi3VO7.5-dCl (d = 0.05) has been investigated by powder XRD, TEM, XPS methods and magnetic susceptibility measurements. An unexpected but important condition for the formation of the mixed-layer structure is partial (ca. 5%) reduction of VV into VIV which probably suppresses competitive formation of apatite-like Pb – Bi vanadates. This reduction also stabilizes the g polymorphic form of Bi2VO5.5 not only in the intergrowth structure, but in Bi2V1-xMxO5.5-y (M – Nb, Sb) solid solutions.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.811
Times cited: 1
DOI: 10.1016/j.solidstatesciences.2017.11.006
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“Determination of the silver sulphide cluster size distribution via computer simulations”. Charlier E, Gijbels R, Van Doorselaer M, De Keyzer R page 85 (2000).
Abstract: Addition of a labile sulphur donor to light sensitive silver halide microcrystals results in the formation of a distribution of silver sulphide clusters on the crystal surface. These silver sulphide clusters enhance the efficiency of image formation during the photographic process. Their activity towards the capturing of light photons, however, is very critical to their size (aggregation number) and concentration. By incorporating gold ions into silver sulphide clusters it was possible to monitor the size distribution by measuring the amount of gold reacted. From these experiments, no evidence was found for aggregation of the reacted sulphur entities on the surface. The uptake of gold ions at different sulphur concentrations could well be fitted with a simulated size distribution when a catalyzed deposition of sulphur was assumed, with a reactivity of the surface equal to 1.0 % for the microcrystals studied. From a simulation of the silver sulphide cluster size distribution a correlation could also be found between increasing aggregation numbers and the absorption at increasing wavelengths in diffuse reflectance spectroscopy.
Keywords: H1 Book chapter; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
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“Functioning of thiocyanate ions during sulphur and sulphur-plus-gold Sensitization”. Charlier E, Gijbels R, Van Doorselaer M, De Keyzer R, , 172 (2000)
Abstract: Not much about the effect of thiocyanate addition on the sulphur ripening is known, although it is used for many applications in photographic practice. Via a combination of tracer analysis and diffuse reflectance spectroscopy the effect of thiocyanate addition on the sulphur and sulphur-plus-gold ripening could be unveiled. When thiocyanate is added prior to the sulphur addition, it appears to rearrange the silver halide surface in such way that the sulphur deposition rate is enhanced, but the supply of interstitials is limited. Addition of thiocyanate after the sulphur reaction results in the formation of thiocyanate complexes with silver, from which a silver ion is more easily deposited in a surface cell of the silver sulphide clusters thus enhancing the sensitization rate. For sulphur-plus-gold sensitized emulsions it was observed that part of the gold ions could be removed out of the Ag2-xAuxS clusters by addition of thiocyanate ions and subsequent washing. Hence, it was concluded that two different types of gold ions are present in the silver sulphide clusters; 1. gold ions which are substitutional for silver (bound between sulphur and bromide ions) 2. gold ions which bridge two or three sulphur atoms. Incorporation of gold ions into silver sulphide clusters suppresses their optical absorption in diffuse reflectance spectroscopy. Since the optical absorption at 505 nm can completely be restored by addition of thiocyanate, it is assumed that the entity absorbing at this wavelength is a monomer of silver sulphide.
Keywords: P1 Proceeding; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
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“Unveiling the composition of sulphur sensitization specks by their interactions with TAI”. Charlier E, van Doorselaer M, Gijbels R, de Keyzer R, Geuens I, Journal Of Imaging Science And Technology 44, 235 (2000)
Abstract: A two-step process for the formation of sensitivity centers different from earlier described two-step processes was found for sulfur sensitized emulsions. After deposition of sulfur in the first step, it was found that the second step does not consist of rearrangement of sulfur over the surface, but of the supply of silver interstitial ions towards the deposited sulfur clusters. The two processes could be separated by adsorbing and desorbing TAI (4-hydroxy-1, 3,3a, 7-tetraazaindene) at/from the silver halide surface. When 1.5 mmol TAI/mol Ag is added before the sulfur reaction, the silver interstitials are immobilized but sulfur still can be deposited at the same level. By lowering the pH to 2.50 after this sulfur reaction, TAI is desorbed from the surface and the released interstitials then cause a restoration of the properties of a sulfur system without TAI. These effects could be demonstrated via diffuse reflectance spectroscopy (DRS), sensitometry and dielectric loss measurements. We could also confirm the isolation of silver sulfide clusters by TAI from other chemicals in the solution, by adsorption of TAI on the clusters.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 0.348
Times cited: 16
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“Bandgap engineering of two-dimensional semiconductor materials”. Chaves A, Azadani JG, Alsalman H, da Costa DR, Frisenda R, Chaves AJ, Song SH, Kim YD, He D, Zhou J, Castellanos-Gomez A, Peeters FM, Liu Z, Hinkle CL, Oh S-H, Ye PD, Koester SJ, Lee YH, Avouris P, Wang X, Low T, npj 2D Materials and Applications 4, 29 (2020). http://doi.org/10.1038/S41699-020-00162-4
Abstract: Semiconductors are the basis of many vital technologies such as electronics, computing, communications, optoelectronics, and sensing. Modern semiconductor technology can trace its origins to the invention of the point contact transistor in 1947. This demonstration paved the way for the development of discrete and integrated semiconductor devices and circuits that has helped to build a modern society where semiconductors are ubiquitous components of everyday life. A key property that determines the semiconductor electrical and optical properties is the bandgap. Beyond graphene, recently discovered two-dimensional (2D) materials possess semiconducting bandgaps ranging from the terahertz and mid-infrared in bilayer graphene and black phosphorus, visible in transition metal dichalcogenides, to the ultraviolet in hexagonal boron nitride. In particular, these 2D materials were demonstrated to exhibit highly tunable bandgaps, achieved via the control of layers number, heterostructuring, strain engineering, chemical doping, alloying, intercalation, substrate engineering, as well as an external electric field. We provide a review of the basic physical principles of these various techniques on the engineering of quasi-particle and optical bandgaps, their bandgap tunability, potentials and limitations in practical realization in future 2D device technologies.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Times cited: 329
DOI: 10.1038/S41699-020-00162-4
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“Topologically protected moiré, exciton at a twist-boundary in a van der Waals heterostructure”. Chaves A, Covaci L, Peeters FM, Milošević, MV, 2D materials 9, 025012 (2022). http://doi.org/10.1088/2053-1583/ac529d
Abstract: A twin boundary in one of the layers of a twisted van der Waals heterostructure separates regions with near opposite inter-layer twist angles. In a MoS<sub>2</sub>/WSe<sub>2</sub>bilayer, the regions with<inline-formula><tex-math><?CDATA $Rh^h$?></tex-math><math overflow=“scroll”><msubsup><mi>R</mi><mi>h</mi><mi>h</mi></msubsup></math><inline-graphic href=“tdmac529dieqn1.gif” type=“simple” /></inline-formula>and<inline-formula><tex-math><?CDATA $Rh^X$?></tex-math><math overflow=“scroll”><msubsup><mi>R</mi><mi>h</mi><mi>X</mi></msubsup></math><inline-graphic href=“tdmac529dieqn2.gif” type=“simple” /></inline-formula>stacking registry that defined the sub-lattices of the moiré honeycomb pattern would be mirror-reflected across such a twist boundary. In that case, we demonstrate that topologically protected chiral moiré exciton states are confined at the twist boundary. These are one-dimensional and uni-directional excitons with opposite velocities for excitons composed by electronic states with opposite valley/spin character, enabling intrinsic, guided, and far reaching valley-polarized exciton currents.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Impact Factor: 5.5
DOI: 10.1088/2053-1583/ac529d
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“Wave-packet dynamics and valley filter in strained graphene”. Chaves A, Covaci L, Rakhimov KY, Farias GA, Peeters FM, Physical review : B : condensed matter and materials physics 82, 205430 (2010). http://doi.org/10.1103/PhysRevB.82.205430
Abstract: The time evolution of a wave packet in strained graphene is studied within the tight-binding model and continuum model. The effect of an external magnetic field, as well as a strain-induced pseudomagnetic field, on the wave-packet trajectories and zitterbewegung are analyzed. Combining the effects of strain with those of an external magnetic field produces an effective magnetic field which is large in one of the Dirac cones, but can be practically zero in the other. We construct an efficient valley filter, where for a propagating incoming wave packet consisting of momenta around the K and K' Dirac points, the outgoing wave packet exhibits momenta in only one of these Dirac points while the components of the packet that belong to the other Dirac point are reflected due to the Lorentz force. We also found that the zitterbewegung is permanent in time in the presence of either external or strain-induced magnetic fields, but when both the external and strain-induced magnetic fields are present, the zitterbewegung is transient in one of the Dirac cones, whereas in the other cone the wave packet exhibits permanent spatial oscillations.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 95
DOI: 10.1103/PhysRevB.82.205430
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“The Split-operator technique for the study of spinorial wavepacket dynamics”. Chaves A, Farias GA, Peeters FM, Ferreira R, Communications in computational physics 17, 850 (2015). http://doi.org/10.4208/cicp.110914.281014a
Abstract: The split-operator technique for wave packet propagation in quantum systems is expanded here to the case of propagatingwave functions describing Schrodinger particles, namely, charge carriers in semiconductor nanostructures within the effective mass approximation, in the presence of Zeeman effect, as well as of Rashba and Dresselhaus spin-orbit interactions. We also demonstrate that simple modifications to the expanded technique allow us to calculate the time evolution of wave packets describing Dirac particles, which are relevant for the study of transport properties in graphene.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.004
Times cited: 24
DOI: 10.4208/cicp.110914.281014a
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“Wave packet dynamics in semiconductor quantum rings of finite width”. Chaves A, Farias GA, Peeters FM, Szafran B, Physical review : B : solid state 80, 125331 (2009). http://doi.org/10.1103/PhysRevB.80.125331
Abstract: The time evolution of a wave packet injected into a semiconductor quantum ring is investigated in order to obtain the transmission and reflection probabilities. Within the effective-mass approximation, the time-dependent Schrödinger equation is solved for a system with nonzero width of the ring and leads and finite potential-barrier heights, where we include smooth lead-ring connections. In the absence of a magnetic field, an analysis of the projection of the wave function over the different subband states shows that when the injected wave packet is within a single subband, the junction can scatter this wave packet into different subbands but remarkably at the second junction the wave packet is scattered back into the subband state of the incoming wave packet. If a magnetic field is applied perpendicularly to the ring plane, transmission and reflection probabilities exhibit Aharonov-Bohm (AB) oscillations and the outgoing electrons may end up in different subband states from those of the incoming electrons. Localized impurities, placed in the ring arms, influence the AB oscillation period and amplitude. For a single impurity or potential barrier of sufficiently strong strength, the period of the AB oscillations is halved while for two impurities localized in diametrically opposite points of the ring, the original AB period is recovered. A theoretical investigation of the confined states and time evolution of wave packets in T wires is also made, where a comparison between this system and the lead-ring junction is drawn.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 40
DOI: 10.1103/PhysRevB.80.125331
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“Conditions for nonmonotonic vortex interaction in two-band superconductors”. Chaves A, Komendová, L, Milošević, MV, Andrade JS, Farias GA, Peeters FM, Physical review : B : condensed matter and materials physics 83, 214523 (2011). http://doi.org/10.1103/PhysRevB.83.214523
Abstract: We describe a semianalytic approach to the two-band Ginzburg-Landau theory, which predicts the behavior of vortices in two-band superconductors. We show that the character of the short-range vortex-vortex interaction is determined by the sign of the normal domain-superconductor interface energy, in analogy with the conventional differentiation between type I and type II superconductors. However, we also show that the long-range interaction is determined by a modified Ginzburg-Landau parameter κ*, different from the standard κ of a bulk superconductor. This opens the possibility for nonmonotonic vortex-vortex interaction, which is temperature dependent, and can be further tuned by alterations of the material on the microscopic scale.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 46
DOI: 10.1103/PhysRevB.83.214523
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“Anisotropic exciton Stark shift in black phosphorus”. Chaves A, Low T, Avouris P, Çakir D, Peeters FM, Physical review : B : condensed matter and materials physics 91, 155311 (2015). http://doi.org/10.1103/PhysRevB.91.155311
Abstract: We calculate the excitonic spectrum of few-layer black phosphorus by direct diagonalization of the effective mass Hamiltonian in the presence of an applied in-plane electric field. The strong attractive interaction between electrons and holes in this system allows one to investigate the Stark effect up to very high ionizing fields, including also the excited states. Our results show that the band anisotropy in black phosphorus becomes evident in the direction-dependent field-induced polarizability of the exciton.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 88
DOI: 10.1103/PhysRevB.91.155311
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“Theoretical investigation of electron-hole complexes in anisotropic two-dimensional materials”. Chaves A, Mayers MZ, Peeters FM, Reichman DR, Physical review B 93, 115314 (2016). http://doi.org/10.1103/PhysRevB.93.115314
Abstract: Trions and biexcitons in anisotropic two-dimensional materials are investigated within an effective mass theory. Explicit results are obtained for phosphorene and arsenene, materials that share features such as a direct quasiparticle gap and anisotropic conduction and valence bands. Trions are predicted to have remarkably high binding energies and an elongated electron-hole structure with a preference for alignment along the armchair direction, where the effective masses are lower. We find that biexciton binding energies are also notably large, especially for monolayer phosphorene, where they are found to be twice as large as those for typical monolayer transition metal dichalcogenides.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 33
DOI: 10.1103/PhysRevB.93.115314
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“Tunable magnetic focusing using Andreev scattering in superconductor-graphene hybrid devices”. Chaves A, Moura VN, Linard FJA, Covaci L, Milošević, MV, Journal Of Applied Physics 128, 124303 (2020). http://doi.org/10.1063/5.0020392
Abstract: We perform the wavepacket dynamics simulation of a graphene-based device where propagating electron trajectories are tamed by an applied magnetic field toward a normal/superconductor interface. The magnetic field controls the incidence angle of the incoming electronic wavepacket at the interface, which results in the tunable electron-hole ratio in the reflected wave function due to the angular dependence of the Andreev reflection. Here, mapped control of the quasiparticle trajectories by the external magnetic field not only defines an experimental probe for fundamental studies of the Andreev reflection in graphene but also lays the foundation for further development of magnetic focusing devices based on nanoengineered superconducting two-dimensional materials.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Impact Factor: 3.2
Times cited: 1
DOI: 10.1063/5.0020392
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“Exotic state seen at high temperatures”. Chaves A, Neilson D, Nature 574, 39 (2019). http://doi.org/10.1038/D41586-019-02906-9
Abstract: The phenomenon of Bose-Einstein condensation is typically limited to extremely low temperatures. The effect has now been spotted at much higher temperatures for particles called excitons in atomically thin semiconductors.
Keywords: Editorial; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 40.137
Times cited: 2
DOI: 10.1038/D41586-019-02906-9
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“Tunable effective masses of magneto-excitons in two-dimensional materials”. Chaves A, Peeters FM, Solid State Communications 334, 114371 (2021). http://doi.org/10.1016/J.SSC.2021.114371
Abstract: Excitonic properties of Ge2H2 and Sn2H2, also known as Xanes, are investigated within the effective mass model. A perpendicularly applied magnetic field induces a negative shift on the exciton center-of-mass kinetic energy that is approximately quadratic with its momentum, thus pushing down the exciton dispersion curve and flattening it. This can be interpreted as an increase in the effective mass of the magneto-exciton, tunable by the field intensity. Our results show that in low effective mass two-dimensional semiconductors, such as Xanes, the applied magnetic field allows one to tune the magneto-exciton effective mass over a wide range of values.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.554
DOI: 10.1016/J.SSC.2021.114371
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“Vortex-vortex interaction in bulk superconductors : Ginzburg-Landau theory”. Chaves A, Peeters FM, Farias GA, Milošević, MV, Physical review : B : condensed matter and materials physics 83, 054516 (2011). http://doi.org/10.1103/PhysRevB.83.054516
Abstract: The vortex-vortex interaction potential in bulk superconductors is calculated within the Ginzburg-Landau (GL) theory and is obtained from a numerical solution of a set of two coupled nonlinear GL differential equations for the vector potential and the superconducting order parameter, where the merger of vortices into a giant vortex is allowed. Further, the interaction potentials between a vortex and a giant vortex and between a vortex and an antivortex are obtained for both type-I and type-II superconductors. Our numerical results agree asymptotically with the analytical expressions for large intervortex separations that are available in the literature. We propose empirical expressions valid over the full interaction range, which are fitted to our numerical data for different values of the GL parameter.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 31
DOI: 10.1103/PhysRevB.83.054516
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“Signatures of subband excitons in few-layer black phosphorus”. Chaves A, Sousa GO, Khaliji K, da Costa DR, Farias GA, Low T, Physical Review B 103, 165428 (2021). http://doi.org/10.1103/PHYSREVB.103.165428
Abstract: Recent experimental measurements of light absorption in few-layer black phosphorus (BP) revealed a series of high and sharp peaks, interspersed by pairs of lower and broader features. Here, we propose a theoretical model for these excitonic states in few-layer BP within a continuum approach for the in-plane degrees of freedom and a tight-binding approximation that accounts for interlayer couplings. This yields excitonic transitions between different combinations of the subbands created by the coupled BP layers, which leads to a series of high and low oscillator strength excitonic states, consistent with the experimentally observed bright and dark exciton peaks, respectively. The main characteristics of such subband exciton states, as well as the possibility to control their energies and oscillator strengths via applied electric and magnetic fields, are discussed, towards a full understanding of the excitonic spectrum of few-layer BP and its tunability.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
DOI: 10.1103/PHYSREVB.103.165428
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“Correlating structure and detection properties in HgTe nanocrystal films”. Chee S-S, Greboval C, Vale Magalhaes D, Ramade J, Chu A, Qu J, Rastogi P, Khalili A, Dang TH, Dabard C, Prado Y, Patriarche G, Chaste J, Rosticher M, Bals S, Delerue C, Lhuillier E, Nano Letters 21, 4145 (2021). http://doi.org/10.1021/ACS.NANOLETT.0C04346
Abstract: HgTe nanocrystals (NCs) enable broadly tunable infrared absorption, now commonly used to design light sensors. This material tends to grow under multipodic shapes and does not present well-defined size distributions. Such point generates traps and reduces the particle packing, leading to a reduced mobility. It is thus highly desirable to comprehensively explore the effect of the shape on their performance. Here, we show, using a combination of electron tomography and tight binding simulations, that the charge dissociation is strong within HgTe NCs, but poorly shape dependent. Then, we design a dual-gate field-effect-transistor made of tripod HgTe NCs and use it to generate a planar p-n junction, offering more tunability than its vertical geometry counterpart. Interestingly, the performance of the tripods is higher than sphere ones, and this can be correlated with a stronger Te excess in the case of sphere shapes which is responsible for a higher hole trap density.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 12.712
Times cited: 20
DOI: 10.1021/ACS.NANOLETT.0C04346
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