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	Author	Akande, S.O.; Samanta, B.; Sevik, C.; Cakir, D.
	Title	First-principles investigation of mechanical and thermal properties of M Al B (M = Mo, W), Cr₂ AlB₂, and Ti₂ In B₂			Type	A1 Journal article
	Year	2023	Publication	Physical review applied	Abbreviated Journal
	Volume	20	Issue	4	Pages	044064-17
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	The atomically laminated layered ternary transition-metal borides (the MAB phases) have demonstrated outstanding properties and have been applied in various fields. Understanding their thermal and mechanical properties is critical to determining their applicability in various fields such as high-temperature applications. To achieve this, we conducted first-principles calculations based on density-functional theory and the quasiharmonic approximation to determine the thermal expansion coefficients, Gruneisen parameters, bulk moduli, hardness, thermal conductivity, electron-phonon coupling parameters, and the structural and vibrational properties of MoAlB, WAlB, Cr2AlB2, and Ti2InB2. We found varying degrees of anisotropy in the thermal expansion and mechanical properties in spite of similarities in their crystal structures. MoAlB has a mild degree of anisotropy in its thermal expansion coefficient (TEC), while Cr2AlB2 and WAlB display the highest level of TEC anisotropy. We assessed various empirical models to calculate hardness and thermal conductivity, and correlated the calculated values with the material properties such as elastic moduli, Gruneisen parameter, Debye temperature, and type of bonding. Owing to their higher Gruneisen parameters, implying a greater degree of anharmonicity in lattice vibrations and lower phonon group velocities, MoAlB and WAlB have significantly lower lattice thermal conductivity values than those of Cr2AlB2 and Ti2InB2. The hardness and lattice thermal conductivity of MAB phases can be predicted with high accuracy if one utilizes an appropriate model.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	001106456600003	Publication Date	2023-10-25
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2331-7019	ISBN		Additional Links	UA library record; WoS full record
	Impact Factor		Times cited		Open Access
	Notes				Approved	no
	Call Number	UA @ admin @ c:irua:202078			Serial	9037
Permanent link to this record



	Author	Foltyn, M.; Norowski, K.; Wyszynski, M.J.; De Arruda, A.S.; Milošević, M.V.; Zgirski, M.
	Title	Probing confined vortices with a superconducting nanobridge			Type	A1 Journal article
	Year	2023	Publication	Physical review applied	Abbreviated Journal
	Volume	19	Issue	4	Pages	044073-12
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	We realize a superconducting nanodevice in which vortex traps in the form of an aluminum square are integrated with a Dayem nanobridge. We perform field cooling of the traps arriving to different vortex configurations, dependent on the applied magnetic field, to demonstrate that the switching current of the bridge is highly sensitive to the presence and location of vortices in the trap. Our measurements exhibit unprecedented precision and ability to detect the first and successive vortex entries into all fabricated traps, from few hundred nm to 2 mu m in size. The experimental results are corroborated by Ginzburg-Landau simulations, which reveal the subtle yet crucial changes in the density of the superconducting condensate in the vicinity of the bridge with every additional vortex entry and relocation inside the trap. An ease of integration and simplicity make our design a convenient platform for studying dynamics of vortices in strongly confining geometries, involving a promise to manipulate vortex states electronically with simultaneous in situ control and monitoring.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000980861100007	Publication Date	2023-04-24
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2331-7019	ISBN		Additional Links	UA library record; WoS full record
	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:197356			Serial	8918
Permanent link to this record



	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	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
Permanent link to this record



	Author	Jiang, J.; Milošević, M.V.; Wang, Y.-L.; Xiao, Z.-L.; Peeters, F.M.; Chen, Q.-H.
	Title	Field-free superconducting diode in a magnetically nanostructured superconductor			Type	A1 Journal article
	Year	2022	Publication	Physical review applied	Abbreviated Journal	Phys Rev Appl
	Volume	18	Issue	3	Pages	034064-34069
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	A strong superconducting diode effect (SDE) is revealed in a thin superconducting film periodically nanostructured with magnetic dots. The SDE is caused by the current-activated dissipation mitigated by vortex-antivortex pairs (VAPs), which periodically nucleate under the dots, move and annihilate in the superconductor-eventually driving the system to the high-resistive state. Inversing the polarity of the applied current destimulates the nucleation of VAPs, the system remains superconducting up to far larger currents, leading to the pronounced diodic response. Our dissipative Ginzburg-Landau simulations detail the involved processes, and provide reliable geometric and parametric ranges for the experimental realiza-tion of such a nonvolatile superconducting diode, which operates in the absence of any applied magnetic field while being fluxonic by design.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000870234200001	Publication Date	2022-09-23
	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	2	Open Access	OpenAccess
	Notes				Approved	Most recent IF: 4.6
	Call Number	UA @ admin @ c:irua:191539			Serial	7307
Permanent link to this record



	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	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
Permanent link to this record



	Author	Tao, Z.H.; Dong, H.M.; Milošević, M.V.; Peeters, F.M.; Van Duppen, B.
	Title	Tailoring dirac plasmons via anisotropic dielectric environment by design			Type	A1 Journal article
	Year	2021	Publication	Physical Review Applied	Abbreviated Journal	Phys Rev Appl
	Volume	16	Issue	5	Pages	054030
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	Dirac plasmons in a two-dimensional (2D) crystal are strongly affected by the dielectric properties of the environment, due to interaction of their electric field lines with the surrounding medium. Using graphene as a 2D reservoir of free carriers, one can engineer a material configuration that provides an anisotropic environment to the plasmons. In this work, we discuss the physical properties of Dirac plasmons in graphene surrounded by an arbitrary anisotropic dielectric and exemplify how h-BN-based heterostructures can be designed to bear the required anisotropic characteristics. We calculate how dielec-tric anisotropy impacts the spatial propagation of the plasmons and find that an anisotropy-induced plasmon mode emerges, together with a damping pathway, that stem from the out-of-plane off-diagonal elements in the dielectric tensor. Furthermore, we find that one can create hyperbolic plasmons by inher-iting the dielectric hyperbolicity of the designed material environment. Strong control over plasmon propagation patterns can be realized in a similar manner. Finally, we show that in this way one can also control the polarization of the light-matter excitations that constitute the plasmon. Taken together, our results promote the design of the dielectric environment as an effective path to tailor the plasmonic response of graphene on the nanoscopic level.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000720372500002	Publication Date	2021-11-15
	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	1	Open Access	Not_Open_Access
	Notes				Approved	Most recent IF: 4.808
	Call Number	UA @ admin @ c:irua:184063			Serial	7028
Permanent link to this record



	Author	Yin, L.; Juneja, R.; Lindsay, L.; Pandey, T.; Parker, D.S.
	Title	Semihard iron-based permanent-magnet materials			Type	A1 Journal article
	Year	2021	Publication	Physical Review Applied	Abbreviated Journal	Phys Rev Appl
	Volume	15	Issue	2	Pages	024012
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	Permanent magnets generally require a favorable, but difficult-to-achieve combination of high magnetization, Curie point, and magnetic anisotropy. Thus there have been few, if any, viable permanent magnets developed since the 1982 discovery of Nd2Fe14B [M. Sagawa, S. Fujimura, H. Yamamoto, Y. Matsuura, and S. Hirosawa, J. Appl. Phys. 57, 4094 (1985)]. Here we point out, both by direct first-principles calculations on the iron carbides and silicides Fe5C2, Fe5SiC, and Fe7C3 as well as a discussion of recent experimental findings, that there are numerous rare-earth-free iron-rich potential permanent-magnet materials with sufficient intrinsic magnetic properties to reasonably achieve room-temperature energy products of 20-25 MG Oe. This is substantially better than the performance of the best available rare-earth-free magnets based on ferrite, as well as shape-anisotropy-employing alnico. These magnets could plausibly fill, at low cost, the present performance “gap” [J. M. D. Coey, Scr. Mater. 67, 524 (2012)] between the best rare-earth-free magnets and rare-earth magnets such as Nd2Fe14B and Sm-Co.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000614707800002	Publication Date	2021-02-05
	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:176624			Serial	6734
Permanent link to this record



	Author	Torsello, D.; Ummarino, G.A.; Bekaert, J.; Gozzelino, L.; Gerbaldo, R.; Tanatar, M.A.; Canfield, P.C.; Prozorov, R.; Ghigo, G.
	Title	Tuning the intrinsic anisotropy with disorder in the CaKFE₄As₄ superconductor			Type	A1 Journal article
	Year	2020	Publication	Physical Review Applied	Abbreviated Journal	Phys Rev Appl
	Volume	13	Issue	6	Pages	064046-64049
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	We report on the anisotropy of the London penetration depth of CaKFe4As4, discussing how it relates to its electronic structure and how it modifies under introduction of disorder, both chemically induced (by Ni substitution) and irradiation induced (by 3.5-MeV protons). Indeed, CaKFe4As4 is particularly suitable for the study of fundamental superconducting properties due to its stoichiometric composition, exhibiting clean-limit behavior in the pristine samples and having a fairly high critical temperature, T-c approximate to 35 K. The London penetration depth lambda(L) is measured with a microwave-coplanar-resonator technique that allows us to deconvolve the anisotropic contributions lambda(L,ab) and lambda(L,c) and obtain the anisotropy parameter gamma(lambda) = lambda(L,c)/lambda(L,ab). The gamma(lambda) (T) found for the undoped pristine sample is in good agreement with previous literature and is here compared to ab initio density-functional-theory and Eliashberg calculations. The dependence of gamma(lambda) (T) on both chemical and irradiation-induced disorder is discussed to highlight which method is more suitable to decrease the direction dependence of the electromagnetic properties while maintaining a high critical temperature. Lastly, the relevance of an intrinsic anisotropy such as gamma(lambda) on application-related anisotropic parameters (critical current, pinning) is discussed in light of the recent employment of CaKFe4As4 in the production of wires.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000540915800003	Publication Date	2020-06-19
	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	4	Open Access
	Notes	; This work was partially supported by the Italian Ministry of Education, University and Research (Project PRIN “HIBiSCUS,” Grant No. 201785KWLE). J.B. acknowledges the support of a postdoctoral fellowship of the Research Foundation-Flanders (FWO). The computational resources and services used for the first-principles calculations in this work were provided by the VSC (Flemish Supercomputer Center), funded by the FWO and the Flemish Government-department EWI. Work done at Ames Laboratory was supported by the U.S. Department of Energy, Office of Basic Energy Science, Division of Materials Sciences and Engineering. Ames Laboratory is operated for the U.S. Department of Energy by Iowa State University under Contract No. DE-AC02-07CH11358. G.A.U. acknowledges support from the MEPhI Academic Excellence Project (Contract No. 702.a03.21.0005). ;			Approved	Most recent IF: 4.6; 2020 IF: 4.808
	Call Number	UA @ admin @ c:irua:170178			Serial	6641
Permanent link to this record



	Author	Karaaslan, Y.; Yapicioglu, H.; Sevik, C.
	Title	Assessment of Thermal Transport Properties of Group-III Nitrides: A Classical Molecular Dynamics Study with Transferable Tersoff-Type Interatomic Potentials			Type	A1 Journal article
	Year	2020	Publication	Physical Review Applied	Abbreviated Journal	Phys Rev Appl
	Volume	13	Issue	3	Pages	034027
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	In this study, by means of classical molecular dynamics simulations, we investigate the thermal-transport properties of hexagonal single-layer, zinc-blend, and wurtzite phases of BN, AlN, and GaN crystals, which are very promising for the application and design of high-quality electronic devices. With this in mind, we generate fully transferable Tersoff-type empirical interatomic potential parameter sets by utilizing an optimization procedure based on particle-swarm optimization. The predicted thermal properties as well as the structural, mechanical, and vibrational properties of all materials are in very good agreement with existing experimental and first-principles data. The impact of isotopes on thermal transport is also investigated and between approximately 10 and 50% reduction in phonon thermal transport with random isotope distribution is observed in BN and GaN crystals. Our investigation distinctly shows that the generated parameter sets are fully transferable and very useful in exploring the thermal properties of systems containing these nitrides.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000518820200003	Publication Date	2020-03-10
	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; 2020 IF: 4.808
	Call Number	UA @ admin @ c:irua:193766			Serial	7508
Permanent link to this record



	Author	Sevik, C.; Çakir, D.
	Title	Tailoring Storage Capacity and Ion Kinetics in Ti2CO2/Graphene Heterostructures by Functionalization of Graphene			Type	A1 Journal article
	Year	2019	Publication	Physical review applied	Abbreviated Journal
	Volume	12	Issue	1	Pages	014001
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	Using first-principles calculations, we evaluate the electrochemical performance of heterostructures made up of Ti2CO2 and chemically modified graphene for Li batteries. We find that heteroatom doping and molecule intercalation have a significant impact on the storage capacity and Li migration barrier energies. While N and S doping do not improve the storage capacity, B doping together with molecule interaction make it possible to intercalate two layers of Li, which stick separately to the surface of Ti2CO2 and B-doped graphene. The calculated diffusion-barrier energies (E-diff), which are between 0.3 and 0.4 eV depending on Li concentration, are quite promising for fast charge and discharge rates. Besides, the predicted E-diff as much as 2 eV for the diffusion of the Li atom from the Ti2CO2 surface to the B-doped graphene surface significantly suppresses the interlayer Li migration, which diminishes the charge and discharge rates. The calculated volume and lattice parameter changes indicate that Ti2CO2/graphene hybrid structures exhibit cyclic stability against Li loading and unloading. Consequently, first-principles calculations we perform evidently highlight the favorable effect of molecular intercalation on the capacity improvement of ion batteries.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000473312000001	Publication Date	2019-07-01
	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		Times cited		Open Access
	Notes				Approved	no
	Call Number	UA @ admin @ c:irua:193755			Serial	8640
Permanent link to this record



	Author	de de Meux, A.J.; Pourtois, G.; Genoe, J.; Heremans, P.
	Title	Defects in amorphous semiconductors : the case of amorphous indium gallium zinc oxide			Type	A1 Journal article
	Year	2018	Publication	Physical review applied	Abbreviated Journal	Phys Rev Appl
	Volume	9	Issue	9	Pages	054039
	Keywords	A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
	Abstract	Based on a rational classification of defects in amorphous materials, we propose a simplified model to describe intrinsic defects and hydrogen impurities in amorphous indium gallium zinc oxide (a-IGZO). The proposed approach consists of organizing defects into two categories: point defects, generating structural anomalies such as metal-metal or oxygen-oxygen bonds, and defects emerging from changes in the material stoichiometry, such as vacancies and interstitial atoms. Based on first-principles simulations, it is argued that the defects originating from the second group always act as perfect donors or perfect acceptors. This classification simplifies and rationalizes the nature of defects in amorphous phases. In a-IGZO, the most important point defects are metal-metal bonds (or small metal clusters) and peroxides (O-O single bonds). Electrons are captured by metal-metal bonds and released by the formation of peroxides. The presence of hydrogen can lead to two additional types of defects: metal-hydrogen defects, acting as acceptors, and oxygen-hydrogen defects, acting as donors. The impact of these defects is linked to different instabilities observed in a-IGZO. Specifically, the diffusion of hydrogen and oxygen is connected to positive-and negative-bias stresses, while negative-bias illumination stress originates from the formation of peroxides.
	Address
	Corporate Author				Thesis
	Publisher	American Physical Society	Place of Publication	College Park, Md	Editor
	Language		Wos	000433070900003	Publication Date	2018-05-25
	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	7	Open Access	OpenAccess
	Notes				Approved	Most recent IF: 4.808
	Call Number	UA @ lucian @ c:irua:151497			Serial	5019
Permanent link to this record



	Author	Lu, A.K.A.; Houssa, M.; Luisier, M.; Pourtois, G.
	Title	Impact of layer alignment on the behavior of MoS₂-ZrS₂ tunnel field-effect transistors : an ab initio study			Type	A1 Journal article
	Year	2017	Publication	Physical review applied	Abbreviated Journal	Phys Rev Appl
	Volume	8	Issue	3	Pages	034017
	Keywords	A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
	Abstract	Tunnel field-effect transistors based on van der Waals heterostructures are emerging device concepts for low-power applications, auguring sub-60 mV/dec subthreshold swing values. In these devices, the channel is built from a stack of several different two-dimensional materials whose nature allows tailoring the band alignments and enables a good electrostatic control of the device. In this work, we propose a theoretical study of the variability of the performances of a MoS2-ZrS2 tunnel field-effect transistor induced by fluctuations of the relative position or the orientation of the layers. Our results indicate that although a steep subthreshold slope (20 mV/dec) is achievable, fluctuations in the relative orientation of the ZrS2 layer with respect to the MoS2 one lead to a significant variability in the tunneling current by about one decade. This arises from changes in the orbital overlap between the layers and from the modulation of the transport direction.
	Address
	Corporate Author				Thesis
	Publisher	American Physical Society	Place of Publication	College Park, Md	Editor
	Language		Wos	000411460400001	Publication Date	2017-09-22
	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	6	Open Access	OpenAccess
	Notes				Approved	Most recent IF: 4.808
	Call Number	UA @ lucian @ c:irua:146741			Serial	4785
Permanent link to this record



	Author	Juchtmans, R.; Guzzinati, G.; Verbeeck, J.
	Title	Extension of Friedel's law to vortex-beam diffraction			Type	A1 Journal article
	Year	2016	Publication	Physical Review A	Abbreviated Journal	Phys Rev A
	Volume	94	Issue	94	Pages	033858
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	Friedel's law states that the modulus of the Fourier transform of real functions is centrosymmetric, while the phase is antisymmetric. As a consequence of this, elastic scattering of plane-wave photons or electrons within the first-order Born-approximation, as well as Fraunhofer diffraction on any aperture, is bound to result in centrosymmetric diffraction patterns. Friedel's law, however, does not apply for vortex beams, and centrosymmetry in general is not present in their diffraction patterns. In this work we extend Friedel's law for vortex beams by showing that the diffraction patterns of vortex beams with opposite topological charge, scattered on the same two-dimensional potential, always are centrosymmetric to one another, regardless of the symmetry of the scattering object. We verify our statement by means of numerical simulations and experimental data. Our research provides deeper understanding in vortex-beam diffraction and can be used to design new experiments to measure the topological charge of vortex beams with diffraction gratings or to study general vortex-beam diffraction.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000384374500010	Publication Date	2016-09-30
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2469-9926	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	2.925	Times cited	13	Open Access
	Notes	The authors acknowledge support from the FWO (Aspirant Fonds Wetenschappelijk Onderzoek – Vlaanderen) and the EU under the Seventh Framework Program (FP7) under a contract for an Integrated Infrastructure Initiative, Reference No. 312483-ESTEEM2 and ERC Starting Grant No. 278510 VORTEX.; ECASJO_;			Approved	Most recent IF: 2.925
	Call Number	EMAT @ emat @ c:irua:137200UA @ admin @ c:irua:137200			Serial	4314
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	Author	Juchtmans, R.; Clark, L.; Lubk, A.; Verbeeck, J.
	Title	Spiral phase plate contrast in optical and electron microscopy			Type	A1 Journal article
	Year	2016	Publication	Physical review A	Abbreviated Journal	Phys Rev A
	Volume	94	Issue	94	Pages	023838
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	The use of phase plates in the back focal plane of a microscope is a well-established technique in optical microscopy to increase the contrast of weakly interacting samples and is gaining interest in electron microscopy as well. In this paper we study the spiral phase plate (SPP), also called helical, vortex, or two-dimensional Hilbert phase plate, which adds an angularly dependent phase of the form exp(iℓϕk) to the exit wave in Fourier space. In the limit of large collection angles, we analytically calculate that the average of a pair of l=+-1 SPP filtered images is directly proportional to the gradient squared of the exit wave, explaining the edge contrast previously seen in optical SPP work. We discuss the difference between a clockwise-anticlockwise pair of SPP filtered images and derive conditions under which the modulus of the wave's gradient can be seen directly from one SPP filtered image. This work provides the theoretical background to interpret images obtained with a SPP, thereby opening new perspectives for new experiments to study, for example, magnetic materials in an electron microscope.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000381882800011	Publication Date	2016-08-22
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2469-9926	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	2.925	Times cited	10	Open Access
	Notes	The authors acknowledge support from the FWO (Aspirant Fonds Wetenschappelijk Onderzoek – Vlaanderen) and the EU under the Seventh Framework Program (FP7) under a contract for an Integrated Infrastructure Initiative, Reference No. 312483-ESTEEM2 and ERC Starting Grant No. 278510 VORTEX.; ECASJO_			Approved	Most recent IF: 2.925
	Call Number	EMAT @ emat @ c:irua:140086			Serial	4418
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	Author	Klimin, S.N.; Tempere, J.; Verhelst, N.; Milošević, M.V.
	Title	Finite-temperature vortices in a rotating Fermi gas			Type	A1 Journal article
	Year	2016	Publication	Physical review A	Abbreviated Journal	Phys Rev A
	Volume	94	Issue	94	Pages	023620
	Keywords	A1 Journal article; Theory of quantum systems and complex systems; Condensed Matter Theory (CMT)
	Abstract	Vortices and vortex arrays have been used as a hallmark of superfluidity in rotated, ultracold Fermi gases. These superfluids can be described in terms of an effective field theory for a macroscopic wave function representing the field of condensed pairs, analogous to the Ginzburg-Landau theory for superconductors. Here we establish how rotation modifies this effective field theory, by rederiving it starting from the action of Fermi gas in the rotating frame of reference. The rotation leads to the appearance of an effective vector potential, and the coupling strength of this vector potential to the macroscopic wave function depends on the interaction strength between the fermions, due to a renormalization of the pair effective mass in the effective field theory. The mass renormalization derived here is in agreement with results of functional renormalization-group theory. In the extreme Bose-Einstein condensate regime, the pair effective mass tends to twice the fermion mass, in agreement with the physical picture of a weakly interacting Bose gas of molecular pairs. Then we use our macroscopic-wave-function description to study vortices and the critical rotation frequencies to form them. Equilibrium vortex state diagrams are derived and they are in good agreement with available results of the Bogoliubov-de Gennes theory and with experimental data.
	Address
	Corporate Author				Thesis
	Publisher	American Physical Society	Place of Publication	New York, N.Y.	Editor
	Language		Wos	000381473100001	Publication Date	2016-08-16
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2469-9934	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	2.925	Times cited	6	Open Access
	Notes	; We are grateful to G. C. Strinati and H. Warringa for valuable discussions. This research was supported by the Flemish Research Foundation Projects No. G.0115.12N, No. G.0119.12N, No. G.0122.12N, and No. G.0429.15N, by the Scientific Research Network of the Flemish Research Foundation, Grant No. WO.033.09N, and by the Research Fund of the University of Antwerp. ;			Approved	Most recent IF: 2.925
	Call Number	UA @ lucian @ c:irua:135686			Serial	4304
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	Author	Orlova, N.V.; Kuopanportti, P.; Milošević, M.V.
	Title	Skyrmionic vortex lattices in coherently coupled three-component Bose-Einstein condensates			Type	A1 Journal article
	Year	2016	Publication	Physical Review A	Abbreviated Journal	Phys Rev A
	Volume	94	Issue	2	Pages	023617
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	We show numerically that a harmonically trapped and coherently Rabi-coupled three-component Bose-Einstein condensate can host unconventional vortex lattices in its rotating ground state. The discovered lattices incorporate square and zig-zag patterns, vortex dimers and chains, and doubly quantized vortices, and they can be quantitatively classified in terms of a skyrmionic topological index, which takes into account the multicomponent nature of the system. The exotic ground-state lattices arise due to the intricate interplay of the repulsive density-density interactions and the Rabi couplings as well as the ubiquitous phase frustration between the components. In the frustrated state, domain walls in the relative phases can persist between some components even at strong Rabi coupling, while vanishing between others. Consequently, in this limit the three-component condensate effectively approaches a two-component condensate with only density-density interactions. At intermediate Rabi coupling strengths, however, we face unique vortex physics that occurs neither in the two-component counterpart nor in the purely density-density-coupled three-component system.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000381303800006	Publication Date	2016-08-12
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2469-9926;2469-9934;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	2.925	Times cited	16	Open Access
	Notes	; This work was supported by the Research Foundation Flanders (FWO). P. K. acknowledges financial support from the Emil Aaltonen Foundation, the Finnish Cultural Foundation, the Magnus Ehrnrooth Foundation, and the Technology Industries of Finland Centennial Foundation. The authors thank R. P. Anderson, E. Babaev, I. O. Cherednikov, V. R. Misko, T. P. Simula, and J. Tempere for useful comments and discussions. ;			Approved	Most recent IF: 2.925
	Call Number	UA @ lucian @ c:irua:144673			Serial	4688
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	Author	Clark, L.; Guzzinati, G.; Béché, A.; Lubk, A.; Verbeeck, J.
	Title	Symmetry-constrained electron vortex propagation			Type	A1 Journal article
	Year	2016	Publication	Physical review A	Abbreviated Journal	Phys Rev A
	Volume	93	Issue	93	Pages	063840
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	Electron vortex beams hold great promise for development in transmission electron microscopy but have yet to be widely adopted. This is partly due to the complex set of interactions that occur between a beam carrying orbital angular momentum (OAM) and a sample. Herein, the system is simplified to focus on the interaction between geometrical symmetries, OAM, and topology. We present multiple simulations alongside experimental data to study the behavior of a variety of electron vortex beams after interacting with apertures of different symmetries and investigate the effect on their OAM and vortex structure, both in the far field and under free-space propagation.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000378197200006	Publication Date	2016-06-23
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2469-9926	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	2.925	Times cited	7	Open Access
	Notes	L.C., A.B., G.G., and J.V. acknowledge funding from the European Research Council under the 7th Framework Program (FP7), ERC Starting Grant No. 278510—VORTEX. J.V. and A.L. acknowledge financial support from the European Union through the 7th Framework Program (FP7) under a contract for an Integrated Infrastructure Initiative (Reference No. 312483 ESTEEM2). The Qu-Ant-EM microscope was partly funded by the Hercules fund of the Flemish Government.; esteem2jra3; ECASJO;			Approved	Most recent IF: 2.925
	Call Number	c:irua:134086 c:irua:134086			Serial	4090
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	Author	Juchtmans, R.; Verbeeck, J.
	Title	Local orbital angular momentum revealed by spiral-phase-plate imaging in transmission-electron microscopy			Type	A1 Journal article
	Year	2016	Publication	Physical Review A	Abbreviated Journal	Phys Rev A
	Volume	93	Issue	93	Pages	023811
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	The orbital angular momentum (OAM) of light and matter waves is a parameter that has been getting increasingly more attention over the past couple of years. Beams with a well-defined OAM, the so-called vortex beams, are applied already in, e.g., telecommunication, astrophysics, nanomanipulation, and chiral measurements in optics and electron microscopy. Also, the OAM of a wave induced by the interaction with a sample has attracted a lot of interest. In all these experiments it is crucial to measure the exact (local) OAM content of the wave, whether it is an incoming vortex beam or an exit wave after interacting with a sample. In this work we investigate the use of spiral phase plates (SPPs) as an alternative to the programmable phase plates used in optics to measure OAM. We derive analytically how these can be used to study the local OAM components of any wave function. By means of numerical simulations we illustrate how the OAM of a pure vortex beam can be measured. We also look at a sum of misaligned vortex beams and show how, by using SPPs, the position and the OAM of each individual beam can be detected. Finally, we look at the OAM induced by a magnetic dipole on a free-electron wave and show how the SPP can be used to localize the magnetic poles and measure their “magnetic charge.” Although our findings can be applied to study the OAM of any wave function, our findings are of particular interest for electron microscopy where versatile programmable phase plates do not yet exist.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000369367700006	Publication Date	2016-02-06
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1050-2947;1094-1622;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	2.925	Times cited	12	Open Access
	Notes	The authors acknowledge support from the Aspirant Fonds Wetenschappelijk Onderzoek–Vlaanderen (FPO), the EU un- der the Seventh Framework Program (FP7) under a contract for an Integrated Infrastructure Initiative, Reference No. 312483- ESTEEM2, and the ERC Starting Grant 278510 VORTEX.; esteem2jra2 ECASJO;			Approved	Most recent IF: 2.925
	Call Number	c:irua:131613 c:irua:131613UA @ admin @ c:irua:131613			Serial	4030
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