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Author Vanherck, J.; Sorée, B.; Magnus, W.
Title Anisotropic bulk and planar Heisenberg ferromagnets in uniform, arbitrarily oriented magnetic fields Type A1 Journal article
Year 2018 Publication Journal of physics : condensed matter Abbreviated Journal J Phys-Condens Mat
Volume 30 Issue 27 Pages 275801
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract (down) Today, further downscaling of mobile electronic devices poses serious problems, such as energy consumption and local heat dissipation. In this context, spin wave majority gates made of very thin ferromagnetic films may offer a viable alternative. However, similar downscaling of magnetic thin films eventually enforces the latter to operate as quasi-2D magnets, the magnetic properties of which are not yet fully understood, especially those related to anisotropies and external magnetic fields in arbitrary directions. To this end, we have investigated the behaviour of an easy-plane and easy-axis anisotropic ferromagnet-both in two and three dimensions-subjected to a uniform magnetic field, applied along an arbitrary direction. In this paper, a spin-1/2 Heisenberg Hamiltonian with anisotropic exchange interactions is solved using double-time temperature-dependent Green's functions and the Tyablikov decoupling approximation. We determine various magnetic properties such as the Curie temperature and the magnetization as a function of temperature and the applied magnetic field, discussing the impact of the system's dimensionality and the type of anisotropy. The magnetic reorientation transition taking place in anisotropic Heisenberg ferromagnets is studied in detail. Importantly, spontaneous magnetization is found to be absent for easy-plane 2D spin systems with short range interactions.
Address
Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos 000434980600001 Publication Date 2018-05-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0953-8984 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.649 Times cited Open Access
Notes ; ; Approved Most recent IF: 2.649
Call Number UA @ lucian @ c:irua:151945UA @ admin @ c:irua:151945 Serial 5012
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Author Bizindavyi, J.; Verhulst, A.S.; Sorée, B.; Groeseneken, G.
Title Signature of ballistic band-tail tunneling current in tunnel FET Type A1 Journal article
Year 2020 Publication Ieee Transactions On Electron Devices Abbreviated Journal Ieee T Electron Dev
Volume 67 Issue 8 Pages 3486-3491
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract (down) To improve the interpretation of the tunnel field-effect transistor (TFET) measurements, we theoretically identify the signatures of the ballistic band-tail (BT) tunneling (BTT) current in the transfer and output characteristics of the TFETs. In particular, we demonstrate that the temperature dependence of a BTT-dominated subthreshold swing (SS) is in agreement with the reported experimental results. We explain how the temperature dependence of the output characteristics can be used to distinguish between a current dominated by BTT and a current dominated by trap-assisted tunneling. Finally, we propose an expression that relates the energetic extension of the quasi-extended BT states in the bandgap to the onset voltage for tunneling.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000552976100072 Publication Date 2020-07-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0018-9383 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.1 Times cited Open Access
Notes ; This work was supported by imec's Industrial Affiliation Program. ; Approved Most recent IF: 3.1; 2020 IF: 2.605
Call Number UA @ admin @ c:irua:171189 Serial 6601
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Author Tiwari, S.; Van de Put, M.L.; Temst, K.; Vandenberghe, W.G.; Sorée, B.
Title Atomistic modeling of spin and electron dynamics in two-dimensional magnets switched by two-dimensional topological insulators Type A1 Journal article
Year 2023 Publication Physical review applied Abbreviated Journal
Volume 19 Issue 1 Pages 014040-14049
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract (down) To design fast memory devices, we need material combinations that can facilitate fast read and write operations. We present a heterostructure comprising a two-dimensional (2D) magnet and a 2D topological insulator (TI) as a viable option for designing fast memory devices. We theoretically model the spin-charge dynamics between 2D magnets and 2D TIs. Using the adiabatic approximation, we combine the nonequi-librium Green's function method for spin-dependent electron transport and a time-quantified Monte Carlo method for simulating magnetization dynamics. We show that it is possible to switch a magnetic domain of a ferromagnet using the spin torque from spin-polarized edge states of a 2D TI. We show further that the switching of 2D magnets by TIs is strongly dependent on the interface exchange (Jint), and an opti-mal interface exchange, is required for efficient switching. Finally, we compare experimentally grown Cr compounds and show that Cr compounds with higher anisotropy (such as CrI3) result in a lower switching speed but a more stable magnetic order.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000920227500002 Publication Date 2023-01-12
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2331-7019 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.6 Times cited Open Access Not_Open_Access
Notes Approved Most recent IF: 4.6; 2023 IF: 4.808
Call Number UA @ admin @ c:irua:194312 Serial 7283
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Author Osca, J.; Moors, K.; Sorée, B.; Serra, L.
Title Fabry-Perot interferometry with gate-tunable 3D topological insulator nanowires Type A1 Journal article
Year 2021 Publication Nanotechnology Abbreviated Journal Nanotechnology
Volume 32 Issue 43 Pages 435002
Keywords A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Abstract (down) Three-dimensional topological insulator (3D TI) nanowires display remarkable magnetotransport properties that can be attributed to their spin-momentum-locked surface states such as quasiballistic transport and Aharonov-Bohm oscillations. Here, we focus on the transport properties of a 3D TI nanowire with a gated section that forms an electronic Fabry-Perot (FP) interferometer that can be tuned to act as a surface-state filter or energy barrier. By tuning the carrier density and length of the gated section of the wire, the interference pattern can be controlled and the nanowire can become fully transparent for certain topological surface-state input modes while completely filtering out others. We also consider the interplay of FP interference with an external magnetic field, with which Klein tunneling can be induced, and transverse asymmetry of the gated section, e.g. due to a top-gated structure, which displays an interesting analogy with Rashba nanowires. Due to its rich conductance phenomenology, we propose a 3D TI nanowire with gated section as an ideal setup for a detailed transport-based characterization of 3D TI nanowire surface states near the Dirac point, which could be useful towards realizing 3D TI nanowire-based topological superconductivity and Majorana bound states.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000682173800001 Publication Date 2021-07-20
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0957-4484 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.44 Times cited Open Access Not_Open_Access
Notes Approved Most recent IF: 3.44
Call Number UA @ admin @ c:irua:180487 Serial 6990
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Author Beckers, A.; Thewissen, M.; Sorée, B.
Title Energy filtering in silicon nanowires and nanosheets using a geometric superlattice and its use for steep-slope transistors Type A1 Journal article
Year 2018 Publication Journal of applied physics Abbreviated Journal J Appl Phys
Volume 124 Issue 14 Pages 144304
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract (down) This paper investigates energy filtering in silicon nanowires and nanosheets by resonant electron tunneling through a geometric superlattice. A geometric superlattice is any kind of periodic geometric feature along the transport direction of the nanowire or nanosheet. Multivalley quantum-transport simulations are used to demonstrate the manifestation of minibands and minibandgaps in the transmission spectra of such a superlattice. We find that the presence of different valleys in the conduction band of silicon favors a nanowire with a rectangular cross section for effective energy filtering. The obtained energy filter can consequently be used in the source extension of a field-effect transistor to prevent high-energy electrons from contributing to the leakage current. Self-consistent Schrodinger-Poisson simulations in the ballistic limit show minimum subthreshold swings of 6 mV/decade for geometric superlattices with indentations. The obtained theoretical performance metrics for the simulated devices are compared with conventional III-V superlatticeFETs and TunnelFETs. The adaptation of the quantum transmitting boundary method to the finite-element simulation of 3-D structures with anisotropic effective mass is presented in Appendixes A and B. Our results bare relevance in the search for steep-slope transistor alternatives which are compatible with the silicon industry and can overcome the power-consumption bottleneck inherent to standard CMOS technologies. Published by AIP Publishing.
Address
Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000447148100011 Publication Date 2018-10-11
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-8979; 1089-7550 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.068 Times cited 3 Open Access
Notes ; ; Approved Most recent IF: 2.068
Call Number UA @ lucian @ c:irua:154729UA @ admin @ c:irua:154729 Serial 5099
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Author Carrillo-Nunez, H.; Magnus, W.; Vandenberghe, W.G.; Sorée, B.; Peeters, F.M.
Title Phonon-assisted Zener tunneling in a p-n diode silicon nanowire Type A1 Journal article
Year 2013 Publication Solid state electronics Abbreviated Journal Solid State Electron
Volume 79 Issue Pages 196-200
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract (down) The Zener tunneling current flowing through a biased, abrupt p-n junction embedded in a cylindrical silicon nanowire is calculated. As the band gap becomes indirect for sufficiently thick wires, Zener tunneling and its related transitions between the valence and conduction bands are mediated by short-wavelength phonons interacting with mobile electrons. Therefore, not only the high electric field governing the electrons in the space-charge region but also the transverse acoustic (TA) and transverse optical (TO) phonons have to be incorporated in the expression for the tunneling current. The latter is also affected by carrier confinement in the radial direction and therefore we have solved the Schrodinger and Poisson equations self-consistently within the effective mass approximation for both conduction and valence band electrons. We predict that the tunneling current exhibits a pronounced dependence on the wire radius, particularly in the high-bias regime. (C) 2012 Elsevier Ltd. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Oxford Editor
Language Wos 000313611000037 Publication Date 2012-09-29
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0038-1101; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.58 Times cited 2 Open Access
Notes ; This work is supported by the Flemish Science Foundation (FWO-VI), and the Interuniversity Attraction Poles, Belgium State, Belgium Science Policy, and IMEC. One of the authors (W. Vandenberghe) gratefully acknowledges the support of a Ph.D. stipend from the Institute for the Promotion of Innovation through Science and Technology in Flanders (IWT-Vlaanderen). ; Approved Most recent IF: 1.58; 2013 IF: 1.514
Call Number UA @ lucian @ c:irua:110104 Serial 2600
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Author Van de Put, M.L.; Sorée, B.; Magnus, W.
Title Efficient solution of the Wigner-Liouville equation using a spectral decomposition of the force field Type A1 Journal article
Year 2017 Publication Journal of computational physics Abbreviated Journal J Comput Phys
Volume 350 Issue Pages 314-325
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract (down) The Wigner-Liouville equation is reformulated using a spectral decomposition of the classical force field instead of the potential energy. The latter is shown to simplify the Wigner-Liouville kernel both conceptually and numerically as the spectral force Wigner-Liouville equation avoids the numerical evaluation of the highly oscillatory Wigner kernel which is nonlocal in both position and momentum. The quantum mechanical evolution is instead governed by a term local in space and non-local in momentum, where the non locality in momentum has only a limited range. An interpretation of the time evolution in terms of two processes is presented; a classical evolution under the influence of the averaged driving field, and a probability-preserving quantum-mechanical generation and annihilation term. Using the inherent stability and reduced complexity, a direct deterministic numerical implementation using Chebyshev and Fourier pseudo-spectral methods is detailed. For the purpose of illustration, we present results for the time evolution of a one-dimensional resonant tunneling diode driven out of equilibrium. (C) 2017 Elsevier Inc. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication New York Editor
Language Wos 000413379000016 Publication Date 2017-09-02
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-9991 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.744 Times cited 5 Open Access
Notes ; ; Approved Most recent IF: 2.744
Call Number UA @ lucian @ c:irua:146630 Serial 4780
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Author Carrillo-Nuñez, H.; Magnus, W.; Vandenberghe, W.G.; Sorée, B.; Peeters, F.M.
Title Phonon-assisted Zener tunneling in a cylindrical nanowire transistor Type A1 Journal article
Year 2013 Publication Journal of applied physics Abbreviated Journal J Appl Phys
Volume 113 Issue 18 Pages 184507-184508
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract (down) The tunneling current has been computed for a cylindrical nanowire tunneling field-effect transistor (TFET) with an all-round gate that covers the source region. Being the underlying mechanism, band-to-band tunneling, mediated by electron-phonon interaction, is pronouncedly affected by carrier confinement in the radial direction and, therefore, involves the self-consistent solution of the Schrodinger and Poisson equations. The latter has been accomplished by exploiting a non-linear variational principle within the framework of the modified local density approximation taking into account the nonparabolicity of both the valence band and conduction band in relatively thick wires. Moreover, while the effective-mass approximation might still provide a reasonable description of the conduction band in relatively thick wires, we have found that the nonparabolicity of the valence band needs to be included. As a major conclusion, it is observed that confinement effects in nanowire tunneling field-effect transistors have a stronger impact on the onset voltage of the tunneling current in comparison with planar TFETs. On the other hand, the value of the onset voltage is found to be overestimated when the valence band nonparabolicity is ignored. (C) 2013 AIP Publishing LLC.
Address
Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000319294100093 Publication Date 2013-05-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-8979; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.068 Times cited 4 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-VI), and the Interuniversity Attraction Poles, Belgium State, Belgium Science Policy, and IMEC. ; Approved Most recent IF: 2.068; 2013 IF: 2.185
Call Number UA @ lucian @ c:irua:109651 Serial 2599
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Author Van de Put, M.L.; Vandenberghe, W.G.; Magnus, W.; Sorée, B.; Fischetti, M.V.
Title Modeling of inter-ribbon tunneling in graphene Type P1 Proceeding
Year 2015 Publication 18th International Workshop On Computational Electronics (iwce 2015) Abbreviated Journal
Volume Issue Pages
Keywords P1 Proceeding; Condensed Matter Theory (CMT)
Abstract (down) The tunneling current between two crossed graphene ribbons is described invoking the empirical pseudopotential approximation and the Bardeen transfer Hamiltonian method. Results indicate that the density of states is the most important factor determining the tunneling current between small (similar to nm) ribbons. The quasi-one dimensional nature of graphene nanoribbons is shown to result in resonant tunneling.
Address
Corporate Author Thesis
Publisher Ieee Place of Publication New york Editor
Language Wos Publication Date
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 978-0-692-51523-5 ISBN Additional Links UA library record; WoS full record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:134997 Serial 4206
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Author Mohammed, M.; Verhulst, A.S.; Verreck, D.; Van de Put, M.; Simoen, E.; Sorée, B.; Kaczer, B.; Degraeve, R.; Mocuta, A.; Collaert, N.; Thean, A.; Groeseneken, G.
Title Electric-field induced quantum broadening of the characteristic energy level of traps in semiconductors and oxides Type A1 Journal article
Year 2016 Publication Journal of applied physics Abbreviated Journal J Appl Phys
Volume 120 Issue 120 Pages 245704
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract (down) The trap-assisted tunneling (TAT) current in tunnel field-effect transistors (TFETs) is one of the crucial factors degrading the sub-60 mV/dec sub-threshold swing. To correctly predict the TAT currents, an accurate description of the trap is required. Since electric fields in TFETs typically reach beyond 10(6) V/cm, there is a need to quantify the impact of such high field on the traps. We use a quantum mechanical implementation based on the modified transfer matrix method to obtain the trap energy level. We present the qualitative impact of electric field on different trap configurations, locations, and host materials, including both semiconductors and oxides. We determine that there is an electric-field related trap level shift and level broadening. We find that these electric-field induced quantum effects can enhance the trap emission rates. Published by AIP Publishing.
Address
Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000392174000028 Publication Date 2016-12-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-8979; 1089-7550 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.068 Times cited 6 Open Access
Notes ; This work was supported by imec's Industrial Affiliation Program. D. Verreck acknowledges the support of a PhD stipend from IWT-Vlaanderen. ; Approved Most recent IF: 2.068
Call Number UA @ lucian @ c:irua:141481 Serial 4593
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Author Bizindavyi, J.; Verhulst, A.S.; Verreck, D.; Sorée, B.; Groeseneken, G.
Title Large variation in temperature dependence of band-to-band tunneling current in tunnel devices Type A1 Journal article
Year 2019 Publication IEEE electron device letters Abbreviated Journal Ieee Electr Device L
Volume 40 Issue 11 Pages 1864-1867
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract (down) The observation of a significant temperature-dependent variation in the ${I}$ – ${V}$ characteristics of tunneling devices is often interpreted as a signature of a trap-assisted-tunneling dominated current. In this letter, we use a ballistic 2D quantum-mechanical simulator, calibrated using the measured temperature-dependent ${I}$ – ${V}$ characteristics of Esaki diodes, to demonstrate that the temperature dependence of band-to-band tunneling (BTBT) current can vary significantly in both Esaki diodes and tunnel FETs. The variation of BTBT current with temperature is impacted by doping concentration, gate voltage, possible presence of a highly-doped pocket at the tunnel junction, and material.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000496192600040 Publication Date 2019-09-05
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0741-3106 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.048 Times cited Open Access
Notes Approved Most recent IF: 3.048
Call Number UA @ admin @ c:irua:164636 Serial 6306
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Author Raymenants, E.; Bultynck, O.; Wan, D.; Devolder, T.; Garello, K.; Souriau, L.; Thiam, A.; Tsvetanova, D.; Canvel, Y.; Nikonov, D.E.; Young, I.A.; Heyns, M.; Sorée, B.; Asselberghs, I.; Radu, I.; Couet, S.; Nguyen, V.D.
Title Nanoscale domain wall devices with magnetic tunnel junction read and write Type A1 Journal article
Year 2021 Publication Nature Electronics Abbreviated Journal
Volume 4 Issue 6 Pages 392-398
Keywords A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Abstract (down) The manipulation of fast domain wall motion in magnetic nanostructures could form the basis of novel magnetic memory and logic devices. However, current approaches for reading and writing domain walls require external magnetic fields, or are based on conventional magnetic tunnel junctions (MTJs) that are not compatible with high-speed domain wall motion. Here we report domain wall devices based on perpendicular MTJs that offer electrical read and write, and fast domain wall motion via spin-orbit torque. The devices have a hybrid free layer design that consists of platinum/cobalt (Pt/Co) or a synthetic antiferromagnet (Pt/Co/Ru/Co) into the free layer of conventional MTJs. We show that our devices can achieve good tunnelling magnetoresistance readout and efficient spin-transfer torque writing that is comparable to current magnetic random-access memory technology, as well as domain wall depinning efficiency that is similar to stand-alone materials. We also show that a domain wall conduit based on a synthetic antiferromagnet offers the potential for reliable domain wall motion and faster write speed compared with a device based on Pt/Co. Domain wall devices based on perpendicular magnetic tunnel junctions with a hybrid free layer design can offer electrical read and write, and fast domain wall motion driven via spin-orbit torque.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000665011500005 Publication Date 2021-06-23
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2520-1131 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited Open Access OpenAccess
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:179673 Serial 7003
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Author Andrikopoulos, D.; Sorée, B.; De Boeck, J.
Title Skyrmion-induced bound states on the surface of three-dimensional topological insulators Type A1 Journal article
Year 2016 Publication Journal of applied physics Abbreviated Journal J Appl Phys
Volume 119 Issue 119 Pages 193903
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract (down) The interaction between the surface of a 3D topological insulator and a skyrmion/anti-skyrmion structure is studied in order to investigate the possibility of electron confinement due to the skyrmion presence. Both hedgehog (Neel) and vortex (Bloch) skyrmions are considered. For the hedgehog skyrmion, the in-plane components cannot be disregarded and their interaction with the surface state of the topological insulator (TI) has to be taken into account. A semi-classical description of the skyrmion chiral angle is obtained using the variational principle. It is shown that both the hedgehog and the vortex skyrmion can induce bound states on the surface of the TI. However, the number and the properties of these states depend strongly on the skyrmion type and the skyrmion topological number N-Sk. The probability densities of the bound electrons are also derived where it is shown that they are localized within the skyrmion region. Published by AIP Publishing.
Address
Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000377718100013 Publication Date 2016-05-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-8979; 1089-7550 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.068 Times cited 8 Open Access
Notes ; ; Approved Most recent IF: 2.068
Call Number UA @ lucian @ c:irua:134607 Serial 4244
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Author Pourtois, G.; Lauwers, A.; Kittl, J.; Pantisano, L.; Sorée, B.; De Gendt, S.; Magnus, W.; Heyns, A.; Maex, K.
Title First-principle calculations on gate/dielectric interfaces : on the origin of work function shifts Type A1 Journal article
Year 2005 Publication Microelectronic engineering Abbreviated Journal Microelectron Eng
Volume 80 Issue Pages 272-279
Keywords A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract (down) The impact of interfacial chemistry occurring at dielectric/gate interface of P-MOS and N-MOS devices is reviewed through a quick literature survey. A specific emphasis is put on the way the bond polarization that occurs between a dielectric and a metal substrate impacts on the gate work function. First-principle simulations are then used to study the work function changes induced by dopant aggregation in nickel monosilicide metal gates. It is shown that the changes are a natural consequence of the variation of the interface polarization.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000231517000062 Publication Date 2005-06-05
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0167-9317; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.806 Times cited 31 Open Access
Notes Approved Most recent IF: 1.806; 2005 IF: 1.347
Call Number UA @ lucian @ c:irua:95095 Serial 1199
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Author Van de Put, M.L.; Vandenberghe, W.G.; Magnus, W.; Sorée, B.
Title An envelope function formalism for lattice-matched heterostructures Type A1 Journal article
Year 2015 Publication Physica: B : condensed matter Abbreviated Journal Physica B
Volume 470-471 Issue 470-471 Pages 69-75
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract (down) The envelope function method traditionally employs a single basis set which, in practice, relates to a single material because the k.p matrix elements are generally only known in a particular basis. In this work, we defined a basis function transformation to alleviate this restriction. The transformation is completely described by the known inter-band momentum matrix elements. The resulting envelope function equation can solve the electronic structure in lattice matched heterostructures without resorting to boundary conditions at the interface between materials, while all unit-cell averaged observables can be calculated as with the standard envelope function formalism. In the case of two coupled bands, this heterostructure formalism is equivalent to the standard formalism while taking position dependent matrix elements. (C) 2015 Elsevier B.V. All rights reserved
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000355149600011 Publication Date 2015-04-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0921-4526; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.386 Times cited 5 Open Access
Notes ; ; Approved Most recent IF: 1.386; 2015 IF: 1.319
Call Number c:irua:126397 Serial 95
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Author Lujan, G.S.; Magnus, W.; Sorée, B.; Ragnarsson, L.A.; Trojman, L.; Kubicek, S.; De Gendt, S.; Heyns, A.; De Meyer, K.
Title Barrier permeation effects on the inversion layer subband structure and its applications to the electron mobility Type A1 Journal article
Year 2005 Publication Microelectronic engineering Abbreviated Journal Microelectron Eng
Volume 80 Issue Pages 82-85
Keywords A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Abstract (down) The electron wave functions in the inversion layer are analyzed in the case where the dielectric barriers are not infinite. This forces the electron concentration closer to the interface silicon/oxide and reduces the subband energy. This treatment of the inversion layer is extended to the calculation of the electron mobility degradation due to remote Coulomb scattering on a high-k dielectric stacked transistor. The subband energy reduction leads to a decrease of the scattering charge needed to explain the experimental results. This model can also fit better the experimental data when compared with the case where no barrier permeation is considered.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000231517000021 Publication Date 2005-06-05
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0167-9317; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.806 Times cited 1 Open Access
Notes Approved Most recent IF: 1.806; 2005 IF: 1.347
Call Number UA @ lucian @ c:irua:102729 Serial 222
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Author Nourbakhsh, A.; Cantoro, M.; Klekachev, A.; Clemente, F.; Sorée, B.; van der Veen, M.H.; Vosch, T.; Stesmans, A.; Sels, B.; de Gendt, S.
Title Tuning the Fermi level of SiO2-supported single-layer graphene by thermal annealing Type A1 Journal article
Year 2010 Publication Journal Of Physical Chemistry C Abbreviated Journal J Phys Chem C
Volume 114 Issue 5 Pages 6894-6900
Keywords A1 Journal article; Electron Microscopy for Materials Science (EMAT);
Abstract (down) The effects of thermal annealing in inert Ar gas atmosphere of SiO2-supported, exfoliated single-layer graphene are investigated in this work. A systematic, reproducible change in the electronic properties of graphene is observed after annealing. The most prominent Raman features in graphene, the G and 2D peaks, change in accord to what is expected in the case of hole doping. The results of electrical characterization performed on annealed, back-gated field-effect graphene devices show that the neutrality point voltage VNP increases monotonically with the annealing temperature, confirming the occurrence of excess hole accumulation. No degradation of the structural properties of graphene is observed after annealing at temperatures as high as 400 °C. Thermal annealing of single-layer graphene in controlled Ar atmosphere can therefore be considered a technique to reproducibly modify the electronic structure of graphene by tuning its Fermi level.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000276562500002 Publication Date 2010-03-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1932-7447;1932-7455; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.536 Times cited 54 Open Access
Notes Approved Most recent IF: 4.536; 2010 IF: 4.524
Call Number UA @ lucian @ c:irua:89508 Serial 3757
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Author van Duijn, F.; Osca, J.; Sorée, B.
Title Skyrmion elongation, duplication, and rotation by spin-transfer torque under spatially varying spin current Type A1 Journal article
Year 2021 Publication Physical Review B Abbreviated Journal Phys Rev B
Volume 104 Issue 9 Pages 094426
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract (down) The effect of the spatially varying spin current on a skyrmion is numerically investigated. It is shown that an inhomogeneous current density induces an elongation of the skyrmion. This elongation can be controlled using current pulses of different strength and duration. Long current pulses lead to a splitting that forms two replicas of the initial skyrmion while for short pulses the elongated skyrmion relaxes back to its initial circular state through rotation in the MHz-GHz frequency range. The frequency is dependent on the strength of the damping coefficient.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000704236000002 Publication Date 2021-09-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited Open Access OpenAccess
Notes Approved Most recent IF: 3.836
Call Number UA @ admin @ c:irua:182467 Serial 7018
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Author Vermeulen, B.B.; Monteiro, M.G.; Giuliano, D.; Sorée, B.; Couet, S.; Temst, K.; Nguyen, V.D.
Title Magnetization-switching dynamics driven by chiral coupling Type A1 Journal article
Year 2024 Publication Physical review applied Abbreviated Journal
Volume 21 Issue 2 Pages 024050-11
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract (down) The Dzyaloshinskii-Moriya interaction (DMI) is known to play a central role in stabilizing chiral spin textures such as skyrmions and domain walls (DWs). Electrical manipulation of DW and skyrmion motion offers possibilities for next-generation, scalable and energy-efficient spintronic devices. However, achieving the full potential of these nanoscale devices requires overcoming several challenges, including reliable electrical write and read techniques for these magnetic objects, and addressing pinning and Joule-heating concerns. Here, through micromagnetic simulations and analytical modeling, we show that DMI can directly induce magnetization switching of a nanomagnet with perpendicular magnetic anisotropy (PMA). We find that the switching is driven by the interplay between the DMI-induced magnetic frustration and the PMA. By introducing magnetic tunnel junctions to electrically access and control the magnetization direction of the PMA nanomagnet, we first show the potential of this concept to enable high-density fieldfree spin-orbit torque magnetic random-access memory. Ultimately, we demonstrate that it offers a way of transferring and processing spin information for logic operation without relying on current-driven DW or skyrmion motion.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001187487900001 Publication Date 2024-02-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2331-7019 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.6 Times cited Open Access
Notes Approved Most recent IF: 4.6; 2024 IF: 4.808
Call Number UA @ admin @ c:irua:205518 Serial 9157
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Author Magnus, W.; Brosens, F.; Sorée, B.
Title Modeling drive currents and leakage currents : a dynamic approach Type A1 Journal article
Year 2009 Publication Journal of computational electronics Abbreviated Journal J Comput Electron
Volume 8 Issue 3/4 Pages 307-323
Keywords A1 Journal article; Condensed Matter Theory (CMT); Theory of quantum systems and complex systems
Abstract (down) The dynamics of electrons and holes propagating through the nano-scaled channels of modern semiconductor devices can be seen as a widespread manifestation of non-equilibrium statistical physics and its ruling principles. In this respect both the devices that are pushing conventional CMOS technology towards the final frontiers of Moores law and the upcoming set of alternative, novel nanostructures grounded on entirely new concepts and working principles, provide an almost unlimited playground for assessing physical models and numerical techniques emerging from classical and quantum mechanical non-equilibrium theory. In this paper we revisit the Boltzmann as well as the WignerBoltzmann equation which offers a valuable platform to study transport of charge carriers taking part in drive currents. We focus on a numerical procedure that regained attention recently as an alternative tool to solve the time-dependent Boltzmann equation for inhomogeneous systems, such as the channel regions of field-effect transistors, and we discuss its extension to the WignerBoltzmann equation. Furthermore, we pay attention to the calculation of tunneling leakage currents. The latter typically occurs in nano-scaled transistors when part of the carrier distribution sustaining the drive current is found to tunnel into the gate due the presence of an ultra-thin insulating barrier separating the gate from the channel region. In particular, we discuss the paradox related to the very existence of leakage currents established by electrons occupying quasi-bound states, while the (real) wave functions of the latter cannot carry net currents. Finally, we describe a simple model to resolve the paradox as well as to estimate gate currents provided the local carrier generation rates largely exceed the tunneling rates.
Address
Corporate Author Thesis
Publisher Place of Publication S.l. Editor
Language Wos 000208236100009 Publication Date 2009-09-28
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1569-8025;1572-8137; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.526 Times cited 4 Open Access
Notes Approved Most recent IF: 1.526; 2009 IF: NA
Call Number UA @ lucian @ c:irua:89503 Serial 2110
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Author Vanderveken, F.; Ahmad, H.; Heyns, M.; Sorée, B.; Adelmann, C.; Ciubotaru, F.
Title Excitation and propagation of spin waves in non-uniformly magnetized waveguides Type A1 Journal article
Year 2020 Publication Journal Of Physics D-Applied Physics Abbreviated Journal J Phys D Appl Phys
Volume 53 Issue 49 Pages 495006
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract (down) The characteristics of spin waves in ferromagnetic waveguides with non-uniform magnetization have been investigated for situations where the shape anisotropy field of the waveguide is comparable to the external bias field. Spin-wave generation was realized by the magnetoelastic effect by applying normal and shear strain components, as well as by the Oersted field emitted by an inductive antenna. The magnetoelastic excitation field has a non-uniform profile over the width of the waveguide because of the non-uniform magnetization orientation, whereas the Oersted field remains uniform. Using micromagnetic simulations, we indicate that both types of excitation fields generate quantised width modes with both odd and even mode numbers as well as tilted phase fronts. We demonstrate that these effects originate from the average magnetization orientation with respect to the main axes of the magnetic waveguide. Furthermore, it is indicated that the excitation efficiency of the second-order mode generally surpasses that of the first-order mode due to their symmetry. The relative intensity of the excited modes can be controlled by the strain state as well as by tuning the dimensions of the excitation area. Finally, we demonstrate that the nonreciprocity of spin-wave radiation due to the chirality of an Oersted field generated by an inductive antenna is absent for magnetoelastic spin-wave excitation.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000575331600001 Publication Date 2020-08-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-3727 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.4 Times cited 1 Open Access
Notes ; This work has been supported by imec's industrial affiliate program on beyond-CMOS logic. It has also received funding from the European Union's Horizon 2020 research and innovation program within the FET-OPEN project CHIRON under grant agreement No. 801055. F V acknowledges financial support from the Research Foundation -Flanders (FWO) through grant No. 1S05719N. ; Approved Most recent IF: 3.4; 2020 IF: 2.588
Call Number UA @ admin @ c:irua:172641 Serial 6515
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Author Vanderveken, F.; Mulkers, J.; Leliaert, J.; Van Waeyenberge, B.; Sorée, B.; Zografos, O.; Ciubotaru, F.; Adelmann, C.
Title Confined magnetoelastic waves in thin waveguides Type A1 Journal article
Year 2021 Publication Physical Review B Abbreviated Journal Phys Rev B
Volume 103 Issue 5 Pages 054439
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract (down) The characteristics of confined magnetoelastic waves in nanoscale ferromagnetic magnetostrictive waveguides have been investigated by a combination of analytical and numerical calculations. The presence of both magnetostriction and inverse magnetostriction leads to the coupling between confined spin waves and elastic Lamb waves. Numerical simulations of the coupled system have been used to extract the dispersion relations of the magnetoelastic waves as well as their mode profiles.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000627548800003 Publication Date 2021-02-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited Open Access OpenAccess
Notes Approved Most recent IF: 3.836
Call Number UA @ admin @ c:irua:177607 Serial 6976
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Author O'Regan, T.P.; Hurley, P.K.; Sorée, B.; Fischetti, M.V.
Title Modeling the capacitance-voltage response of In0.53Ga0.47As metal-oxide-semiconductor structures : charge quantization and nonparabolic corrections Type A1 Journal article
Year 2010 Publication Applied Physics Letters Abbreviated Journal Appl Phys Lett
Volume 96 Issue 21 Pages 213514,1-213514,3
Keywords A1 Journal article; Electron Microscopy for Materials Science (EMAT);
Abstract (down) The capacitance-voltage (C-V) characteristic is calculated for p-type In<sub>0.53</sub>Ga<sub>0.47</sub>As metal-oxide-semiconductor (MOS) structures based on a self-consistent PoissonSchrödinger solution. For strong inversion, charge quantization leads to occupation of the satellite valleys which appears as a sharp increase in the capacitance toward the oxide capacitance. The results indicate that the charge quantization, even in the absence of interface defects (D<sub>it</sub>), is a contributing factor to the experimental observation of an almost symmetric C-V response for In<sub>0.53</sub>Ga<sub>0.47</sub>As MOS structures. In addition, nonparabolic corrections are shown to enhance the depopulation of the Γ valley, shifting the capacitance increase to lower inversion charge densities.
Address
Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000278183200090 Publication Date 2010-05-28
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-6951; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.411 Times cited 26 Open Access
Notes Approved Most recent IF: 3.411; 2010 IF: 3.841
Call Number UA @ lucian @ c:irua:89509 Serial 2143
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Author Sethu, K.K.V.; Ghosh, S.; Couet, S.; Swerts, J.; Sorée, B.; De Boeck, J.; Kar, G.S.; Garello, K.
Title Optimization of tungsten beta-phase window for spin-orbit-torque magnetic random-access memory Type A1 Journal article
Year 2021 Publication Physical Review Applied Abbreviated Journal Phys Rev Appl
Volume 16 Issue 6 Pages 064009
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract (down) Switching induced by spin-orbit torque (SOT) is being vigorously explored, as it allows the control of magnetization using an in-plane current, which enables a three-terminal magnetic-tunnel-junction geometry with isolated read and write paths. This significantly improves the device endurance and the read stability, and allows reliable subnanosecond switching. Tungsten in the beta phase, beta-W, has the largest reported antidamping SOT charge-to-spin conversion ratio (theta(AD) approximate to -60%) for heavy metals. However, beta-W has a limitation when one is aiming for reliable technology integration: the beta phase is limited to a thickness of a few nanometers and enters the alpha phase above 4 nm in our samples when industry-relevant deposition tools are used. Here, we report our approach to extending the range of beta-W, while simultaneously improving the SOT efficiency by introducing N and O doping of W. Resistivity and XRD measurements confirm the extension of the beta phase from 4 nm to more than 10 nm, and transport characterization shows an effective SOT efficiency larger than -44.4% (reaching approximately -60% for the bulk contribution). In addition, we demonstrate the possibility of controlling and enhancing the perpendicular magnetic anisotropy of a storage layer (Co-Fe-B). Further, we integrate the optimized W(O, N) into SOT magnetic random-access memory (SOT-MRAM) devices and project that, for the same thickness of SOT material, the switching current decreases by 25% in optimized W(O, N) compared with our standard W. Our results open the path to using and further optimizing W for integration of SOT-MRAM technology.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000729005800002 Publication Date 2021-12-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2331-7019 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.808 Times cited Open Access Not_Open_Access
Notes Approved Most recent IF: 4.808
Call Number UA @ admin @ c:irua:184832 Serial 7007
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Author Toledano-Luque, M.; Matagne, P.; Sibaja-Hernandez, A.; Chiarella, T.; Ragnarsson, L.-A.; Sorée, B.; Cho, M.; Mocuta, A.; Thean, A.
Title Superior reliability of junctionless pFinFETs by reduced oxide electric field Type A1 Journal article
Year 2014 Publication IEEE electron device letters Abbreviated Journal Ieee Electr Device L
Volume 35 Issue 12 Pages 1179-1181
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract (down) Superior reliability of junctionless (JL) compared with inversion-mode field-effect transistors (FETs) is experimentally demonstrated on bulk FinFET wafers. The reduced negative bias temperature instability (NBTI) of JL pFETs outperforms the previously reported best NBTI reliability data obtained with Si channel devices and guarantees 10-year lifetime at typical operating voltages and high temperature. This behavior is understood through the reduced oxide electric field and lessened interaction between charge carriers and oxide traps during device operation. These findings encourage the investigation of JL devices with alternative channels as a promising alternative for 7-nm technology nodes meeting reliability targets.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000345575400006 Publication Date 2014-10-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0741-3106;1558-0563; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.048 Times cited 13 Open Access
Notes ; This work was supported by the imec's Core Partner Program. The review of this letter was arranged by Editor J. Schmitz. ; Approved Most recent IF: 3.048; 2014 IF: 2.754
Call Number UA @ lucian @ c:irua:122192 Serial 3378
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Author Kenawy, A.; Magnus, W.; Sorée, B.
Title Flux quantization and Aharonov-Bohm effect in superconducting rings Type A1 Journal article
Year 2018 Publication Journal of superconductivity and novel magnetism Abbreviated Journal J Supercond Nov Magn
Volume 31 Issue 5 Pages 1351-1357
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract (down) Superconductivity is a macroscopic coherent state exhibiting various quantum phenomena such as magnetic flux quantization. When a superconducting ring is placed in a magnetic field, a current flows to expel the field from the ring and to ensure that the enclosed flux is an integer multiple of h/(2|e|). Although the quantization of magnetic flux in ring structures is extensively studied in literature, the applied magnetic field is typically assumed to be homogeneous, implicitly implying an interplay between field expulsion and flux quantization. Here, we propose to decouple these two effects by employing an Aharonov-Bohm-like structure where the superconducting ring is threaded by a magnetic core (to which the applied field is confined). Although the magnetic field vanishes inside the ring, the formation of vortices takes place, corresponding to a change in the flux state of the ring. The time evolution of the density of superconducting electrons is studied using the time-dependent Ginzburg-Landau equations.
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000429354100010 Publication Date 2017-10-09
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1557-1939 ISBN Additional Links UA library record; WoS full record
Impact Factor 1.18 Times cited Open Access
Notes ; ; Approved Most recent IF: 1.18
Call Number UA @ lucian @ c:irua:150742UA @ admin @ c:irua:150742 Serial 4969
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Author Cantoro, M.; Klekachev, A.V.; Nourbakhsh, A.; Sorée, B.; Heyns, M.M.; de Gendt, S.
Title Long-wavelength, confined optical phonons in InAs nanowires probed by Raman spectroscopy Type A1 Journal article
Year 2011 Publication European physical journal : B : condensed matter and complex systems Abbreviated Journal Eur Phys J B
Volume 79 Issue 4 Pages 423-428
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract (down) Strongly confined nano-systems, such as one-dimensional nanowires, feature deviations in their structural, electronic and optical properties from the corresponding bulk. In this work, we investigate the behavior of long-wavelength, optical phonons in vertical arrays of InAs nanowires by Raman spectroscopy. We attribute the main changes in the spectral features to thermal anharmonicity, due to temperature effects, and rule out the contribution of quantum confinement and Fano resonances. We also observe the appearance of surface optical modes, whose details allow for a quantitative, independent estimation of the nanowire diameter. The results shed light onto the mechanisms of lineshape change in low-dimensional InAs nanostructures, and are useful to help tailoring their electronic and vibrational properties for novel functionalities.
Address
Corporate Author Thesis
Publisher Place of Publication Berlin Editor
Language Wos 000288120600005 Publication Date 2011-02-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1434-6028;1434-6036; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.461 Times cited 10 Open Access
Notes ; ; Approved Most recent IF: 1.461; 2011 IF: 1.534
Call Number UA @ lucian @ c:irua:89502 Serial 1841
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Author Pham, A.-T.; Zhao, Q.-T.; Jungemann, C.; Meinerzhagen, B.; Mantl, S.; Sorée, B.; Pourtois, G.
Title Comparison of strained SiGe heterostructure-on-insulator (0 0 1) and (1 1 0) PMOSFETs : CV characteristics, mobility, and ON current Type A1 Journal article
Year 2011 Publication Solid state electronics Abbreviated Journal Solid State Electron
Volume 65-66 Issue Pages 64-71
Keywords A1 Journal article; Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract (down) Strained SiGe heterostructure-on-insulator (0 0 1) and (1 1 0) PMOSFETs are investigated including important aspects like CV characteristics, mobility, and ON current. The simulations are based on the self-consistent solution of 6 × 6 k · p Schrödinger Equation, multi subband Boltzmann Transport Equation and Poisson Equation, and capture size quantization, strain, crystallographic orientation, and SiGe alloy effects on a solid physical basis. The simulation results are validated by comparison with different experimental data sources. The simulation results show that the strained SiGe HOI PMOSFET with (1 1 0) surface orientation has a higher gate capacitance and a much higher mobility and ON current compared to a similar device with the traditional (0 0 1) surface orientation.
Address
Corporate Author Thesis
Publisher Place of Publication Oxford Editor
Language Wos 000297182700012 Publication Date 2011-07-29
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0038-1101; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.58 Times cited 2 Open Access
Notes ; ; Approved Most recent IF: 1.58; 2011 IF: 1.397
Call Number UA @ lucian @ c:irua:92866 Serial 433
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Author Verreck, D.; Verhulst, A.S.; Van de Put, M.L.; Sorée, B.; Collaert, N.; Mocuta, A.; Thean, A.; Groeseneken, G.
Title Uniform strain in heterostructure tunnel field-effect transistors Type A1 Journal article
Year 2016 Publication IEEE electron device letters Abbreviated Journal Ieee Electr Device L
Volume 37 Issue 37 Pages 337-340
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract (down) Strain can strongly impact the performance of III-V tunnel field-effect transistors (TFETs). However, previous studies on homostructure TFETs have found an increase in ON-current to be accompanied with a degradation of subthreshold swing. We perform 30-band quantum mechanical simulations of staggered heterostructure p-n-i-n TFETs submitted to uniaxial and biaxial uniform stress and find the origin of the subthreshold degradation to be a reduction of the density of states in the strained case. We apply an alternative configuration including a lowly doped pocket in the source, which allows to take full benefit of the strain-induced increase in ON-current.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000372372100026 Publication Date 2016-01-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0741-3106 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.048 Times cited 17 Open Access
Notes ; This work was supported by the imec Industrial Affiliation Program. The work of D. Verreck was supported by the Agency for Innovation by Science and Technology in Flanders. The review of this letter was arranged by Editor Z. Chen. ; Approved Most recent IF: 3.048
Call Number UA @ lucian @ c:irua:133207 Serial 4271
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Author Sethu, K.K.V.; Yasin, F.; Swerts, J.; Sorée, B.; De Boeck, J.; Kar, G.S.; Garello, K.; Couet, S.
Title Spin-orbit torque vector quantification in nanoscale magnetic tunnel junctions Type A1 Journal article
Year 2024 Publication ACS nano Abbreviated Journal
Volume 18 Issue 21 Pages 13506-13516
Keywords A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Abstract (down) Spin-orbit torques (SOT) allow ultrafast, energy-efficient toggling of magnetization state by an in-plane charge current for applications such as magnetic random-access memory (SOT-MRAM). Tailoring the SOT vector comprising of antidamping (T-AD) and fieldlike (T-FL) torques could lead to faster, more reliable, and low-power SOT-MRAM. Here, we establish a method to quantify the longitudinal (T-AD) and transverse (T-FL) components of the SOT vector and its efficiency chi(AD) and chi(FL), respectively, in nanoscale three-terminal SOT magnetic tunnel junctions (SOT-MTJ). Modulation of nucleation or switching field (B-SF) for magnetization reversal by SOT effective fields (B-SOT) leads to the modification of SOT-MTJ hysteresis loop behavior from which chi(AD) and chi(FL) are quantified. Surprisingly, in nanoscale W/CoFeB SOT-MTJ, we find chi(FL) to be (i) twice as large as chi(AD) and (ii) 6 times as large as chi(FL) in micrometer-sized W/CoFeB Hall-bar devices. Our quantification is supported by micromagnetic and macrospin simulations which reproduce experimental SOT-MTJ Stoner-Wohlfarth astroid behavior only for chi(FL) > chi(AD). Additionally, from the threshold current for current-induced magnetization switching with a transverse magnetic field, we show that in SOT-MTJ, T-FL plays a more prominent role in magnetization dynamics than T-AD. Due to SOT-MRAM geometry and nanodimensionality, the potential role of nonlocal spin Hall spin current accumulated adjacent to the SOT-MTJ in the mediation of T-FL and chi(FL) amplification merits to be explored.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001226121700001 Publication Date 2024-05-15
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1936-0851 ISBN Additional Links UA library record; WoS full record
Impact Factor 17.1 Times cited Open Access
Notes Approved Most recent IF: 17.1; 2024 IF: 13.942
Call Number UA @ admin @ c:irua:205980 Serial 9173
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