“Reversible ratchet effects in a narrow superconducting ring”. Jiang J, Wang Y-L, Milošević, MV, Xiao Z-L, Peeters FM, Chen Q-H, Physical Review B 103, 014502 (2021). http://doi.org/10.1103/PHYSREVB.103.014502
Abstract: We study the ratchet effect in a narrow pinning-free superconductive ring based on time-dependent Ginzburg-Landau (TDGL) equations. Voltage responses to external dc and ac currents at various magnetic fields are studied. Due to asymmetric barriers for flux penetration and flux exit in the ring-shaped superconductor, the critical current above which the flux-flow state is reached, as well as the critical current for the transition to the normal state, are different for the two directions of applied current. These effects cooperatively cause ratchet signal reversal at high magnetic fields, which has not been reported to date in a pinning-free system. The ratchet signal found here is larger than those induced by asymmetric pinning potentials. Our results also demonstrate the feasibility of using mesoscopic superconductors to employ a superconducting diode effect in versatile superconducting devices.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 4
DOI: 10.1103/PHYSREVB.103.014502
|
“Grain boundaries as a diffusion-limiting factor in lithium-rich NMC cathodes for high-energy lithium-ion batteries”. Abakumov AM, Li C, Boev A, Aksyonov DA, Savina AA, Abakumova TA, Van Tendeloo G, Bals S, ACS applied energy materials 4, 6777 (2021). http://doi.org/10.1021/ACSAEM.1C00872
Abstract: High-energy lithium-rich layered transition metal oxides are capable of delivering record electrochemical capacity and energy density as positive electrodes for Li-ion batteries. Their electrochemical behavior is extremely complex due to sophisticated interplay between crystal structure, electronic structure, and defect structure. Here we unravel an extra level of this complexity by revealing that the most typical representative Li1.2Ni0.13Mn0.54Co0.13O2 material, prepared by a conventional coprecipitation technique with Na2CO3 as a precipitating agent, contains abundant coherent (001) grain boundaries with a Na-enriched P2-structured block due to segregation of the residual sodium traces. The trigonal prismatic oxygen coordination of Na triggers multiple nanoscale twinning, giving rise to incoherent (104) boundaries. The cationic layers at the (001) grain boundaries are filled with transition metal cations being Mn-depleted and Co-enriched; this makes them virtually not permeable for the Li+ cations, and therefore they negatively influence the Li diffusion in and out of the spherical agglomerates. These results demonstrate that besides the mechanisms intrinsic to the crystal and electronic structure of Li-rich cathodes, their rate capability might also be depreciated by peculiar microstructural aspects. Dedicated engineering of grain boundaries opens a way for improving inherently sluggish kinetics of these materials.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Times cited: 4
DOI: 10.1021/ACSAEM.1C00872
|
“Optical versus electron diffraction imaging of Twist-angle in 2D transition metal dichalcogenide bilayers”. Psilodimitrakopoulos S, Orekhov A, Mouchliadis L, Jannis D, Maragkakis GM, Kourmoulakis G, Gauquelin N, Kioseoglou G, Verbeeck J, Stratakis E, npj 2D Materials and Applications 5, 77 (2021). http://doi.org/10.1038/S41699-021-00258-5
Abstract: Atomically thin two-dimensional (2D) materials can be vertically stacked with van der Waals bonds, which enable interlayer coupling. In the particular case of transition metal dichalcogenide (TMD) bilayers, the relative direction between the two monolayers, coined as twist-angle, modifies the crystal symmetry and creates a superlattice with exciting properties. Here, we demonstrate an all-optical method for pixel-by-pixel mapping of the twist-angle with a resolution of 0.55(degrees), via polarization-resolved second harmonic generation (P-SHG) microscopy and we compare it with four-dimensional scanning transmission electron microscopy (4D STEM). It is found that the twist-angle imaging of WS2 bilayers, using the P-SHG technique is in excellent agreement with that obtained using electron diffraction. The main advantages of the optical approach are that the characterization is performed on the same substrate that the device is created on and that it is three orders of magnitude faster than the 4D STEM. We envisage that the optical P-SHG imaging could become the gold standard for the quality examination of TMD superlattice-based devices.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Times cited: 4
DOI: 10.1038/S41699-021-00258-5
|
“Optimized 3D Reconstruction of Large, Compact Assemblies of Metallic Nanoparticles”. Altantzis T, Wang D, Kadu A, van Blaaderen A, Bals S, Journal Of Physical Chemistry C 125, 26240 (2021). http://doi.org/10.1021/acs.jpcc.1c08478
Abstract: 3D characterization of assemblies of nanoparticles is of great importance to determine their structure-property connection. Such investigations become increasingly more challenging when the assemblies become larger and more compact. In this paper, we propose an optimized approach for electron tomography to minimize artefacts related to beam broadening in High Angle Annular Dark-Field Scanning Transmission Electron Microscopy mode. These artefacts are typically present at one side of the reconstructed 3D data set for thick nanoparticle assemblies. To overcome this problem, we propose a procedure in which two tomographic tilt series of the same sample are acquired. After acquiring the first series, the sample is flipped over 180o, and a second tilt series is acquired. By merging the two reconstructions, blurring in the reconstructed volume is minimized. Next, this approach is combined with an advanced three-dimensional reconstruction algorithm yielding quantitative structural information. Here, the approach is applied to a thick and compact assembly of spherical Au nanoparticles, but the methodology can we used to investigate a broad range of samples.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Applied Electrochemistry & Catalysis (ELCAT)
Impact Factor: 4.536
Times cited: 4
DOI: 10.1021/acs.jpcc.1c08478
|
“Probing charge density wave phases and the Mott transition in 1T-TaS₂I by inelastic light scattering”. Mijin SD, Baum A, Bekaert J, Solajic A, Pesic J, Liu Y, He G, Milošević, MV, Petrovic C, Popovic Z V, Hackl R, Lazarevic N, Physical Review B 103, 245133 (2021). http://doi.org/10.1103/PHYSREVB.103.245133
Abstract: We present a polarization-resolved, high-resolution Raman scattering study of the three consecutive charge density wave (CDW) regimes in 1T-TaS2 single crystals, supported by ab initio calculations. Our analysis of the spectra within the low-temperature commensurate (C-CDW) regime shows P (3) over bar symmetry of the system, thus excluding the previously proposed triclinic stacking of the “star-of-David” structure, and promoting trigonal or hexagonal stacking instead. The spectra of the high-temperature incommensurate (IC-CDW) phase directly project the phonon density of states due to the breaking of the translational invariance, supplemented by sizable electron-phonon coupling. Between 200 and 352 K, our Raman spectra show contributions from both the IC-CDW and the C-CDW phases, indicating their coexistence in the so-called nearly commensurate (NC-CDW) phase. The temperature dependence of the symmetry-resolved Raman conductivity indicates the stepwise reduction of the density of states in the CDW phases, followed by a Mott transition within the C-CDW phase. We determine the size of the Mott gap to be Omega(gap) approximate to 170-190 meV, and track its temperature dependence.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 4
DOI: 10.1103/PHYSREVB.103.245133
|
“Strong anisotropic optical properties of 8-Pmmn borophene : a many-body perturbation study”. Nazar ND, Vazifehshenas T, Ebrahimi MR, Peeters FM, Physical Chemistry Chemical Physics 23, 16417 (2021). http://doi.org/10.1039/D1CP01910D
Abstract: Using first-principles many-body perturbation theory, we investigate the optical properties of 8-Pmmn borophene at two levels of approximations; the GW method considering only the electron-electron interaction and the GW in combination with the Bethe-Salpeter equation including electron-hole coupling. The band structure exhibits anisotropic Dirac cones with semimetallic character. The optical absorption spectra are obtained for different light polarizations and we predict strong optical absorbance anisotropy. The absorption peaks undergo a global redshift when the electron-hole interaction is taken into account due to the formation of bound excitons which have an anisotropic excitonic wave function.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 4.123
Times cited: 4
DOI: 10.1039/D1CP01910D
|
“Terahertz magneto-optical properties of graphene hydrodynamic electron liquid”. Man LF, Xu W, Xiao YM, Wen H, Ding L, Van Duppen B, Peeters FM, Physical Review B 104, 125420 (2021). http://doi.org/10.1103/PHYSREVB.104.125420
Abstract: The discovery of the hydrodynamic electron liquid (HEL) in graphene [D. Bandurin et al., Science 351, 1055 (2016) and J. Crossno et al., Science 351, 1058 (2016)] has marked the birth of the solid-state HEL which can be probed near room temperature in a table-top setup. Here we examine the terahertz (THz) magneto-optical (MO) properties of a graphene HEL. Considering the case where the magnetic length l(B) = root h/eB is comparable to the mean-free path l(ee) for electron-electron interaction in graphene, the MO conductivities are obtained by taking a momentum balance equation approach on the basis of the Boltzmann equation. We find that when l(B) similar to l(ee), the viscous effect in a HEL can weaken significantly the THz MO effects such as cyclotron resonance and Faraday rotation. The upper hybrid and cyclotron resonance magnetoplasmon modes omega(+/-) are also obtained through the RPA dielectric function. The magnetoplasmons of graphene HEL at large wave-vector regime are affected by the viscous effect, and results in red-shifts of the magnetoplasmon frequencies. We predict that the viscosity in graphene HEL can affect strongly the magneto-optical and magnetoplasmonic properties, which can be verified experimentally.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 4
DOI: 10.1103/PHYSREVB.104.125420
|
“High-temperature multigap superconductivity in two-dimensional metal borides”. Sevik C, Bekaert J, Petrov M, Milošević, MV, Physical review materials 6, 024803 (2022). http://doi.org/10.1103/PhysRevMaterials.6.024803
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.4
Times cited: 4
DOI: 10.1103/PhysRevMaterials.6.024803
|
“Reducing electron beam damage through alternative STEM scanning strategies, Part II: Attempt towards an empirical model describing the damage process”. Jannis D, Velazco A, Béché, A, Verbeeck J, Ultramicroscopy , 113568 (2022). http://doi.org/10.1016/j.ultramic.2022.113568
Abstract: In this second part of a series we attempt to construct an empirical model that can mimick all experimental observations made regarding the role of an alternative interleaved scan pattern in STEM imaging on the beam damage in a specific zeolite sample. We make use of a 2D diffusion model that describes the dissipation of the deposited beam energy in the sequence of probe positions that are visited during the scan pattern. The diffusion process allows for the concept of trying to ‘outrun’ the beam damage by carefully tuning the dwell time and distance between consecutively visited probe positions. We add a non linear function to include a threshold effect and evaluate the accumulated damage in each part of the image as a function of scan pattern details. Together, these ingredients are able to describe qualitatively all aspects of the experimental data and provide us with a model that could guide a further optimisation towards even lower beam damage without lowering the applied electron dose. We deliberately remain vague on what is diffusing here which avoids introducing too many sample specific details. This provides hope that the model can be applied also in sample classes that were not yet studied in such great detail by adjusting higher level parameters: a sample dependent diffusion constant and damage threshold.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 2.2
Times cited: 4
DOI: 10.1016/j.ultramic.2022.113568
|
“Anisotropic etching of CVD grown graphene for ammonia sensing”. Yagmurcukardes N, Bayram A, Aydin H, Yagmurcukardes M, Acikbas Y, Peeters FM, Celebi C, IEEE sensors journal 22, 3888 (2022). http://doi.org/10.1109/JSEN.2022.3146220
Abstract: Bare chemical vapor deposition (CVD) grown graphene (GRP) was anisotropically etched with various etching parameters. The morphological and structural characterizations were carried out by optical microscopy and the vibrational properties substrates were obtained by Raman spectroscopy. The ammonia adsorption and desorption behavior of graphene-based sensors were recorded via quartz crystal microbalance (QCM) measurements at room temperature. The etched samples for ambient NH3 exhibited nearly 35% improvement and showed high resistance to humidity molecules when compared to bare graphene. Besides exhibiting promising sensitivity to NH3 molecules, the etched graphene-based sensors were less affected by humidity. The experimental results were collaborated by Density Functional Theory (DFT) calculations and it was shown that while water molecules fragmented into H and O, NH3 interacts weakly with EGPR2 sample which reveals the enhanced sensing ability of EGPR2. Apparently, it would be more suitable to use EGRP2 in sensing applications due to its sensitivity to NH3 molecules, its stability, and its resistance to H2O molecules in humid ambient.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 4.3
Times cited: 4
DOI: 10.1109/JSEN.2022.3146220
|
“Axion insulator states in a topological insulator proximitized to magnetic insulators : a tight-binding characterization”. Shafiei M, Fazileh F, Peeters FM, Milošević, MV, Physical review materials 6, 074205 (2022). http://doi.org/10.1103/PHYSREVMATERIALS.6.074205
Abstract: The recent discovery of axion states in materials such as antiferromagnetic topological insulators has boosted investigations of the magnetoelectric response in topological insulators and their promise towards realizing dissipationless topological electronics. In this paper, we develop a tight-binding methodology to explore the emergence of axion states in Bi2Se3 in proximity to magnetic insulators on the top and bottom surfaces. The topological protection of the surface states is lifted by a time-reversal-breaking perturbation due to the proximity of a magnetic insulator, and a gap is opened on the surfaces, giving rise to half-quantized Hall conductance and a zero Hall plateau-evidencing an axion insulator state. We developed a real-space tight-binding Hamiltonian for Bi2Se3 using first-principles data. Transport properties of the system were obtained within the Landauer-Buttiker formalism, and we discuss the creation of axion states through Hall conductance and a zero Hall plateau at the surfaces, as a function of proximitized magnetization and corresponding potentials at the surfaces, as well as the thickness of the topological insulator.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.4
Times cited: 4
DOI: 10.1103/PHYSREVMATERIALS.6.074205
|
“Isolated and hybrid bilayer graphene quantum rings”. Mirzakhani M, da Costa DR, Peeters FM, Physical review B 105, 115430 (2022). http://doi.org/10.1103/PHYSREVB.105.115430
Abstract: Using the continuum model, we investigate the electronic properties of two types of bilayer graphene (BLG) quantum ring (QR) geometries: (i) An isolated BLG QR and (ii) a monolayer graphene (MLG) with a QR put on top of an infinite graphene sheet (hybrid BLG QR). Solving the Dirac-Weyl equation in the presence of a perpendicular magnetic field and applying the infinite mass boundary condition at the ring boundaries, we obtain analytical results for the energy levels and corresponding wave spinors for both structures. In the case of isolated BLG QR, we observe a sizable and magnetically tunable band gap which agrees with the tight-binding transport simulations. Our analytical results also show the intervalley symmetry EeK (m) = ???EK??? h (m) between the electron (e) and the hole (h) states (m is the angular momentum quantum number) for the energy spectrum of the isolated BLG QR. The presence of interface boundary in a hybrid BLG QR modifies drastically the energy levels as compared with that of an isolated BLG QR. Its energy levels are tunable from MLG dot to isolated BLG QR and to MLG Landau energy levels as the magnetic field is varied. Our predictions can be verified experimentally using different techniques such as by magnetotransport measurements.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.7
Times cited: 4
DOI: 10.1103/PHYSREVB.105.115430
|
“Self-assembled epitaxial cathode-electrolyte nanocomposites for 3D microbatteries”. Cunha DM, Gauquelin N, Xia R, Verbeeck J, Huijben M, ACS applied materials and interfaces 14, 42208 (2022). http://doi.org/10.1021/ACSAMI.2C09474
Abstract: The downscaling of electronic devices requires rechargeable microbatteries with enhanced energy and power densities. Here, we evaluate self-assembled vertically aligned nano-composite (VAN) thin films as a platform to create high-performance three-dimensional (3D) microelectrodes. This study focuses on controlling the VAN formation to enable interface engineering between the LiMn2O4 cathode and the (Li,La)TiO3 solid electrolyte. Electrochemical analysis in a half cell against lithium metal showed the absence of sharp redox peaks due to the confinement in the electrode pillars at the nanoscale. The (100)-oriented VAN thin films showed better rate capability and stability during extensive cycling due to the better alignment to the Li-diffusion channels. However, an enhanced pseudocapacitive contribution was observed for the increased total surface area within the (110)-oriented VAN thin films. These results demonstrate for the first time the electrochemical behavior of cathode-electrolyte VANs for lithium-ion 3D microbatteries while pointing out the importance of control over the vertical interfaces.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 9.5
Times cited: 4
DOI: 10.1021/ACSAMI.2C09474
|
“Two-dimensional semimetal states in transition metal trichlorides : a first-principles study”. Yu Y, Xie X, Liu X, Li J, Peeters FM, Li L, Applied physics letters 121, 112405 (2022). http://doi.org/10.1063/5.0105605
Abstract: The two-dimensional (2D) transition metal trihalide (TMX3, X = Cl, Br, I) family has attracted considerable attention in recent years due to the realization of CrCl3, CrBr3, and CrI3 monolayers. Up to now, the main focus of the theoretically predicted TMX3 monolayers has been on the Chern insulator states, which can realize the quantum anomalous Hall effect. Here, using first-principles calculations, we theoretically demonstrate that the stable OsCl3 monolayer has a ferromagnetic ground state and a spin-polarized Dirac point without spin-orbit coupling (SOC), which disappears in the band structure of a Janus OsBr1.5Cl1.5 monolayer. We find that OsCl3 exhibits in-plane magnetization when SOC is included. By manipulating the magnetization direction along the C-2 symmetry axis of the OsCl3 structure, a gapless half-Dirac semimetal state with SOC can be achieved, which is different from the gapped Chern insulator state. Both semimetal states of OsCl3 monolayer without and with SOC exhibit a linear half-Dirac point (twofold degenerate) with high Fermi velocities. The achievement of the 2D semimetal state with SOC is expected to be found in other TMX3 monolayers, and we confirm it in a TiCl3 monolayer. This provides a different perspective to study the band structure with SOC of the 2D TMX3 family.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 4
Times cited: 4
DOI: 10.1063/5.0105605
|
“Interfaceless exchange bias in CoFe₂O₄, nanocrystals”. Rivas-Murias B, Testa-Anta M, Skorikov AS, Comesana-Hermo M, Bals S, Salgueirino V, Nano letters 23, 1688 (2023). http://doi.org/10.1021/ACS.NANOLETT.2C04268
Abstract: Oxidized cobalt ferrite nanocrystals with a modified distribution of the magnetic cations in their spinel structure give place to an unusual exchange-coupled system with a double reversal of the magnetization, exchange bias, and increased coercivity, but without the presence of a clear physical interface that delimits two well-differentiated magnetic phases. More specifically, the partial oxidation of cobalt cations and the formation of Fe vacancies at the surface region entail the formation of a cobalt-rich mixed ferrite spinel, which is strongly pinned by the ferrimagnetic background from the cobalt ferrite lattice. This particular configuration of exchange-biased magnetic behavior, involving two different magnetic phases but without the occurrence of a crystallographically coherent interface, revolu-tionizes the established concept of exchange bias phenomenology.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 10.8
Times cited: 4
DOI: 10.1021/ACS.NANOLETT.2C04268
|
“Enabling hydrate-based methane storage under mild operating conditions by periodic mesoporous organosilica nanotubes”. Beckwee EJ, Watson G, Houlleberghs M, Arenas Esteban D, Bals S, Van Der Voort P, Breynaert E, Martens J, Baron GV, Denayer JFM, Heliyon 9, e17662 (2023). http://doi.org/10.1016/J.HELIYON.2023.E17662
Abstract: Biomethane is a renewable natural gas substitute produced from biogas. Storage of this sustainable energy vector in confined clathrate hydrates, encapsulated in the pores of a host material, is a highly promising avenue to improve storage capacity and energy efficiency. Herein, a new type of periodic mesoporous organosilica (PMO) nanotubes, referred to as hollow ring PMO (HR-PMO), capable of promoting methane clathrate hydrate formation under mild working conditions (273 K, 3.5 MPa) and at high water loading (5.1 g water/g HR-PMO) is reported. Gravimetric uptake measurements reveal a steep single-stepped isotherm and a noticeably high methane storage capacity (0.55 g methane/g HR-PMO; 0.11 g methane/g water at 3.5 MPa). The large working capacity throughout consecutive pressure-induced clathrate hydrate formationdissociation cycles demonstrates the material's excellent recyclability (97% preservation of capacity). Supported by ex situ cryo-electron tomography and x-ray diffraction, HR-PMO nanotubes are hypothesized to promote clathrate hydrate nucleation and growth by distribution and confinement of water in the mesopores of their outer wall, along the central channels of the nanotubes and on the external nanotube surface. These findings showcase the potential for application of organosilica materials with hierarchical and interconnected pore systems for pressure-based storage of biomethane in confined clathrate hydrates.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Times cited: 4
DOI: 10.1016/J.HELIYON.2023.E17662
|
“Ab initio study of shallow acceptors in bixbyite V2O3”. Sarmadian N, Saniz R, Partoens B, Lamoen D, Journal of applied physics 117, 015703 (2015). http://doi.org/10.1063/1.4905316
Abstract: We present the results of our study on p-type dopability of bixbyite V2O3 using the Heyd, Scuseria, and Ernzerhof hybrid functional (HSE06) within the density functional theory (DFT) formalism. We study vanadium and oxygen vacancies as intrinsic defects and substitutional Mg, Sc, and Y as extrinsic defects. We find that Mg substituting V acts as a shallow acceptor, and that oxygen vacancies are electrically neutral. Hence, we predict Mg-doped V2O3 to be a p-type conductor. Our results also show that vanadium vacancies are relatively shallow, with a binding energy of 0.14 eV, so that they might also lead to p-type conductivity.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Impact Factor: 2.068
Times cited: 3
DOI: 10.1063/1.4905316
|
“Aerosol synthesis and characterization of ultrafine fullerene particles”. van Cleempoel A, Joutsensaari J, Kauppinen E, Gijbels R, Claeys M, Fullerene science and technology 6, 599 (1998). http://doi.org/10.1080/10641229809350223
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Times cited: 3
DOI: 10.1080/10641229809350223
|
“ALN nanoparticles XANES analysis: local atomic and electronic structure”. Soldatov A, Yalovega G, Smolentsev G, Kravtsova A, Lamoen D, Balasubramanian C, Marcelli A, Cinque G, Bellucci S, Nuclear Instruments &, Methods In Physics Research Section A-Accelerators Spectrometers Detectors And Associated Equipment 575, 85 (2007). http://doi.org/10.1016/j.nima.2007.01.031
Keywords: A1 Journal article; Electron Microscopy for Materials Science (EMAT);
Impact Factor: 1.362
Times cited: 3
DOI: 10.1016/j.nima.2007.01.031
|
“Ballistic current in metal-oxide-semiconductor field-effect transistors: the role of device topology”. Pourghaderi MA, Magnus W, Sorée B, Meuris M, de Meyer K, Heyns M, Journal of applied physics 106, 053702 (2009). http://doi.org/10.1063/1.3197635
Abstract: In this study we investigate the effect of device topology on the ballistic current in n-channel metal-oxide-semiconductor field-effect transistors. Comparison of the nanoscale planar and double-gate devices reveals that, down to a certain thickness of the double gate film, the ballistic current flowing in the double gate device is twice as large compared to its planar counterpart. On the other hand, further thinning of the film beyond this threshold is found to change noticeably the confinement and transport characteristics, which are strongly depending on the film material and the surface orientation. For double gate Ge and Si devices there exists a critical film thickness below which the transverse gate field is no longer effectively screened by the inversion layer electron gas and mutual inversion of the two gates is turned on. In the case of GaAs and other similar IIIV compounds, a decrease in the film thickness may drastically change the occupation of the L-valleys and therefore amend the transport properties. The simulation results show that, in both cases, the ballistic current and the transconductance are considerably enhanced.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.068
Times cited: 3
DOI: 10.1063/1.3197635
|
“Bilayer graphene Hall bar with a pn-junction”. Milovanovic SP, Masir MR, Peeters FM, Journal of applied physics 114, 113706 (2013). http://doi.org/10.1063/1.4821264
Abstract: We investigate the magnetic field dependence of the Hall and the bend resistances for a ballistic Hall bar structure containing a pn-junction sculptured from a bilayer of graphene. The electric response is obtained using the billiard model, and we investigate the cases of bilayer graphene with and without a band gap. Two different conduction regimes are possible: (i) both sides of the junction have the same carrier type and (ii) one side of the junction is n-type while the other one is p-type. The first case shows Hall plateau-like features in the Hall resistance that fade away as the band gap opens. The second case exhibits a bend resistance that is asymmetric in magnetic field as a consequence of snake states along the pn-interface, where the maximum is shifted away from zero magnetic field.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.068
Times cited: 3
DOI: 10.1063/1.4821264
|
“Cationic clathrate of type-III Ge172-xPxTey (y\approx21,5, x\approx2y) : synthesis, crystal structure and thermoelectric properties”. Kirsanova MA, Mori T, Maruyama S, Abakumov AM, Van Tendeloo G, Olenev A, Shevelkov AV, Inorganic chemistry 52, 8272 (2013). http://doi.org/10.1021/ic401203r
Abstract: A first germanium-based cationic clathrate of type-III, Ge129.3P42.7Te21.53, was synthesized and structurally characterized (space group P42/mnm, a = 19.948(3) Å, c = 10.440(2) Å, Z = 1). In its crystal structure, germanium and phosphorus atoms form three types of polyhedral cages centered with Te atoms. The polyhedra share pentagonal and hexagonal faces to form a 3D framework. Despite the complexity of the crystal structure, the Ge129.3P42.7Te21.53 composition corresponds to the Zintl counting scheme with a good accuracy. Ge129.3P42.7Te21.53 demonstrates semiconducting/insulating behavior of electric resistivity, high positive Seebeck coefficient (500 μV K1 at 300 K), and low thermal conductivity (<0.92 W m1 K1) within the measured temperature range.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 3
DOI: 10.1021/ic401203r
|
“Chemical and structural characterization of oxygen precipitates in silicon by infrared spectroscopy and TEM”. de Gryse O, Clauws P, Lebedev O, van Landuyt J, Vanhellemont J, Claeys C, Simoen E, Physica: B : condensed matter
T2 –, 21st International Conference on Defects in Semiconductors, JUL 16-20, 2001, GIESSEN, GERMANY 308, 294 (2001). http://doi.org/10.1016/S0921-4526(01)00801-8
Abstract: Infrared absorption spectra of polyhedral and platelet oxygen precipitates are analyzed using a modified Day-Thorpe approach (J. Phys.: Condens. Matter 11 (1999) 2551). The aspect ratio has been determined by TEM measurements. The reduced spectral function and the stoichiometry are extracted from the absorption spectra and the concentration of precipitated interstitial oxygen. One set of spectra reveal a Frohlich frequency around 1100 cm(-1) and another around 1110-1120 cm(-1). It is shown that the shift in the Frohlich frequency is not due to a different stoichiometry, but due to the detailed structure in the reduced spectral function. The oxygen precipitates consist of SiO. with gammaapproximate to1.1-1.2+/-0.1. (C) 2001 Elsevier Science B.V. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.386
Times cited: 3
DOI: 10.1016/S0921-4526(01)00801-8
|
“Correlation of microstructure and magnetotransport properties of epitaxially grown La-Ca-Mn-O3 thin films”. Habermeier HU, Razavi F, Lebedev O, Gross GM, Praus R, Zhang PX, Physica status solidi: B: basic research
T2 –, International Conference on Solid State Spectroscopy –, (ICSSS), SEP 05-07, 1999, SCHWABISCH-GMUND, GERMANY 215, 679 (1999). http://doi.org/10.1002/(SICI)1521-3951(199909)215:1<679::AID-PSSB679>3.0.CO;2-H
Abstract: We have investigated epitaxially grown single-crystalline Ca-doped LaMnO3 thin films using the pulsed laser deposition technique in a case study aimed to explore the possibilities buried in epitaxial stress tailoring in order to control the transport properties of CMR materials beyond the limits set by equilibrium thermodynamics. Depending on the film thickness there is an abrupt transition from pseudomorphic to epitaxial granular growth observable which is related to the epitaxial strain of the films. This is associated with microscopic stress relaxation and leads to well controllable modifications of the atomic arrangements of the Mn-O sublattice in the films. Due to the interrelation of double exchange, spin-, charge- and orbital ordering and the Jahn-Teller effect mediated coupling of the electronic system to the crystal lattice, the magnetotransport properties of the firms can be modified in a controllable way.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.674
Times cited: 3
DOI: 10.1002/(SICI)1521-3951(199909)215:1<679::AID-PSSB679>3.0.CO;2-H
|
“Crystal structure and magnetic properties of complex oxides Mg4-xNixO9, 0\leq x\leq4”. Tarakina NV, Nikulina EA, Hadermann J, Kellerman DG, Tyutunnik AP, Berger IF, Zubkov VG, Van Tendeloo G, Journal of solid state chemistry 180, 3180 (2007). http://doi.org/10.1016/j.jssc.2007.09.007
Abstract: In the Mg4−xNixNb2O9 (0x4) system two ranges of solid solution have been found. One of the solid solutions has a corundum-related structure type (space group ); the second one adopts the II-Ni4Nb2O9 structure type (space group Pbcn). The unit cell constants and atomic positions have been determined and refined using neutron powder diffraction data. Electron diffraction and high-resolution transmission electron microscopy (HRTEM) from MgNi3Nb2O9 crystals identify the presence of planar defects and the intergrowth of several (structurally related) phases. The magnetic susceptibility of Mg3NiNb2O9, measured in the temperature range T=2300 K, shows no indications of magnetic ordering at low temperatures, while for MgNi3Nb2O9 there is a magnetic ordering at temperatures below 45.5 K.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.299
Times cited: 3
DOI: 10.1016/j.jssc.2007.09.007
|
“Crystal structure and magnetic properties of the Cr-doped spiral antiferromagnet BiMnFe2O6”. Batuk D, de Dobbelaere C, Tsirlin AA, Abakumov AM, Hardy A, van Bael MK, Greenblatt M, Hadermann J, Materials research bulletin 48, 2993 (2013). http://doi.org/10.1016/j.materresbull.2013.04.038
Abstract: We report the Cr3+ for Mn3+ substitution in the BiMnFe2O6 structure. The BiCrxMn1-xFe2O6 solid solution is obtained by the solution-gel synthesis technique for the x values up to 0.3. The crystal structure investigation using a combination of X-ray powder diffraction and transmission electron microscopy demonstrates that the compounds retain the parent BiMnFe2O6 structure (for x = 0.3, a = 5.02010(6)angstrom, b = 7.06594(7)angstrom, c = 12.6174(1)angstrom, S.G. Pbcm, R-1 = 0.036, R-p = 0.011) with only a slight decrease in the cell parameters associated with the Cr3+ for Mn3+ substitution. Magnetic susceptibility measurements suggest strong similarities in the magnetic behavior of BiCrxMn1-xFe2O6 (x = 0.2; 0.3) and parent BiMnFe2O6. Only T-N slightly decreases upon Cr doping that indicates a very subtle influence of Cr3+ cations on the magnetic properties at the available substitution rates. (C) 2013 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.446
Times cited: 3
DOI: 10.1016/j.materresbull.2013.04.038
|
“Densification of thin a-C: H films grown from low-kinetic energy hydrocarbon radicals under the influence of H and C particle fluxes: a molecular dynamics study”. Neyts E, Bogaerts A, van de Sanden MCM, Journal of physics: D: applied physics 39, 1948 (2006). http://doi.org/10.1088/0022-3727/39/9/034
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.588
Times cited: 3
DOI: 10.1088/0022-3727/39/9/034
|
“Determination of ultimate leakage through rutile TiO2 and tetragonal ZrO2 from ab initio complex band calculations”. Clima S, Kaczer B, Govoreanu B, Popovici M, Swerts J, Verhulst AS, Jurczak M, De Gendt S, Pourtois G, IEEE electron device letters 34, 402 (2013). http://doi.org/10.1109/LED.2013.2238885
Abstract: First-principle complex band structures have been computed for rutile TiO2 and tetragonal ZrO2 insulating materials that are of current technological relevance to dynamic random accessmemorymetal-insulator-metal (MIM) capacitors. From the magnitude of the complex wave vectors in different orientations, the most penetrating orientations have been identified. Tunneling effective masses m(tunnel) have been extracted, are shown to be a crucial parameter for the intrinsic leakage, and are identified to be an important parameter in further scaling of MIM capacitors.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.048
Times cited: 3
DOI: 10.1109/LED.2013.2238885
|
“Effect of neutron irradiation on the characteristics of laser-produced plasma”. Khaydarov RT, Beisinbaeva HB, Sabitov NM, Terentev VB, Berdiyorov GR, Nuclear fusion 50, 025024 (2010). http://doi.org/10.1088/0029-5515/50/2/025024
Abstract: Using the mass-spectrometric method we studied the formation of multi-charged plasma ions during the interaction of laser radiation with solid targets irradiated by neutron beams. We found that structural defects, caused by the neutron irradiation, influence not only the efficiency of the process of material evaporation and emission of plasma, but also the ionization and recombination processes taking place at the initial stage of plasma formation and expansion. We also show the effect of the dose of neutron irradiation on the threshold of plasma formation from the surface of the target.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.307
Times cited: 3
DOI: 10.1088/0029-5515/50/2/025024
|
“The effect of the dielectric mismatch on excitons and trions in freestanding nanowires”. Slachmuylders AF, Partoens B, Magnus W, Peeters FM, Physica. E: Low-dimensional systems and nanostructures 40, 2166 (2008). http://doi.org/10.1016/j.physe.2007.10.091
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.221
Times cited: 3
DOI: 10.1016/j.physe.2007.10.091
|