NANOlab Center of Excellence literature database -- Query Results

	NANOlab Center of Excellence literature database Home \| Show All \| Simple Search \| Advanced Search	Login Quick Search: Field: contains: ...
	361–390 of 429 records found matching your query (RSS \| history):

Select All Deselect All

<< 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 >>

List View

Citations

Details

	Records
	Author	Berthelot, A.; Bogaerts, A.
	Title	Modeling of CO₂plasma: effect of uncertainties in the plasma chemistry			Type	A1 Journal article
	Year	2017	Publication	Plasma sources science and technology	Abbreviated Journal	Plasma Sources Sci T
	Volume	26	Issue	11	Pages	115002
	Keywords	A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
	Abstract	Low-temperature plasma chemical kinetic models are particularly important to the plasma community. These models typically require dozens of inputs, especially rate coefficients. The latter are not always precisely known and it is not surprising that the error on the rate coefficient data can propagate to the model output. In this paper, we present a model that uses N = 400 different combinations of rate coefficients based on the uncertainty attributed to each rate coefficient, giving a good estimation of the uncertainty on the model output due to the rate coefficients. We demonstrate that the uncertainty varies a lot with the conditions and the type of output. Relatively low uncertainties (about 15%) are found for electron density and temperature, while the uncertainty can reach more than an order of magnitude for the population of the vibrational levels in some cases and it can rise up to 100% for the CO2 conversion. The reactions that are mostly responsible for the largest uncertainties are identified. We show that the conditions of pressure, gas temperature and power density have a great effect on the uncertainty and on which reactions lead to this uncertainty. In all the cases tested here, while the absolute values may suffer from large uncertainties, the trends observed in previous modeling work are still valid. Finally, in accordance with the work of Turner, a number of ‘good practices’ is recommended.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000413216500002	Publication Date	2017-10-18
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1361-6595	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.302	Times cited	16	Open Access	OpenAccess
	Notes	We acknowledge financial support from the European Unions Seventh Framework Program for research, technological development and demonstration under grant agreement n◦ 606889. The calculations were carried out using the Turing HPC infrastructure at the CalcUA core facility of the Universiteit Antwerpen (UA), a division of the Flemish Supercomputer Center VSC, funded by the Hercules Foundation, the Flemish Government (department EWI) and the UA.			Approved	Most recent IF: 3.302
	Call Number	PLASMANT @ plasmant @c:irua:146879c:irua:146642			Serial	4758
Permanent link to this record



	Author	Saberi-Pouya, S.; Vazifehshenas, T.; Salavati-fard, T.; Farmanbar, M.
	Title	Anisotropic hybrid excitation modes in monolayer and double-layer phosphorene on polar substrates			Type	A1 Journal article
	Year	2017	Publication	Physical review B	Abbreviated Journal	Phys Rev B
	Volume	96	Issue	11	Pages	115402
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	We investigate the anisotropic hybrid surface optical (SO) phonon-plasmon dispersion relations in monolayer and double-layer phosphorene systems located on the polar substrates, such as SiO2, h-BN, and Al2O3. We calculate these hybrid modes by using the dynamical dielectric function in the random phase approximation in which the electron-electron interaction and long-range electric field generated by the substrate SO phonons via Frohlich interaction are taken into account. In the long-wavelength limit, we obtain some analytical expressions for the hybrid SO phonon-plasmon dispersion relations which agree with those obtained from the loss function. Our results indicate a strong anisotropy in SO phonon-plasmon modes, which are stronger along the light-mass direction in our heterostructures. Furthermore, we find that the type of substrate has a significant effect on the dispersion relations of the coupled modes. Importantly, the hybrid excitations are apparently sensitive to the misalignment and separation between layers in double-layer phosphorene.
	Address
	Corporate Author				Thesis
	Publisher	American Physical Society	Place of Publication	New York, N.Y	Editor
	Language		Wos	000408826200004	Publication Date	2017-09-01
	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	6	Open Access
	Notes	; ;			Approved	Most recent IF: 3.836
	Call Number	UA @ lucian @ c:irua:145665			Serial	4737
Permanent link to this record



	Author	De Beule, C.; Zarenia, M.; Partoens, B.
	Title	Transmission in graphene-topological insulator heterostructures			Type	A1 Journal article
	Year	2017	Publication	Physical review B	Abbreviated Journal	Phys Rev B
	Volume	95	Issue	95	Pages	115424
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	We investigate scattering of the topological surface state of a three-dimensional time-reversal invariant topological insulator when graphene is deposited on the topological-insulator surface. Specifically, we consider the (111) surface of a Bi2Se3-like topological insulator. We present a low-energy model for the graphene-topological insulator heterostructure and we calculate the transmission probability at zigzag and armchair edges of the deposited graphene, and the conductance through graphene nanoribbon barriers, and show that its features can be understood from antiresonances in the transmission probability.
	Address
	Corporate Author				Thesis
	Publisher	American Physical Society	Place of Publication	New York, N.Y	Editor
	Language		Wos	000399216700004	Publication Date	2017-03-22
	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	4	Open Access
	Notes	; The authors would like to thank B. Van Duppen for interesting discussions. This work was supported by the Flemish Research Foundation (FWO) through the Aspirant Fellowship of Christophe De Beule. ;			Approved	Most recent IF: 3.836
	Call Number	UA @ lucian @ c:irua:143652			Serial	4609
Permanent link to this record



	Author	Nascimento, J.S.; da Costa, D.R.; Zarenia, M.; Chaves, A.; Pereira, J.M., Jr.
	Title	Magnetic properties of bilayer graphene quantum dots in the presence of uniaxial strain			Type	A1 Journal article
	Year	2017	Publication	Physical review B	Abbreviated Journal	Phys Rev B
	Volume	96	Issue	11	Pages	115428
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	Using the tight-binding approach coupled with mean-field Hubbard model, we theoretically study the effect of mechanical deformations on the magnetic properties of bilayer graphene (BLG) quantum dots (QDs). Results are obtained for AA-and AB(Bernal)-stacked BLG QDs, considering different geometries (hexagonal, triangular and square shapes) and edge types (armchair and zigzag edges). In the absence of strain, our results show that (i) the magnetization is affected by taking different dot sizes only for hexagonal BLG QDs with zigzag edges, exhibiting different critical Hubbard interactions, and (ii) the magnetization does not depend on the interlayer hopping energies, except for the geometries with zigzag edges and AA stacking. In the presence of in-plane and uniaxial strain, for all geometries we obtain two different magnetization regimes depending on the applied strain amplitude. The appearance of such different regimes is due to the breaking of layer and sublattice symmetries in BLG QDs.
	Address
	Corporate Author				Thesis
	Publisher	American Physical Society	Place of Publication	New York, N.Y	Editor
	Language		Wos	000411077400008	Publication Date	2017-09-18
	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	4	Open Access
	Notes	; This work was financially supported by CNPq, FUNCAP, CAPES Foundation, the Flemish Science Foundation (FWO-Vl), and the Brazilian Program Science Without Borders (CsF). ;			Approved	Most recent IF: 3.836
	Call Number	UA @ lucian @ c:irua:146751			Serial	4788
Permanent link to this record



	Author	Han, F.W.; Xu, W.; Li, L.L.; Zhang, C.; Dong, H.M.; Peeters, F.M.
	Title	Electronic and transport properties of n-type monolayer black phosphorus at low temperatures			Type	A1 Journal article
	Year	2017	Publication	Physical review B	Abbreviated Journal	Phys Rev B
	Volume	95	Issue	95	Pages	115436
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	We present a detailed theoretical study of the electronic and transport properties of monolayer black phosphorus (BP). This study is motivated by recent experimental activities in investigating n-type few-layer BP systems. The electron density of states, the screening length, and the low-temperature electron mobility are calculated for monolayer BP (MLBP). In particular, the electron transport mobilities along the armchair and zigzag directions are examined on the basis of the momentum-balance equation derived from a semiclassical Boltzmann equation. The anisotropic electron mobilities in MLBP along different directions are demonstrated where the electron-impurity scattering is considered. Furthermore, we compare the results obtained from two electronic band structures of MLBP and find that the simplified model can describe quite rightly the electronic and transport properties of MLBP. This study is relevant to the application of few-layer BP based electronic systems as advanced electronic devices.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000399140700012	Publication Date	2017-03-27
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2469-9950	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.836	Times cited	12	Open Access
	Notes	National Natural Science Foundation of China, 11574319 11304316 11304317 11604380 ; Ministry of Science and Technology of the People's Republic of China, 2011YQ130018 ; Chinese Academy of Sciences;			Approved	Most recent IF: 3.836
	Call Number	CMT @ cmt @ c:irua:142431			Serial	4564
Permanent link to this record



	Author	Zarenia, M.; Neilson, D.; Partoens, B.; Peeters, F.M.
	Title	Wigner crystallization in transition metal dichalcogenides : a new approach to correlation energy			Type	A1 Journal article
	Year	2017	Publication	Physical review B	Abbreviated Journal	Phys Rev B
	Volume	95	Issue	95	Pages	115438
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	We introduce a new approach for the correlation energy of one- and two-valley two-dimensional electron gas (2DEG) systems. Our approach is based on an interpolation between two limits, a random phase approximation at high densities and a classical approach at low densities which gives excellent agreement with available Quantum Monte Carlo (QMC) calculations. The two-valley 2DEG model is introduced to describe the electron correlations in monolayer transition metal dichalcogenides (TMDs). We study the zero-temperature transition from a Fermi liquid to a quantum Wigner crystal phase in monolayer TMDs. Consistent with QMC, we find that electrons crystallize at r(s) = 31 in one-valley 2DEG. For two valleys, we predict Wigner crystallization at r(s) = 30, implying that valley degeneracy has little effect on the critical r(s), in contrast to an earlier claim.
	Address
	Corporate Author				Thesis
	Publisher	American Physical Society	Place of Publication	New York, N.Y	Editor
	Language		Wos	000399141200003	Publication Date	2017-03-30
	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	18	Open Access
	Notes	; This work was partially supported by the Flanders Research Foundation (FWO) and the Methusalem program of the Flemish government. D.N. acknowledges support by the University of Camerino FAR project CESEMN. ;			Approved	Most recent IF: 3.836
	Call Number	UA @ lucian @ c:irua:142428			Serial	4613
Permanent link to this record



	Author	Ramakers, M.; Medrano, J.A.; Trenchev, G.; Gallucci, F.; Bogaerts, A.
	Title	Revealing the arc dynamics in a gliding arc plasmatron: a better insight to improve CO₂conversion			Type	A1 Journal article
	Year	2017	Publication	Plasma sources science and technology	Abbreviated Journal	Plasma Sources Sci T
	Volume	26	Issue	12	Pages	125002
	Keywords	A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
	Abstract	A gliding arc plasmatron (GAP) is very promising for CO2 conversion into value-added chemicals, but to further improve this important application, a better understanding of the arc behavior is indispensable. Therefore, we study here for the first time the dynamic arc behavior of the GAP by means of a high-speed camera, for different reactor configurations and in a wide range of operating conditions. This allows us to provide a complete image of the behavior of the gliding arc. More specifically, the arc body shape, diameter, movement and rotation speed are analyzed and discussed. Clearly, the arc movement and shape relies on a number of factors, such as gas turbulence, outlet diameter, electrode surface, gas contraction and buoyance force. Furthermore, we also compare the experimentally measured arc movement to a state-of-the-art 3D-plasma model, which predicts the plasma movement and rotation speed with very good accuracy, to gain further insight in the underlying mechanisms. Finally, we correlate the arc dynamics with the CO2 conversion and energy efficiency, at exactly the same conditions, to explain the effect of these parameters on the CO2 conversion process. This work is important for understanding and optimizing the GAP for CO2 conversion.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000414675000001	Publication Date	2017-11-07
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1361-6595	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.302	Times cited	7	Open Access	OpenAccess
	Notes	This work was supported by the Belgian Federal Office for Science Policy (BELSPO) and the Fund for Scientific Research Flanders (FWO; grant numbers G.0383.16N and 11U5316N).			Approved	Most recent IF: 3.302
	Call Number	PLASMANT @ plasmant @c:irua:147023			Serial	4761
Permanent link to this record



	Author	Leliaert, J.; Mulkers, J.; De Clercq, J.; Coene, A.; Dvornik, M.; Van Waeyenberge, B.
	Title	Adaptively time stepping the stochastic Landau-Lifshitz-Gilbert equation at nonzero temperature: Implementation and validation in MuMax³			Type	A1 Journal article
	Year	2017	Publication	AIP advances	Abbreviated Journal	Aip Adv
	Volume	7	Issue	12	Pages	125010
	Keywords	A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
	Abstract	Thermal fluctuations play an increasingly important role in micromagnetic research relevant for various biomedical and other technological applications. Until now, it was deemed necessary to use a time stepping algorithm with a fixed time step in order to perform micromagnetic simulations at nonzero temperatures. However, Berkov and Gorn have shown in [D. Berkov and N. Gorn, J. Phys.: Condens. Matter,14, L281, 2002] that the drift term which generally appears when solving stochastic differential equations can only influence the length of the magnetization. This quantity is however fixed in the case of the stochastic Landau-Lifshitz-Gilbert equation. In this paper, we exploit this fact to straightforwardly extend existing high order solvers with an adaptive time stepping algorithm. We implemented the presented methods in the freely available GPU-accelerated micromagnetic software package MuMax3 and used it to extensively validate the presented methods. Next to the advantage of having control over the error tolerance, we report a twenty fold speedup without a loss of accuracy, when using the presented methods as compared to the hereto best practice of using Heun’s solver with a small fixed time step.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000418492500010	Publication Date	2017-12-11
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2158-3226	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	1.568	Times cited	13	Open Access
	Notes	This work was supported by the Fonds Wetenschappelijk Onderzoek (FWO-Vlaanderen) through Project No. G098917N and a postdoctoral fellowship (A.C.). J. L. is supported by the Ghent University Special Research Fund (BOF postdoctoral fellowship). We gratefully acknowl- edge the support of NVIDIA Corporation with the donation of the Titan Xp GPU used for this research.			Approved	Most recent IF: 1.568
	Call Number	CMT @ cmt @c:irua:147860			Serial	4799
Permanent link to this record



	Author	Michel, K.H.; Çakir, D.; Sevik, C.; Peeters, F.M.
	Title	Piezoelectricity in two-dimensional materials : comparative study between lattice dynamics and ab initio calculations			Type	A1 Journal article
	Year	2017	Publication	Physical review B	Abbreviated Journal	Phys Rev B
	Volume	95	Issue	95	Pages	125415
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	The elastic constant C-11 and piezoelectric stress constant e(1),(11) of two-dimensional (2D) dielectric materials comprising h-BN, 2H-MoS2, and other transition-metal dichalcogenides and dioxides are calculated using lattice dynamical theory. The results are compared with corresponding quantities obtained with ab initio calculations. We identify the difference between clamped-ion and relaxed-ion contributions with the dependence on inner strains which are due to the relative displacements of the ions in the unit cell. Lattice dynamics allows us to express the inner-strain contributions in terms of microscopic quantities such as effective ionic charges and optoacoustical couplings, which allows us to clarify differences in the piezoelectric behavior between h-BN and MoS2. Trends in the different microscopic quantities as functions of atomic composition are discussed.
	Address
	Corporate Author				Thesis
	Publisher	American Physical Society	Place of Publication	New York, N.Y	Editor
	Language		Wos	000396013400005	Publication Date	2017-03-11
	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	29	Open Access
	Notes	; The authors acknowledge useful discussions with L. Wirtz and A. Molina-Sanchez. This work was supported by the Methusalem program and the Fonds voor Wetenschappelijk Onderzoek-Vlaanderen. Computational resources were provided by HPC infrastructure of the University of Antwerp (CalcUA), a division of the Flemish Supercomputer Center (VSC), which is funded by the Hercules foundation. ;			Approved	Most recent IF: 3.836
	Call Number	UA @ lucian @ c:irua:142444			Serial	4603
Permanent link to this record



	Author	Mirzakhani, M.; Zarenia, M.; Vasilopoulos, P.; Ketabi, S.A.; Peeters, F.M.
	Title	Landau levels in biased graphene structures with monolayer-bilayer interfaces			Type	A1 Journal article
	Year	2017	Publication	Physical review B	Abbreviated Journal	Phys Rev B
	Volume	96	Issue	12	Pages	125430
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	The electron energy spectrum in monolayer-bilayer-monolayer and in bilayer-monolayer-bilayer graphene structures is investigated and the effects of a perpendicular magnetic field and electric bias are studied. Different types of monolayer-bilayer interfaces are considered as zigzag (ZZ) or armchair (AC) junctions which modify considerably the bulk Landau levels (LLs) when the spectra are plotted as a function of the center coordinate of the cyclotron orbit. Far away from the two interfaces, one obtains the well-known LLs for extended monolayer or bilayer graphene. The LL structure changes significantly at the two interfaces or junctions where the valley degeneracy is lifted for both types of junctions, especially when the distance between them is approximately equal to the magnetic length. Varying the nonuniform bias and the width of this junction-to-junction region in either structure strongly influence the resulting spectra. Significant differences exist between ZZ and AC junctions in both structures. The densities of states (DOSs) for unbiased structures are symmetric in energy whereas those for biased structures are asymmetric. An external bias creates interface LLs in the gaps between the LLs of the unbiased system in which the DOS can be quite small. Such a pattern of LLs can be probed by scanning tunneling microscopy.
	Address
	Corporate Author				Thesis
	Publisher	American Physical Society	Place of Publication	New York, N.Y	Editor
	Language		Wos	000411321800003	Publication Date	2017-09-21
	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	6	Open Access
	Notes	; This work was supported by the BOF-UA (Bijzonder Onderzoeks Fonds), the Canadian NSERC through Grant No. OGP0121756 (P.V.), and the Methusalem Program of the Flemish Government. ;			Approved	Most recent IF: 3.836
	Call Number	UA @ lucian @ c:irua:146746			Serial	4787
Permanent link to this record



	Author	Arsoski, V.V.; Grujić, M.M.; Čukarić, N.A.; Tadic, M.Z.; Peeters, F.M.
	Title	Normal and skewed phosphorene nanoribbons in combined magnetic and electric fields			Type	A1 Journal article
	Year	2017	Publication	Physical review B	Abbreviated Journal	Phys Rev B
	Volume	96	Issue	12	Pages	125434
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	The energy spectrum and eigenstates of single-layer black phosphorus nanoribbons in the presence of a perpendicular magnetic field and an in-plane transverse electric field are investigated by means of a tight-binding method, and the effect of different types of edges is examined analytically. A description based on a continuum model is proposed using an expansion of the tight-binding model in the long-wavelength limit. Thewave functions corresponding to the flatband part of the spectrum are obtained analytically and are shown to agree well with the numerical results from the tight-binding method for both narrow (10 nm) and wide (100 nm) nanoribbons. Analytical expressions for the critical magnetic field at which Landau levels are formed and the ranges of wave numbers in the dispersionless flatband segments in the energy spectra are derived. We examine the evolution of the Landau levels when an in-plane lateral electric field is applied, and we determine analytically how the edge states shift withmagnetic field. For wider nanoribbons, the conductance is shown to have a characteristic staircase shape in combined magnetic and electric fields. Some of the stairs in zigzag and skewed armchair nanoribbons originate from edge states that are found in the band gap.
	Address
	Corporate Author				Thesis
	Publisher	American Physical Society	Place of Publication	New York, N.Y	Editor
	Language		Wos	000411572400008	Publication Date	2017-09-25
	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	8	Open Access
	Notes	; This work was supported by Erasmus+, the Serbian Ministry of Education, Science and Technological Development, and the Flemish Science Foundation (FWO-Vl). ;			Approved	Most recent IF: 3.836
	Call Number	UA @ lucian @ c:irua:146738			Serial	4791
Permanent link to this record



	Author	Shayeganfar, F.; Vasu, K.S.; Nair, R.R.; Peeters, F.M.; Neek-Amal, M.
	Title	Monolayer alkali and transition-metal monoxides : MgO, CaO, MnO, and NiO			Type	A1 Journal article
	Year	2017	Publication	Physical review B	Abbreviated Journal
	Volume	95	Issue	14	Pages	144109
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	Two-dimensional crystals with strong interactions between layers has attracted increasing attention in recent years in a variety of fields. In particular, the growth of a single layer of oxide materials (e.g., MgO, CaO, NiO, and MnO) over metallic substrates were found to display different physical properties than their bulk. In this study, we report on the physical properties of a single layer of metallic oxide materials and compare their properties with their bulk and other two-dimensional (2D) crystals. We found that the planar structure of metallic monoxides are unstable whereas the buckled structures are thermodynamically stable. Also, the 2D-MnO and NiO exhibit different magnetic (ferromagnetic) and optical properties than their bulk, whereas band-gap energy and linear stiffness are found to be decreasing from NiO to MgO. Our findings provide insight into oxide thin-film technology applications.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000399792400001	Publication Date	2017-04-20
	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		Times cited	21	Open Access
	Notes				Approved	no
	Call Number	UA @ admin @ c:irua:152654			Serial	8278
Permanent link to this record



	Author	Mulkers, J.; Van Waeyenberge, B.; Milošević, M.V.
	Title	Effects of spatially engineered Dzyaloshinskii-Moriya interaction in ferromagnetic films			Type	A1 Journal article
	Year	2017	Publication	Physical review B	Abbreviated Journal	Phys Rev B
	Volume	95	Issue	95	Pages	144401
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	The Dzyaloshinskii-Moriya interaction (DMI) is a chiral interaction that favors formation of domain walls. Recent experiments and ab initio calculations show that there are multiple ways to modify the strength of the interfacially induced DMI in thin ferromagnetic films with perpendicular magnetic anisotropy. In this paper we reveal theoretically the effects of spatially varied DMI on the magnetic state in thin films. In such heterochiral 2D structures we report several emergent phenomena, ranging from the equilibrium spin canting at the interface between regions with different DMI, over particularly strong confinement of domain walls and skyrmions within high-DMI tracks, to advanced applications such as domain tailoring nearly at will, design of magnonic waveguides, and much improved skyrmion racetrack memory.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000399382100003	Publication Date	2017-04-03
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2469-9950	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.836	Times cited	60	Open Access
	Notes	Fonds Wetenschappelijk Onderzoek, G098917N ;			Approved	Most recent IF: 3.836
	Call Number	CMT @ cmt @ c:irua:141917			Serial	4534
Permanent link to this record



	Author	Takatsu, H.; Hernandez, O.; Yoshimune, W.; Prestipino, C.; Yamamoto, T.; Tassel, C.; Kobayashi, Y.; Batuk, D.; Shibata, Y.; Abakumov, A.M.; Brown, C.M.; Kageyama, H.
	Title	Cubic lead perovskite PbMoO3 with anomalous metallic behavior			Type	A1 Journal article
	Year	2017	Publication	Physical review B	Abbreviated Journal
	Volume	95	Issue	15	Pages	155105
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	A previously unreported Pb-based perovskite PbMoO3 is obtained by high-pressure and high-temperature synthesis. This material crystallizes in the Pm3m cubic structure at room temperature, making it distinct from typical Pb-based perovskite oxides with a structural distortion. PbMoO3 exhibits a metallic behavior down to 0.1 K with an unusual T-sublinear dependence of the electrical resistivity. Moreover, a large specific heat is observed at low temperatures accompanied by a peak in C-P/T-3 around 10 K, in marked contrast to the isostructural metallic system SrMoO3. These transport and thermal properties for PbMoO3, taking into account anomalously large Pb atomic displacements detected through diffraction experiments, are attributed to a low-energy vibrational mode, associated with incoherent off-centering of lone-pair Pb2+ cations. We discuss the unusual behavior of the electrical resistivity in terms of a polaronlike conduction, mediated by the strong coupling between conduction electrons and optical phonons of the local low-energy vibrational mode.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000440605700001	Publication Date	2017-04-04
	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		Times cited		Open Access
	Notes				Approved	no
	Call Number	UA @ admin @ c:irua:167288			Serial	7743
Permanent link to this record



	Author	Houben, K.; Couet, S.; Trekels, M.; Menendez, E.; Peissker, T.; Seo, J.W.; Hu, M.Y.; Zhao, J.Y.; Alp, E.E.; Roelants, S.; Partoens, B.; Milošević, M.V.; Peeters, F.M.; Bessas, D.; Brown, S.A.; Vantomme, A.; Temst, K.; Van Bael, M.J.
	Title	Lattice dynamics in Sn nanoislands and cluster-assembled films			Type	A1 Journal article
	Year	2017	Publication	Physical review B	Abbreviated Journal	Phys Rev B
	Volume	95	Issue	15	Pages	155413
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	To unravel the effects of phonon confinement, the influence of size and morphology on the atomic vibrations is investigated in Sn nanoislands and cluster-assembled films. Nuclear resonant inelastic x-ray scattering is used to probe the phonon densities of states of the Sn nanostructures which show significant broadening of the features compared to bulk phonon behavior. Supported by ab initio calculations, the broadening is attributed to phonon scattering and can be described within the damped harmonic oscillator model. Contrary to the expectations based on previous research, the appearance of high-energy modes above the cutoff energy is not observed. From the thermodynamic properties extracted from the phonon densities of states, it was found that grain boundary Sn atoms are bound by weaker forces than bulk Sn atoms.
	Address
	Corporate Author				Thesis
	Publisher	American Physical Society	Place of Publication	New York, N.Y	Editor
	Language		Wos	000401762400008	Publication Date	2017-04-11
	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	5	Open Access
	Notes	; This work was supported by the Research Foundation-Flanders (FWO) and the Concerted Research Action (GOA/14/007). The authors acknowledge Hercules stichting (Projects No. AKUL/13/19 and No. AKUL/13/25). K.H. and S.C. thank the FWO for financial support. T.P. acknowledges the IWT for financial support. S.R., M.V.M., and B.P. acknowledge TOPBOF funding of the University of Antwerp Research Fund. J.W.S. acknowledges Hercules Stichting (Project No. AKUL/13/19). The authors want to thank R. Lieten for help with the XRD measurements and T. Picot for fruitful discussions. The authors gratefully acknowledge R. Ruffer and A. I. Chumakov for fruitful discussions and the European Synchrotron Radiation Facility for the measurement of the SnO<INF>2</INF> powder at the Nuclear Resonance beamline (ID-18). This research used resources of the Advanced Photon Source, a US Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. ;			Approved	Most recent IF: 3.836
	Call Number	UA @ lucian @ c:irua:144305			Serial	4667
Permanent link to this record



	Author	Li, L.L.; Moldovan, D.; Xu, W.; Peeters, F.M.
	Title	Electronic properties of bilayer phosphorene quantum dots in the presence of perpendicular electric and magnetic fields			Type	A1 Journal article
	Year	2017	Publication	Physical review B	Abbreviated Journal	Phys Rev B
	Volume	96	Issue	15	Pages	155425
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	Using the tight-binding approach, we investigate the electronic properties of bilayer phosphorene (BLP) quantum dots (QDs) in the presence of perpendicular electric and magnetic fields. Since BLP consists of two coupled phosphorene layers, it is of interest to examine the layer-dependent electronic properties of BLP QDs, such as the electronic distributions over the two layers and the so-produced layer-polarization features, and to see how these properties are affected by the magnetic field and the bias potential. We find that in the absence of a bias potential only edge states are layer polarized while the bulk states are not, and the layer-polarization degree (LPD) of the unbiased edge states increases with increasing magnetic field. However, in the presence of a bias potential both the edge and bulk states are layer polarized, and the LPD of the bulk (edge) states depends strongly (weakly) on the interplay of the bias potential and the interlayer coupling. At high magnetic fields, applying a bias potential renders the bulk electrons in a BLP QD to be mainly distributed over the top or bottom layer, resulting in layer-polarized bulk Landau levels (LLs). In the presence of a large bias potential that can drive a semiconductor-to-semimetal transition in BLP, these bulk LLs exhibit different magnetic-field dependences, i.e., the zeroth LLs exhibit a linearlike dependence on the magnetic field while the other LLs exhibit a square-root-like dependence.
	Address
	Corporate Author				Thesis
	Publisher	American Physical Society	Place of Publication	New York, N.Y	Editor
	Language		Wos	000412699800005	Publication Date	2017-10-10
	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	28	Open Access
	Notes	; This work was financially supported by the Flemish Science Foundation (FWO-Vl), the National Natural Science Foundation of China (Grant No. 11574319), and the Chinese Academy of Sciences. ;			Approved	Most recent IF: 3.836
	Call Number	UA @ lucian @ c:irua:146686			Serial	4782
Permanent link to this record



	Author	Mirzakhani, M.; Zarenia, M.; Vasilopoulos, P.; Peeters, F.M.
	Title	Electrostatically confined trilayer graphene quantum dots			Type	A1 Journal article
	Year	2017	Publication	Physical review B	Abbreviated Journal
	Volume	95	Issue	15	Pages	155434
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	Electrically gating of trilayer graphene (TLG) opens a band gap offering the possibility to electrically engineer TLG quantum dots. We study the energy levels of such quantum dots and investigate their dependence on a perpendicular magnetic field B and different types of stacking of the graphene layers. The dots are modeled as circular and confined by a truncated parabolic potential which can be realized by nanostructured gates or position-dependent doping. The energy spectra exhibit the intervalley symmetry E-K(e) (m) = -E (h)(K') (m) for the electron (e) and hole (h) states, where m is the angular momentum quantum number and K and K' label the two valleys. The electron and hole spectra for B = 0 are twofold degenerate due to the intervalley symmetry E-K (m) = E-K' [-(m + 1)]. For both ABC [alpha = 1.5 (1.2) for large (small) R] and ABA (alpha = 1) stackings, the lowest-energy levels show approximately a R-alpha dependence on the dot radius R in contrast with the 1/R-3 one for ABC-stacked dots with infinite-mass boundary. As functions of the field B, the oscillator strengths for dipole-allowed transitions differ drastically for the two types of stackings.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000399797200003	Publication Date	2017-04-22
	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		Times cited	6	Open Access
	Notes				Approved	no
	Call Number	UA @ admin @ c:irua:152652			Serial	7878
Permanent link to this record



	Author	Kong, L.; Wang, W.; Murphy, A.B.; Xia, G.
	Title	Numerical analysis of direct-current microdischarge for space propulsion applications using the particle-in-cell/Monte Carlo collision (PIC/MCC) method			Type	A1 Journal article
	Year	2017	Publication	Journal of physics: D: applied physics	Abbreviated Journal	J Phys D Appl Phys
	Volume	50	Issue	16	Pages	165203
	Keywords	A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
	Abstract	Microdischarges are an important type of plasma discharge that possess several unique characteristics, such as the presence of a stable glow discharge, high plasma density and intense excimer radiation, leading to several potential applications. The intense and controllable gas heating within the extremely small dimensions of microdischarges has been exploited in microthruster technologies by incorporating a micro-nozzle to generate the thrust. This kind of microthruster has a significantly improved specific impulse performance compared to conventional cold gas thrusters, and can meet the requirements arising from the emerging development and application of micro-spacecraft. In this paper, we performed a self-consistent 2D particle-in-cell simulation, with a Monte Carlo collision model, of a microdischarge operating in a prototype micro-plasma thruster with a hollow cylinder geometry and a divergent micro-nozzle. The model takes into account the thermionic electron emission including the Schottky effect, the secondary electron emission due to cathode bombardment by the plasma ions, several different collision processes, and a non-uniform argon background gas density in the cathode-anode gap. Results in the high-pressure (several hundreds of Torr), high-current (mA) operating regime showing the behavior of the plasma density, potential distribution, and energy flux towards the hollow cathode and anode are presented and discussed. In addition, the results of simulations showing the effect of different argon gas pressures, cathode material work function and discharge voltage on the operation of the microdischarge thruster are presented. Our calculated properties are compared with experimental data under similar conditions and qualitative and quantitative agreements are reached.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	London	Editor
	Language		Wos	000398856300001	Publication Date	2017-02-22
	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	2.588	Times cited	8	Open Access	OpenAccess
	Notes				Approved	Most recent IF: 2.588
	Call Number	UA @ lucian @ c:irua:143642			Serial	4674
Permanent link to this record



	Author	Zhang, Q.-Z.; Tinck, S.; de Marneffe, J.-F.; Zhang, L.; Bogaerts, A.
	Title	Mechanisms for plasma cryogenic etching of porous materials			Type	A1 Journal article
	Year	2017	Publication	Applied physics letters	Abbreviated Journal	Appl Phys Lett
	Volume	111	Issue	17	Pages	173104
	Keywords	A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
	Abstract	Porous materials are commonly used in microelectronics, as they can meet the demand for continuously shrinking electronic feature dimensions. However, they are facing severe challenges in plasma etching, due to plasma induced damage. In this paper, we present both the plasma characteristics and surface processing during the etching of porous materials. We explain how the damage occurs in the porous material during plasma etching for a wide range of chuck temperatures and the responsible mechanism for plasma damage-free etching at cryogenic temperature, by a combination of experiments and numerical modeling.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000413863400032	Publication Date	2017-10-23
	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	2	Open Access	OpenAccess
	Notes	We acknowledge the support from Marie Skłodowska- Curie actions (Grant Agreement-702604). This work was carried out in part using the Turing HPC infrastructure at the CalcUA core facility of Universiteit Antwerpen, a division of the Flemish Supercomputer Center VSC, funded by the Hercules Foundation, the Flemish Government (department EWI), and the University of Antwerp. L. Zhang and J.-F. de Marneffe acknowledge Dr. M. Cooke and A. Goodyear from Oxford Instruments Plasma Technology for processing the samples at their Yatton facility in the United Kingdom.			Approved	Most recent IF: 3.411
	Call Number	PLASMANT @ plasmant @c:irua:147022			Serial	4762
Permanent link to this record



	Author	Augustyns, V.; van Stiphout, K.; Joly, V.; Lima, T.A.L.; Lippertz, G.; Trekels, M.; Menendez, E.; Kremer, F.; Wahl, U.; Costa, A.R.G.; Correia, J.G.; Banerjee, D.; Gunnlaugsson, H.P.; von Bardeleben, J.; Vickridge, I.; Van Bael, M.J.; Hadermann, J.; Araujo, J.P.; Temst, K.; Vantomme, A.; Pereira, L.M.C.
	Title	Evidence of tetragonal distortion as the origin of the ferromagnetic ground state in gamma-Fe nanoparticles			Type	A1 Journal article
	Year	2017	Publication	Physical review B	Abbreviated Journal	Phys Rev B
	Volume	96	Issue	17	Pages	174410
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	<script type='text/javascript'>document.write(unpmarked('gamma-Fe and related alloys are model systems of the coupling between structure and magnetism in solids. Since different electronic states (with different volumes and magnetic ordering states) are closely spaced in energy, small perturbations can alter which one is the actual ground state. Here, we demonstrate that the ferromagnetic state of gamma-Fe nanoparticles is associated with a tetragonal distortion of the fcc structure. Combining a wide range of complementary experimental techniques, including low-temperature Mossbauer spectroscopy, advanced transmission electron microscopy, and synchrotron radiation techniques, we unambiguously identify the tetragonally distorted ferromagnetic ground state, with lattice parameters a = 3.76(2) angstrom and c = 3.50(2) angstrom, and a magnetic moment of 2.45(5) mu(B) per Fe atom. Our findings indicate that the ferromagnetic order in nanostructured gamma-Fe is generally associated with a tetragonal distortion. This observation motivates a theoretical reassessment of the electronic structure of gamma-Fe taking tetragonal distortion into account.'));
	Address
	Corporate Author				Thesis
	Publisher	American Physical Society	Place of Publication	New York, N.Y	Editor
	Language		Wos	000414525200005	Publication Date	2017-11-07
	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	1	Open Access	OpenAccess
	Notes	; The authors thank the Fund for Scientific Research-Flanders, the Concerted Research Action of the KU Leuven (GOA/14/007), the KU Leuven BOF (STRT/14/002), the Hercules Foundation, the Portuguese Foundation for Science and Technology (CERN/FIS-NUC/0004/2015), and the European Union Seventh Framework through ENSAR2 (European Nuclear Science and Applications Research, Project No. 654002), and SPIRIT (Support of Public and Industrial Research Using Ion Beam Technology, Contract No. 227012). We acknowledge the European Synchrotron Radiation Facility (ESRF) for providing beam time (experiments 26-01-1018, 26-01-1057, 20-02-728, HC-1850, HC-2208), as well as C. Baehtz, N. Boudet, and N. Blancand for support during the experiments. We acknowledge the ISOLDE-CERN facility for providing beam time (experiment IS580) and technical assistance. The authors (L.M.C.P., F.K.) acknowledge the facilities and the scientific and technical assistance of the Australian Microscopy & Microanalysis Research Facility at the Centre for Advanced Microscopy, Australian National University. We also acknowledge the contribution of Prof. Mark Ridgway (Australian National University), who passed away before the work was completed. ;			Approved	Most recent IF: 3.836
	Call Number	UA @ lucian @ c:irua:147387			Serial	4873
Permanent link to this record



	Author	Leenaerts, O.; Vercauteren, S.; Partoens, B.
	Title	Band alignment of lateral two-dimensional heterostructures with a transverse dipole			Type	A1 Journal article
	Year	2017	Publication	Applied physics letters	Abbreviated Journal	Appl Phys Lett
	Volume	110	Issue	110	Pages	181602
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	It was recently shown that the electronic band alignment in lateral two-dimensional heterostructures is strongly dependent on the system geometry, such as heterostructure width and layer thickness. This is so even in the absence of polar edge terminations because of the appearance of an interface dipole between the two different materials. In this study, this work is expanded to include two-dimensional materials that possess an electronic dipole over their surface, i.e., in the direction transverse to the crystal plane. To this end, a heterostucture consisting of polar hydrofluorinated graphene and non-polar graphane layers is studied with first-principles calculations. As for nonpolar heterostructures, a significant geometry dependence is observed with two different limits for the band offset. For infinitely wide heterostructures, the potential step in the vacuum is equally divided over the two sides of the heterostructure, resulting in a finite potential step in the heterostructure. For infinitely thick heterostructure slabs, on the other hand, the band offset is reduced, similar to the three-dimensional case.
	Address
	Corporate Author				Thesis
	Publisher	American Institute of Physics	Place of Publication	New York, N.Y.	Editor
	Language		Wos	000400931900014	Publication Date	2017-05-01
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0003-6951; 1077-3118	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.411	Times cited	4	Open Access
	Notes	; This work was supported by the Fonds Wetenschappelijk Onderzoek (FWO-VI). The computational resources and services used in this work were provided by the VSC (Flemish Supercomputer Center), funded by the Hercules Foundation and the Flemish Government-department EWI. ;			Approved	Most recent IF: 3.411
	Call Number	UA @ lucian @ c:irua:143755			Serial	4586
Permanent link to this record



	Author	Khalilov, U.; Bogaerts, A.; Hussain, S.; Kovacevic, E.; Brault, P.; Boulmer-Leborgne, C.; Neyts, E.C.
	Title	Nanoscale mechanisms of CNT growth and etching in plasma environment			Type	A1 Journal article
	Year	2017	Publication	Journal of physics: D: applied physics	Abbreviated Journal	J Phys D Appl Phys
	Volume	50	Issue	50	Pages	184001
	Keywords	A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
	Abstract	Plasma-enhanced chemical deposition (PECVD) of carbon nanotubes has already been shown to allow chirality control to some extent. In PECVD, however, etching may occur simultaneously with the growth, and the occurrence of intermediate processes further significantly complicates the growth process. We here employ a computational approach with experimental support to study the plasma-based formation of Ni nanoclusters, Ni-catalyzed CNT growth and subsequent etching processes, in order to understand the underpinning nanoscale mechanisms. We find that hydrogen is the dominant factor in both the re-structuring of a Ni film and the subsequent appearance of Ni nanoclusters, as well as in the CNT nucleation and etching processes. The obtained results are compared with available theoretical and experimental studies and provide a deeper understanding of the occurring nanoscale mechanisms in plasma-assisted CNT nucleation and growth.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000398300900001	Publication Date	2017-04-03
	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	2.588	Times cited	6	Open Access	OpenAccess
	Notes	UK gratefully acknowledges financial support from the Research Foundation – Flanders (FWO), Belgium (Grant No. 12M1315N). The work was carried out in part using the Turing HPC infrastructure of the CalcUA core facility of the Universiteit Antwerpen, a division of the Flemish Supercomputer Centre VSC, funded by the Hercules Foundation, the Flemish Government (department EWI) and the Universiteit Antwerpen. The authors also thank Prof A C T van Duin for sharing the ReaxFF code.			Approved	Most recent IF: 2.588
	Call Number	PLASMANT @ plasmant @ c:irua:141918			Serial	4533
Permanent link to this record



	Author	Petrovic, M.D.; Milovanović, S.P.; Peeters, F.M.
	Title	Scanning gate microscopy of magnetic focusing in graphene devices : quantum versus classical simulation			Type	A1 Journal article
	Year	2017	Publication	Nanotechnology	Abbreviated Journal	Nanotechnology
	Volume	28	Issue	28	Pages	185202
	Keywords	A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
	Abstract	We compare classical versus quantum electron transport in recently investigated magnetic focusing devices (Bhandari et al 2016 Nano Lett. 16 1690) exposed to the perturbing potential of a scanning gate microscope (SGM). Using the Landauer-Buttiker formalism for a multi-terminal device, we calculate resistance maps that are obtained as the SGM tip is scanned over the sample. There are three unique regimes in which the scanning tip can operate (focusing, repelling, and mixed regime) which are investigated. Tip interacts mostly with electrons with cyclotron trajectories passing directly underneath it, leaving a trail of modified current density behind it. Other (indirect) trajectories become relevant when the tip is placed near the edges of the sample, and current is scattered between the tip and the edge. We point out that, in contrast to SGM experiments on gapped semiconductors, the STM tip can induce a pn junction in graphene, which improves contrast and resolution in SGM. We also discuss possible explanations for spatial asymmetry of experimentally measured resistance maps, and connect it with specific configurations of the measuring probes.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Bristol	Editor
	Language		Wos	000399273800001	Publication Date	2017-03-17
	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	7	Open Access
	Notes	; This work was supported by the Methusalem program of the Flemish government. ;			Approved	Most recent IF: 3.44
	Call Number	UA @ lucian @ c:irua:143639			Serial	4607
Permanent link to this record



	Author	Duflou, R.; Ciubotaru, F.; Vaysset, A.; Heyns, M.; Sorée, B.; Radu, I.P.; Adelmann, C.
	Title	Micromagnetic simulations of magnetoelastic spin wave excitation in scaled magnetic waveguides			Type	A1 Journal article
	Year	2017	Publication	Applied physics letters	Abbreviated Journal
	Volume	111	Issue	19	Pages	192411
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	We study the excitation of spin waves in scaled magnetic waveguides using the magnetoelastic effect. In uniformly magnetized systems, normal strains parallel or perpendicular to the magnetization direction do not lead to spin wave excitation since the magnetoelastic torque is zero. Using micromagnetic simulations, we show that the nonuniformity of the magnetization in submicron waveguides due to the effect of the demagnetizing field leads to the excitation of spin waves for oscillating normal strains both parallel and perpendicular to the magnetization. The excitation by biaxial normal in-plane strain was found to be much more efficient than that by uniaxial normal out-of-plane strain. For narrow waveguides with a width of 200 nm, the excitation efficiency of biaxial normal in-plane strain was comparable to that of shear strain. Published by AIP Publishing.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000414975500027	Publication Date	2017-11-10
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0003-6951; 1077-3118	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:152599			Serial	8247
Permanent link to this record



	Author	Volodin, A.; Van Haesendonck, C.; Leenaerts, O.; Partoens, B.; Peeters, F.M.
	Title	Stress dependence of the suspended graphene work function : vacuum Kelvin probe force microscopy and density functional theory			Type	A1 Journal article
	Year	2017	Publication	Applied physics letters	Abbreviated Journal	Appl Phys Lett
	Volume	110	Issue	19	Pages	193101
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	We report on work function measurements on graphene, which is exfoliated over a predefined array of wells in silicon oxide, by Kelvin probe force microscopy operating in a vacuum. The obtained graphene sealed microchambers can support large pressure differences, providing controllable stretching of the nearly impermeable graphene membranes. These measurements allow detecting variations of the work function induced by the mechanical stresses in the suspended graphene where the work function varies linearly with the strain and changes by 62 +/- 2 meV for 1 percent of strain. Our related ab initio calculations result in a work function variation that is a factor of 1.4 larger than the experimental value. The limited discrepancy between the theory and the experiment can be accounted for by a charge transfer from the unstrained to the strained graphene regions. Published by AIP Publishing.
	Address
	Corporate Author				Thesis
	Publisher	American Institute of Physics	Place of Publication	New York, N.Y.	Editor
	Language		Wos	000402319200036	Publication Date	2017-05-08
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0003-6951; 1077-3118	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.411	Times cited	8	Open Access
	Notes	; The authors wish to thank A. Klekachev (IMEC Leuven, Belgium) for the fabrication of the samples. This work was supported by the Science Foundation-Flanders (FWO, Belgium). The computational resources and services used in this work were provided by the VSC (Flemish Supercomputer Center), funded by the Hercules Foundation and the Flemish Government-Department EWI. The Hercules Foundation also funded the scanning probe microscopy equipment. ;			Approved	Most recent IF: 3.411
	Call Number	UA @ lucian @ c:irua:144279			Serial	4690
Permanent link to this record



	Author	Kleibert, A.; Balan, A.; Yanes, R.; Derlet, P.M.; Vaz, C.A.F.; Timm, M.; Fraile Rodríguez, A.; Béché, A.; Verbeeck, J.; Dhaka, R.S.; Radovic, M.; Nowak, U.; Nolting, F.
	Title	Direct observation of enhanced magnetism in individual size- and shape-selected 3d transition metal nanoparticles			Type	A1 Journal article
	Year	2017	Publication	Physical review B	Abbreviated Journal	Phys Rev B
	Volume	95	Issue	95	Pages	195404
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	Magnetic nanoparticles are critical building blocks for future technologies ranging from nanomedicine to spintronics. Many related applications require nanoparticles with tailored magnetic properties. However, despite significant efforts undertaken towards this goal, a broad and poorly understood dispersion of magnetic properties is reported, even within monodisperse samples of the canonical ferromagnetic 3d transition metals. We address this issue by investigating the magnetism of a large number of size- and shape-selected, individual nanoparticles of Fe, Co, and Ni using a unique set of complementary characterization techniques. At room temperature, only superparamagnetic behavior is observed in our experiments for all Ni nanoparticles within the investigated sizes, which range from 8 to 20 nm. However, Fe and Co nanoparticles can exist in two distinct magnetic states at any size in this range: (i) a superparamagnetic state, as expected from the bulk and surface anisotropies known for the respective materials and as observed for Ni, and (ii) a state with unexpected stable magnetization at room temperature. This striking state is assigned to significant modifications of the magnetic properties arising from metastable lattice defects in the core of the nanoparticles, as concluded by calculations and atomic structural characterization. Also related with the structural defects, we find that the magnetic state of Fe and Co nanoparticles can be tuned by thermal treatment enabling one to tailor their magnetic properties for applications. This paper demonstrates the importance of complementary single particle investigations for a better understanding of nanoparticle magnetism and for full exploration of their potential for applications.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000400665300002	Publication Date	2017-05-05
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2469-9950	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.836	Times cited	21	Open Access	OpenAccess
	Notes	We thank A. Weber, R. Schelldorfer, and J. Krbanjevic (Paul Scherrer Institut) for technical assistance. This paper was supported by the Swiss Nanoscience Institute, University of Basel. A.F.R. acknowledges support from the MICIIN “Ramón y Cajal” Programme. A.B. and J.V. acknowledge funding from the European Union under the European Research Council (ERC) Starting Grant No. 278510 VORTEX and under a contract for Integrated Infrastructure Initiative ESTEEM2 No. 312483. R.Y. and U.N. thank the Deutsche Forschungsgemeinschaft for financial support via Sonderforschungsbereich 1214. Part of this work was performed at the Surface/Interface: Microscopy (SIM) beamline of the Swiss Light Source, Paul Scherrer Institut, Villigen, Switzerland.			Approved	Most recent IF: 3.836
	Call Number	EMAT @ emat @ c:irua:143634UA @ admin @ c:irua:143634			Serial	4575
Permanent link to this record



	Author	de Sousa, G.O.; da Costa, D.R.; Chaves, A.; Farias, G.A.; Peeters, F.M.
	Title	Unusual quantum confined Stark effect and Aharonov-Bohm oscillations in semiconductor quantum rings with anisotropic effective masses			Type	A1 Journal article
	Year	2017	Publication	Physical review B	Abbreviated Journal	Phys Rev B
	Volume	95	Issue	95	Pages	205414
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	The effects of external electric and magnetic fields on the energy spectrum of quantum rings made out of a bidimensional semiconductor material with anisotropic band structures are investigated within the effective-mass model. The interplay between the effective-mass anisotropy and the radial confinement leads to wave functions that are strongly localized at two diametrically opposite regions where the kinetic energy is lowest due to the highest effective mass. We show that this quantum phenomenon has clear consequences on the behavior of the energy states in the presence of applied in-plane electric fields and out-of-plane magnetic fields. In the former, the quantum confined Stark effect is observed with either linear or quadratic shifts, depending on the direction of the applied field. As for the latter, the usual Aharonov-Bohm oscillations are not observed for a circularly symmetric confining potential, however they can be reinstated if an elliptic ring with an appropriate aspect ratio is chosen.
	Address
	Corporate Author				Thesis
	Publisher	American Physical Society	Place of Publication	New York, N.Y	Editor
	Language		Wos	000401230600007	Publication Date	2017-05-12
	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	19	Open Access
	Notes	; This work was financially supported by CNPq under the PRONEX/FUNCAP grants, CAPES Foundation, the Flemish Science Foundation (FWO-Vl), and the Brazilian Program Science Without Borders (CsF). ;			Approved	Most recent IF: 3.836
	Call Number	UA @ lucian @ c:irua:143746			Serial	4610
Permanent link to this record



	Author	Li, L.L.; Moldovan, D.; Vasilopoulos, P.; Peeters, F.M.
	Title	Aharonov-Bohm oscillations in phosphorene quantum rings			Type	A1 Journal article
	Year	2017	Publication	Physical review B	Abbreviated Journal	Phys Rev B
	Volume	95	Issue	20	Pages	205426
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	The Aharonov-Bohm (AB) effect in square phosphorene quantum rings, with armchair and zigzag edges, is investigated using the tight-binding method. The energy spectra and wave functions of such rings, obtained as a function of the magnetic flux Phi threading the ring, are strongly influenced by the ringwidthW, an in-plane electric field E-p, and a side-gating potential V-g. Compared to a square dot, the ring shows an enhanced confinement due to its inner edges and an interedge coupling along the zigzag direction, both of which strongly affect the energy spectrum and the wave functions. The energy spectrum that is gapped consists of a regular part, of conduction (valence) band states, that shows the usual AB oscillations in the higher-(lower-) energy region, and of edge states, in the gap, that exhibit no AB oscillations. As the width W decreases, the AB oscillations become more distinct and regular and their period is close to Phi(0)/2, where the flux quantum Phi(0) = h/e is the period of an ideal circular ring (W -> 0). Both the electric field E-p and the side-gating potential V-g reduce the amplitude of the AB oscillations. The amplitude can be effectively tuned by E-p or V-g and exhibits an anisotropic behavior for different field directions or side-gating configurations.
	Address
	Corporate Author				Thesis
	Publisher	American Physical Society	Place of Publication	New York, N.Y	Editor
	Language		Wos	000402003700010	Publication Date	2017-05-23
	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	16	Open Access
	Notes	; This work was financially supported by the Chinese Academy of Sciences, the Flemish Science Foundation (FWO-V1), and by the Canadian NSERC Grant No. OGP0121756 (P.V.). ;			Approved	Most recent IF: 3.836
	Call Number	UA @ lucian @ c:irua:144267			Serial	4638
Permanent link to this record



	Author	Stosic, D.; Ludermir, T.B.; Milošević, M.V.
	Title	Pinning of magnetic skyrmions in a monolayer Co film on Pt(111) : Theoretical characterization and exemplified utilization			Type	A1 Journal article
	Year	2017	Publication	Physical review B	Abbreviated Journal	Phys Rev B
	Volume	96	Issue	21	Pages	214403
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	<script type='text/javascript'>document.write(unpmarked('Magnetic skyrmions are nanoscale windings of the spin structure that can be observed in chiral magnets and hold promise for potential applications in storing or processing information. Pinning due to ever-present material imperfections crucially affects the mobility of skyrmions. Therefore, a proper understanding of how magnetic skyrmions pin to defects is necessary for the development and performance of spintronic devices. Here we present a fundamental analysis on the interactions of single skyrmions with atomic defects of distinctly different origins, in a Co monolayer on Pt, based on minimum-energy paths considerations and atomic-spin simulations. We first report the preferred pinning loci of the skyrmion as a function of its nominal size and the type of defect being considered, to further reveal the manipulation and \u0022breathing\u0022 of skyrmion core in the vicinity of a defect. We also show the behavior of skyrmions in the presence of an extended defect of particular geometry, that can lead to ratcheted skyrmion motion or a facilitated guidance on a defect \u0022trail.\u0022 We close the study with reflections on the expected thermal stability of the skyrmion against collapse on itself for a given nature of the defect, and discuss the applications where control of skyrmions by defects is of particular interest.'));
	Address
	Corporate Author				Thesis
	Publisher	American Physical Society	Place of Publication	New York, N.Y	Editor
	Language		Wos	000416846900002	Publication Date	2017-12-01
	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	52	Open Access
	Notes	; This work was supported by the Research Foundation, Flanders (FWO-Vlaanderen) and Brazilian agency CNPq (Grants No. 442668/2014-7 and No. 140840/2016-8). ;			Approved	Most recent IF: 3.836
	Call Number	UA @ lucian @ c:irua:147684			Serial	4890
Permanent link to this record



	Author	Stosic, D.; Mulkers, J.; Van Waeyenberge, B.; Ludermir, T.B.; Milošević, M.V.
	Title	Paths to collapse for isolated skyrmions in few-monolayer ferromagnetic films			Type	A1 Journal article
	Year	2017	Publication	Physical review B	Abbreviated Journal	Phys Rev B
	Volume	95	Issue	21	Pages	214418
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	Magnetic skyrmions are topological spin configurations in materials with chiral Dzyaloshinskii-Moriya interaction (DMI), that are potentially useful for storing or processing information. To date, DMI has been found in few bulk materials, but can also be induced in atomically thin magnetic films in contact with surfaces with large spin-orbit interactions. Recent experiments have reported that isolated magnetic skyrmions can be stabilized even near room temperature in few-atom-thick magnetic layers sandwiched between materials that provide asymmetric spin-orbit coupling. Here we present the minimum-energy path analysis of three distinct mechanisms for the skyrmion collapse, based on ab initio input and the performed atomic-spin simulations. We focus on the stability of a skyrmion in three atomic layers of Co, either epitaxial on the Pt(111) surface or within a hybrid multilayer where DMI nontrivially varies per monolayer due to competition between different symmetry breaking from two sides of the Co film. In laterally finite systems, their constrained geometry causes poor thermal stability of the skyrmion toward collapse at the boundary, which we show to be resolved by designing the high-DMI structure within an extended film with lower or no DMI.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000404015500001	Publication Date	2017-06-23
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2469-9950	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.836	Times cited	48	Open Access
	Notes	This work was supported by the Research Foundation, Flanders (FWO-Vlaanderen) and Brazilian agency CNPq (Grants No. 442668/2014-7 and No. 140840/2016-8).			Approved	Most recent IF: 3.836
	Call Number	CMT @ cmt @c:irua:144865			Serial	4704
Permanent link to this record