Home | << 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 >> |
![]() |
Records | |||||
---|---|---|---|---|---|
Author | Peeters, F.M.; Vasilopoulos, P. | ||||
Title | Electrical and thermal properties of a two-dimensional electron gas in a one-dimensional periodic potential | Type | A1 Journal article | ||
Year | 1992 | Publication | Physical review: B | Abbreviated Journal | Phys Rev B |
Volume | 46 | Issue | Pages | 4667-4680 | |
Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
Abstract | |||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher ![]() |
Place of Publication | Editor | |||
Language | Wos | A1992JK72500032 | Publication Date | 2002-07-27 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0163-1829 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 3.736 | Times cited | 148 | Open Access | |
Notes | Approved | INSTRUMENTS & INSTRUMENTATION 31/56 Q3 # NUCLEAR SCIENCE & TECHNOLOGY 9/32 Q2 # PHYSICS, PARTICLES & FIELDS 24/28 Q4 # SPECTROSCOPY 28/43 Q3 # | |||
Call Number | UA @ lucian @ c:irua:2998 | Serial | 890 | ||
Permanent link to this record | |||||
Author | Deo, P.S.; Schweigert, V.A.; Peeters, F.M. | ||||
Title | Hysteresis in mesoscopic superconducting disks: the Bean-Livingston barrier | Type | A1 Journal article | ||
Year | 1999 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal | Phys Rev B |
Volume | 59 | Issue | Pages | 6039-6042 | |
Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
Abstract | |||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher ![]() |
Place of Publication | Lancaster, Pa | Editor | ||
Language | Wos | 000079254300016 | Publication Date | 2002-07-27 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0163-1829;1095-3795; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 3.836 | Times cited | 59 | Open Access | |
Notes | Approved | Most recent IF: 3.836; 1999 IF: NA | |||
Call Number | UA @ lucian @ c:irua:24156 | Serial | 1545 | ||
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 | |||||
Author | Tan, H.; Egoavil, R.; Béché, A.; Martinez, G.T.; Van Aert, S.; Verbeeck, J.; Van Tendeloo, G.; Rotella, H.; Boullay, P.; Pautrat, A.; Prellier, W. | ||||
Title | Mapping electronic reconstruction at the metal-insulator interface in LaVO3/SrVO3 heterostructures | Type | A1 Journal article | ||
Year | 2013 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal | Phys Rev B |
Volume | 88 | Issue | 15 | Pages | 155123-155126 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | A (LaVO3)6/(SrVO3)(3) superlattice is studied with a combination of sub-A resolved scanning transmission electron microscopy and monochromated electron energy-loss spectroscopy. The V oxidation state is mapped with atomic spatial resolution enabling us to investigate electronic reconstruction at the LaVO3/SrVO3 interfaces. Surprisingly, asymmetric charge distribution is found at adjacent chemically symmetric interfaces. The local structure is proposed and simulated with a double channeling calculation which agrees qualitatively with our experiment. We demonstrate that local strain asymmetry is the likely cause of the electronic asymmetry of the interfaces. The electronic reconstruction at the interfaces extends much further than the chemical composition, varying from 0.5 to 1.2 nm. This distance corresponds to the length of charge transfer previously found in the (LaVO3)./(SrVO3). metal/insulating and the (LaAlO3)./(SrTiO3). insulating/insulating interfaces. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher ![]() |
Place of Publication | Editor | |||
Language | Wos | 000326087100003 | Publication Date | 2013-10-21 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 1098-0121;1550-235X; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 3.836 | Times cited | 15 | Open Access | |
Notes | Hercules; 246791 COUNTATOMS; 278510 VORTEX; 246102 IFOX; 312483 ESTEEM2; FWO; GOA XANES meets ELNES; esteem2jra3 ECASJO; | Approved | Most recent IF: 3.836; 2013 IF: 3.664 | ||
Call Number | UA @ lucian @ c:irua:112733UA @ admin @ c:irua:112733 | Serial | 1944 | ||
Permanent link to this record | |||||
Author | Schattschneider, P.; Schaffer, B.; Ennen, I.; Verbeeck, J. | ||||
Title | Mapping spin-polarized transitions with atomic resolution | Type | A1 Journal article | ||
Year | 2012 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal | Phys Rev B |
Volume | 85 | Issue | 13 | Pages | 134422-134422,8 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | The coupling of angstrom-sized electron probes with spin-polarized electronic transitions shows that the inelastically scattered probe electron is in a mixed state containing electron vortices with nonzero orbital angular momentum. These electrons create an asymmetric intensity distribution in energy filtered diffraction patterns, giving access to maps of the magnetic moments with atomic resolution. A feasibility experiment shows evidence of the predicted effect. Potential applications are column-by-column maps of magnetic ordering, and the creation of angstrom-sized free electrons with orbital angular momentum by inelastic scattering in a thin ferromagnetic foil. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher ![]() |
Place of Publication | Editor | |||
Language | Wos | 000302608100004 | Publication Date | 2012-04-11 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 1098-0121;1550-235X; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 3.836 | Times cited | 41 | Open Access | |
Notes | The authors thank A. Bleloch, S. Loffler, and P. Nellist for fruitful discussions and suggestions. P.S. acknowledges financial support from the Austrian Science Fund, Project No. I543-N20. The support of the EPSRC for the SuperSTEM facility is gratefully acknowledged. J.V. acknowledges support from the European Research Council under the 7th Framework Program (FP7), ERC Grant No. 246791-COUNTATOMS and ERC Starting Grant No. 278510-VORTEX. ECASJO_; | Approved | Most recent IF: 3.836; 2012 IF: 3.767 | ||
Call Number | UA @ lucian @ c:irua:97390UA @ admin @ c:irua:97390 | Serial | 1945 | ||
Permanent link to this record | |||||
Author | Zha, G.-Q.; Covaci, L.; Peeters, F.M.; Zhou, S.-P. | ||||
Title | Mixed pairing symmetries and flux-induced spin current in mesoscopic superconducting loops with spin correlations | Type | A1 Journal article | ||
Year | 2015 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal | Phys Rev B |
Volume | 91 | Issue | 91 | Pages | 214504 |
Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
Abstract | We numerically investigate the mixed pairing symmetries inmesoscopic superconducting loops in the presence of spin correlations by solving the Bogoliubov-de Gennes equations self-consistently. The spatial variations of the superconducting order parameters and the spontaneous magnetization are determined by the band structure. When the threaded magnetic flux turns on, the charge and spin currents both emerge and depict periodic evolution. In the case of a mesoscopic loop with dominant triplet p(x) +/- ip(y)-wave symmetry, a slight change of the chemical potential may lead to novel flux-dependent evolution patterns of the ground-state energy and the magnetization. The spin-polarized currents show pronounced quantum oscillations with fractional periods due to the appearance of energy jumps in flux, accompanied with a steplike feature of the enhanced spin current. Particularly, at some appropriate flux, the peaks of the zero-energy local density of states clearly indicate the occurrence of the odd-frequency pairing. In the case of a superconducting loop with dominant singlet d(x2-y2)-wave symmetry, the spatial profiles of the zero-energy local density of states and the magnetization show spin-dependent features on different sample diagonals. Moreover, the evolution of the flux-induced spin current always exhibits an hc/e periodicity. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher ![]() |
Place of Publication | Editor | |||
Language | Wos | 000355647100003 | Publication Date | 2015-06-05 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 1098-0121;1550-235X; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 3.836 | Times cited | 15 | Open Access | |
Notes | ; This work was supported by the National Natural Science Foundation of China under Grants No. 61371020 and No. 61271163, by the Visiting Scholar Program of Shanghai Municipal Education Commission, and by the Flemish Science Foundation (FWO-Vl). ; | Approved | Most recent IF: 3.836; 2015 IF: 3.736 | ||
Call Number | c:irua:126433 | Serial | 2089 | ||
Permanent link to this record | |||||
Author | Zhang, L.; Turner, S.; Brosens, F.; Verbeeck, J. | ||||
Title | Model-based determination of dielectric function by STEM low-loss EELS | Type | A1 Journal article | ||
Year | 2010 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal | Phys Rev B |
Volume | 81 | Issue | 3 | Pages | 035102 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Theory of quantum systems and complex systems | ||||
Abstract | Dielectric properties of materials are crucial in describing the electromagnetic response of materials. As devices are becoming considerably smaller than the optical wavelength, the conventional measuring methods based on optical response are limited by their spatial resolution. Electron energy loss spectroscopy performed in a scanning transmission electron microscope is a good alternative to obtain the dielectric properties with excellent spatial resolution. Due to the overlap of diffraction discs in scanning transmission electron microscopy, it is difficult to apply conventional experimental settings to suppress retardation losses. In this contribution, a relativistic dielectric model for the loss function is presented which is used in a model based optimization scheme to estimate the complex dielectric function of a material. The method is applied to experiments on bulk diamond and SrTiO3 and shows a good agreement with optical reference data when retardation effects are included. Application of this technique to nanoparticles is possible but several theoretical assumptions made in the model of the loss function are violated and interpretation becomes problematic. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher ![]() |
Place of Publication | Lancaster, Pa | Editor | ||
Language | Wos | 000274002300027 | Publication Date | 2010-01-08 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 1098-0121;1550-235X; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 3.836 | Times cited | 9 | Open Access | |
Notes | Esteem – 026019; Fwo | Approved | Most recent IF: 3.836; 2010 IF: 3.774 | ||
Call Number | UA @ lucian @ c:irua:81258UA @ admin @ c:irua:81258 | Serial | 2098 | ||
Permanent link to this record | |||||
Author | Muñoz, W.A.; Covaci, L.; Peeters, F.M. | ||||
Title | Superconducting current and proximity effect in ABA and ABC multilayer graphene Josephson junctions | Type | A1 Journal article | ||
Year | 2013 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal | Phys Rev B |
Volume | 88 | Issue | 88 | Pages | 214502 |
Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
Abstract | Using a numerical tight-binding approach based on the Chebyshev–Bogoliubov–de Gennes method we describe Josephson junctions made of multilayer graphene contacted by top superconducting gates. Both Bernal (ABA) and rhombohedral (ABC) stacking are considered and we find that the type of stacking has a strong effect on the proximity effect and the supercurrent flow. For both cases the pair amplitude shows a polarization between dimer and nondimer atoms, being more pronounced for rhombohedral stacking. Even though the proximity effect in nondimer sites is enhanced when compared to single-layer graphene, we find that the supercurrent is suppressed. The spatial distribution of the supercurrent shows that for Bernal stacking the current flows only in the topmost layers while for rhombohedral stacking the current flows throughout the whole structure. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher ![]() |
Place of Publication | Editor | |||
Language | Wos | 000328569900004 | Publication Date | 2013-12-02 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 1098-0121;1550-235X; | 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 supported by the Flemish Science Foundation (FWO-Vl) and the Methusalem funding of the Flemish Government | Approved | Most recent IF: 3.836; 2013 IF: 3.664 | ||
Call Number | CMT @ cmt @ c:irua:128896 | Serial | 3962 | ||
Permanent link to this record | |||||
Author | Muñoz, W.A.; Covaci, L.; Peeters, F.M. | ||||
Title | Disordered graphene Josephson junctions | Type | A1 Journal article | ||
Year | 2015 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal | Phys Rev B |
Volume | 91 | Issue | 91 | Pages | 054506 |
Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
Abstract | A tight-binding approach based on the Chebyshev-Bogoliubov-de Gennes method is used to describe disordered single-layer graphene Josephson junctions. Scattering by vacancies, ripples, or charged impurities is included. We compute the Josephson current and investigate the nature of multiple Andreev reflections, which induce bound states appearing as peaks in the density of states for energies below the superconducting gap. In the presence of single-atom vacancies, we observe a strong suppression of the supercurrent, which is a consequence of strong intervalley scattering. Although lattice deformations should not induce intervalley scattering, we find that the supercurrent is still suppressed, which is due to the presence of pseudomagnetic barriers. For charged impurities, we consider two cases depending on whether the average doping is zero, i.e., existence of electron-hole puddles, or finite. In both cases, short-range impurities strongly affect the supercurrent, similar to the vacancies scenario. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher ![]() |
Place of Publication | Editor | |||
Language | Wos | 000349436500001 | Publication Date | 2015-02-06 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 1098-0121;1550-235X; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 3.836 | Times cited | 7 | Open Access | |
Notes | This work was supported by the Flemish Science Foundation (FWO-Vlaanderen) and the Methusalem funding of the Flemish Government. | Approved | Most recent IF: 3.836; 2015 IF: 3.736 | ||
Call Number | c:irua:129192 | Serial | 3961 | ||
Permanent link to this record | |||||
Author | Van Aert, S.; de Backer, A.; Martinez, G.T.; Goris, B.; Bals, S.; Van Tendeloo, G.; Rosenauer, A. | ||||
Title | Procedure to count atoms with trustworthy single-atom sensitivity | Type | A1 Journal article | ||
Year | 2013 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal | Phys Rev B |
Volume | 87 | Issue | 6 | Pages | 064107-6 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | We report a method to reliably count the number of atoms from high-angle annular dark field scanning transmission electron microscopy images. A model-based analysis of the experimental images is used to measure scattering cross sections at the atomic level. The high sensitivity of these measurements in combination with a thorough statistical analysis enables us to count atoms with single-atom sensitivity. The validity of the results is confirmed by means of detailed image simulations. We will show that the method can be applied to nanocrystals of arbitrary shape, size, and atom type without the need for a priori knowledge about the atomic structure. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher ![]() |
Place of Publication | Editor | |||
Language | Wos | 000315144700006 | Publication Date | 2013-02-20 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 1098-0121;1550-235X; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 3.836 | Times cited | 106 | Open Access | |
Notes | FWO; 262348 ESMI; 312483 ESTEEM2;246791 COUNTATOMS; Hercules 3; esteem2_jra2 | Approved | Most recent IF: 3.836; 2013 IF: 3.664 | ||
Call Number | UA @ lucian @ c:irua:105674 | Serial | 2718 | ||
Permanent link to this record | |||||
Author | Wen, X.; Peeters, F.M.; Devreese, J.T. | ||||
Title | Streaming-to-accumulation transition in a two-dimensional electron system in a polar semiconductor | Type | A1 Journal article | ||
Year | 1992 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal | Phys Rev B |
Volume | 46 | Issue | Pages | 7571-7580 | |
Keywords | A1 Journal article; Condensed Matter Theory (CMT); Theory of quantum systems and complex systems | ||||
Abstract | |||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher ![]() |
Place of Publication | Editor | |||
Language | Wos | A1992JQ37800028 | Publication Date | 2002-07-27 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0163-1829 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 3.736 | Times cited | 13 | Open Access | |
Notes | Approved | PHYSICS, APPLIED 28/145 Q1 # | |||
Call Number | UA @ lucian @ c:irua:2913 | Serial | 3175 | ||
Permanent link to this record | |||||
Author | Verbist, G.; Smondyrev, M.A.; Peeters, F.M.; Devreese, J.T. | ||||
Title | Strong-coupling analysis of large bipolarons in two and three dimensions | Type | A1 Journal article | ||
Year | 1992 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal | Phys Rev B |
Volume | 45 | Issue | Pages | 5262-5269 | |
Keywords | A1 Journal article; Condensed Matter Theory (CMT); Theory of quantum systems and complex systems | ||||
Abstract | |||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher ![]() |
Place of Publication | Editor | |||
Language | Wos | A1992HJ68900016 | Publication Date | 2002-07-27 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0163-1829 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 3.736 | Times cited | 68 | Open Access | |
Notes | Approved | PHYSICS, APPLIED 28/145 Q1 # | |||
Call Number | UA @ lucian @ c:irua:2891 | Serial | 3179 | ||
Permanent link to this record | |||||
Author | Potapov, P.L.; Kulkova, S.E.; Schryvers, D.; Verbeeck, J. | ||||
Title | Structural and chemical effects on EELS L3,2 ionization edges in Ni-based intermetallic compounds | Type | A1 Journal article | ||
Year | 2001 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal | Phys Rev B |
Volume | 64 | Issue | Pages | 184110,1-9 | |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | |||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher ![]() |
Place of Publication | Lancaster, Pa | Editor | ||
Language | Wos | 000172239400038 | Publication Date | 2002-07-27 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 1098-0121;1550-235X; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 3.836 | Times cited | 44 | Open Access | |
Notes | Approved | Most recent IF: 3.836; 2001 IF: NA | |||
Call Number | UA @ lucian @ c:irua:48393 | Serial | 3192 | ||
Permanent link to this record | |||||
Author | Verbeeck, J.; Lebedev, O.I.; Van Tendeloo, G.; Mercey, B. | ||||
Title | SrTiO3(100)/(LaMnO3)m(SrMnO3)n layered heterostructures: a combined EELS and TEM study | Type | A1 Journal article | ||
Year | 2002 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal | Phys Rev B |
Volume | 66 | Issue | 18 | Pages | 184426 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | Epitaxially grown heterostructures consisting of alternating layers of LaMnO(3) (LMO, 9 or 15 unit cells) and SrMnO(3) (SMO, 4 or 6 unit cells) on a SrTiO(3)(100) (STO(100)) substrate have been studied by a combination of high resolution transmission electron microscopy (HRTEM), electron diffraction, quantitative electron energy loss spectroscopy (EELS) with model fitting, energy filtered TEM (EFTEM) and imaging spectroscopy on an atomic scale. The combination of these techniques is necessary for the structural, chemical, and electronic characterization of these heterostructures. A model is proposed containing chemically and structurally sharp interfaces. The SrMnO(3) layers are stabilized in a Pm3m structure between two LMO layers. Tensile stress causes oxygen deficiency in the SMO layers increasing the number of 3d electrons on the Mn sites to resemble the Mn(3+) sites in LMO. The energy loss near edge structure (ELNES) of O and Mn is compared for both LMO and SMO layers and shows that the Mn-O bonds have a partially covalent character. The absence of a strong valency effect in the Mn ELNES is due to the oxygen vacancies in SMO. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher ![]() |
Place of Publication | Lancaster, Pa | Editor | ||
Language | Wos | 000179633100062 | Publication Date | 2002-11-27 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0163-1829;1095-3795; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 3.836 | Times cited | 32 | Open Access | |
Notes | Approved | Most recent IF: 3.836; 2002 IF: NA | |||
Call Number | UA @ lucian @ c:irua:54741 | Serial | 3563 | ||
Permanent link to this record | |||||
Author | Zhang, L.-F.; Covaci, L.; Peeters, F.M. | ||||
Title | Tomasch effect in nanoscale superconductors | Type | A1 Journal article | ||
Year | 2015 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal | Phys Rev B |
Volume | 91 | Issue | 91 | Pages | 024508 |
Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
Abstract | The Tomasch effect (TE) is due to quasiparticle interference (QPI) as induced by a nonuniform superconducting order parameter, which results in oscillations in the density of states (DOS) at energies above the superconducting gap. Quantum confinement in nanoscale superconductors leads to an inhomogenerous distribution of the Cooperpair condensate, which, as we found, triggers the manifestation of a new TE. We investigate the electronic structure of nanoscale superconductors by solving the Bogoliubov-de Gennes (BdG) equations self-consistently and describe the TE determined by two types of processes, involving two-or three-subband QPIs. Both types of QPIs result in additional BCS-like Bogoliubov-quasiparticles and BCS-like energy gaps leading to oscillations in the DOS and modulated wave patterns in the local density of states. These effects are strongly related to the symmetries of the system. A reduced 4 x 4 inter-subband BdG Hamiltonian is established in order to describe analytically the TE of two-subband QPIs. Our study is relevant to nanoscale superconductors, either nanowires or thin films, Bose-Einsten condensates, and confined systems such as two-dimensional electron gas interface superconductivity. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher ![]() |
Place of Publication | Lancaster, Pa | Editor | ||
Language | Wos | 000348473700003 | Publication Date | 2015-01-16 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 1098-0121;1550-235X; | 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 Flemish Science Foundation (FWO-Vlaanderen) and the Methusalem funding of the Flemish Government. ; | Approved | Most recent IF: 3.836; 2015 IF: 3.736 | ||
Call Number | c:irua:123864 | Serial | 3670 | ||
Permanent link to this record | |||||
Author | Juchtmans, R.; Béché, A.; Abakumov, A.; Batuk, M.; Verbeeck, J. | ||||
Title | Using electron vortex beams to determine chirality of crystals in transmission electron microscopy | Type | A1 Journal article | ||
Year | 2015 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal | Phys Rev B |
Volume | 91 | Issue | 91 | Pages | 094112 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | We investigate electron vortex beams elastically scattered on chiral crystals. After deriving a general expression for the scattering amplitude of a vortex electron, we study its diffraction on point scatterers arranged on a helix. We derive a relation between the handedness of the helix and the topological charge of the electron vortex on one hand and the symmetry of the higher-order Laue zones in the diffraction pattern on the other for kinematically and dynamically scattered electrons. We then extend this to atoms arranged on a helix as found in crystals which belong to chiral space groups and propose a method to determine the handedness of such crystals by looking at the symmetry of the diffraction pattern. In contrast to alternative methods, our technique does not require multiple scattering, which makes it possible to also investigate extremely thin samples in which multiple scattering is suppressed. In order to verify the model, elastic scattering simulations are performed, and an experimental demonstration on Mn2Sb2O7 is given in which we find the sample to belong to the right-handed variant of its enantiomorphic pair. This demonstrates the usefulness of electron vortex beams to reveal the chirality of crystals in a transmission electron microscope and provides the required theoretical basis for further developments in this field. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher ![]() |
Place of Publication | Editor | |||
Language | Wos | 000352017000002 | Publication Date | 2015-03-27 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 1098-0121;1550-235X; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 3.836 | Times cited | 54 | Open Access | |
Notes | Fwo; 312483 Esteem2; 278510 Vortex; esteem2jra1; esteem2jra2 ECASJO_; | Approved | Most recent IF: 3.836; 2015 IF: 3.736 | ||
Call Number | c:irua:125512 c:irua:125512 | Serial | 3825 | ||
Permanent link to this record | |||||
Author | Zhang, L.-F.; Covaci, L.; Milošević, M.V.; Berdiyorov, G.R.; Peeters, F.M. | ||||
Title | Vortex states in nanoscale superconducting squares : the influence of quantum confinement | Type | A1 Journal article | ||
Year | 2013 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal | Phys Rev B |
Volume | 88 | Issue | 14 | Pages | 144501 |
Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
Abstract | Bogoliubov-de Gennes theory is used to investigate the effect of the size of a superconducting square on the vortex states in the quantum confinement regime. When the superconducting coherence length is comparable to the Fermi wavelength, the shape resonances of the superconducting order parameter have strong influence on the vortex configuration. Several unconventional vortex states, including asymmetric ones, giant-multivortex combinations, and states comprising giant antivortices, were found as ground states and their stability was found to be very sensitive on the value of k(F)xi(0), the size of the sample W, and the magnetic flux Phi. By increasing the temperature and/or enlarging the size of the sample, quantum confinement is suppressed and the conventional mesoscopic vortex states as predicted by the Ginzburg-Laudau (GL) theory are recovered. However, contrary to the GL results we found that the states containing symmetry-induced vortex-antivortex pairs are stable over the whole temperature range. It turns out that the inhomogeneous order parameter induced by quantum confinement favors vortex-antivortex molecules, as well as giant vortices with a rich structure in the vortex core-unattainable in the GL domain. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher ![]() |
Place of Publication | Editor | |||
Language | Wos | 000325498300004 | Publication Date | 2013-10-09 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 1098-0121;1550-235X; | 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 supported by the Flemish Science Foundation (FWO-Vlaanderen) and Methusalem Funding of the Flemish government. ; | Approved | Most recent IF: 3.836; 2013 IF: 3.664 | ||
Call Number | UA @ lucian @ c:irua:111145 | Serial | 3891 | ||
Permanent link to this record | |||||
Author | Callewaert, V.; Saniz, R.; Barbiellini, B.; Bansil, A.; Partoens, B. | ||||
Title | Application of the weighted-density approximation to the accurate description of electron-positron correlation effects in materials | Type | A1 Journal article | ||
Year | 2017 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
Volume | 96 | Issue | 8 | Pages | 085135 |
Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
Abstract | We discuss positron-annihilation lifetimes for a set of illustrative bulk materials within the framework of the weighted-density approximation (WDA). The WDA can correctly describe electron-positron correlations in strongly inhomogeneous systems, such as surfaces, where the applicability of (semi-)local approximations is limited. We analyze the WDA in detail and show that the electrons which cannot screen external charges efficiently, such as the core electrons, cannot be treated accurately via the pair correlation of the homogeneous electron gas. We discuss how this problem can be addressed by reducing the screening in the homogeneous electron gas by adding terms depending on the gradient of the electron density. Further improvements are obtained when core electrons are treated within the LDA and the valence electron using the WDA. Finally, we discuss a semiempirical WDA-based approach in which a sum rule is imposed to reproduce the experimental lifetimes. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher ![]() |
Place of Publication | Editor | |||
Language | Wos | 000408342600003 | Publication Date | 2017-08-24 | |
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 | 6 | Open Access | |
Notes | Fonds Wetenschappelijk Onderzoek, G. 0224.14N ; U.S. Department of Energy, DE-FG02-07ER46352 DE-AC02-05CH11231 DE-SC0012575 ; | Approved | Most recent IF: 3.836 | ||
Call Number | CMT @ cmt @c:irua:145703 | Serial | 4703 | ||
Permanent link to this record | |||||
Author | Adami, O.-A.; Jelić, Ž.L.; Xue, C.; Abdel-Hafiez, M.; Hackens, B.; Moshchalkov, V.V.; Milošević, M.V.; Van de Vondel, J.; Silhanek, A.V. | ||||
Title | Onset, evolution, and magnetic braking of vortex lattice instabilities in nanostructured superconducting films | Type | A1 Journal article | ||
Year | 2015 | Publication | Physical review: B: condensed matter and materials physics | Abbreviated Journal | Phys Rev B |
Volume | 92 | Issue | 92 | Pages | 134506 |
Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
Abstract | In 1976, Larkin and Ovchinnikov [Zh. Eksp. Teor. Fiz. 68, 1915 (1975) [Sov. Phys.–JETP 41, 960 (1976)]] predicted that vortex matter in superconductors driven by an electrical current can undergo an abrupt dynamic transition from a flux-flow regime to a more dissipative state at sufficiently high vortex velocities. Typically, this transition manifests itself as a large voltage jump at a particular current density, so-called instability current density J∗, which is smaller than the depairing current. By tuning the effective pinning strength in Al films, using an artificial periodic pinning array of triangular holes, we show that a unique and well-defined instability current density exists if the pinning is strong, whereas a series of multiple voltage transitions appear in the relatively weaker pinning regime. This behavior is consistent with time-dependent Ginzburg-Landau simulations, where the multiple-step transition can be unambiguously attributed to the progressive development of vortex chains and subsequently phase-slip lines. In addition, we explore experimentally the magnetic braking effects, caused by a thick Cu layer deposited on top of the superconductor, on the instabilities and the vortex ratchet effect. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher ![]() |
Place of Publication | Editor | |||
Language | Wos | 000362433200003 | Publication Date | 2015-10-08 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 1098-0121 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 3.836 | Times cited | 21 | Open Access | |
Notes | ACKNOWLEDGMENTS: This work was partially supported by the Fonds de la Recherche Scientifique-FNRS, the Methusalem Funding of the Flemish Government, the Research Foundation-Flanders (FWO), and COST Action MP1201. The work of A.V.S. and Z.L.J. is partially supported by “Mandat d’Impulsion Scientifique” MIS F.4527.13 of the F.R.S.-FNRS. B.H. is an associate researcher of the Fonds de la Recherche Scientifique- FNRS. The authors thank J. Cuppens for the data analysis at the early stage of this work, R. Delamare for his valuable help during the fabrication of the samples, and G. Grimaldi for helpful discussions. | Approved | Most recent IF: 3.836; 2015 IF: 3.736 | ||
Call Number | c:irua:128747 | Serial | 3981 | ||
Permanent link to this record | |||||
Author | Aierken, Y.; Leenaerts, O.; Peeters, F.M. | ||||
Title | Defect-induced faceted blue phosphorene nanotubes | Type | A1 Journal article | ||
Year | 2015 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal | Phys Rev B |
Volume | 92 | Issue | 92 | Pages | 104104 |
Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
Abstract | The properties of a new class of phosphorene nanotubes (PNT) are investigated by performing first-principles calculations. We demonstrate that it is advantageous to use blue phosphorene in order to make small nanotubes and propose a way to create low-energy PNTs by the inclusion of defect lines. Five different types of defect lines are investigated and incorporated in various combinations. The resulting defect-induced faceted PNTs have negligible bending stresses which leads to a reduction in the formation energy with respect to round PNTs. Our armchair faceted PNTs have similar formation energies than the recently proposed multiphase faceted PNTs, but they have a larger variety of possible structures. Our zigzag faceted PNTs have lower formation energies than round tubes and multiphase faceted nanotubes. The electronic properties of the defect-induced faceted PNTs are determined by the defect lines which control the band gap and the shape of the electronic states at the band edges. These band gaps increase with the radius of the nanotubes and converge to those of isolated defect lines. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher ![]() |
Place of Publication | Editor | |||
Language | Wos | 000361037200006 | Publication Date | 2015-09-12 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 1098-0121 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 3.836 | Times cited | 24 | Open Access | |
Notes | This work was supported by the Fonds Wetenschappelijk Onderzoek (FWO-Vl). The computational resources and ser- vices 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: 3.836; 2015 IF: 3.736 | ||
Call Number | c:irua:127837 | Serial | 4033 | ||
Permanent link to this record | |||||
Author | Aierken, Y.; Çakır, D.; Sevik, C.; Peeters, F.M. | ||||
Title | Thermal properties of black and blue phosphorenes from a first-principles quasiharmonic approach | Type | A1 Journal article | ||
Year | 2015 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal | Phys Rev B |
Volume | 92 | Issue | 92 | Pages | 081408 |
Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
Abstract | Different allotropes of phosphorene are possible of which black and blue phosphorus are the most stable. While blue phosphorus has isotropic properties, black phosphorus is strongly anisotropic in its electronic and optical properties due to its anisotropic crystal structure. In this work, we systematically investigated the lattice thermal properties of black and blue phosphorene by using first-principles calculations based on the quasiharmonic approximation approach. Similar to the optoelectronic and electronic properties, we predict that black phosphorene has highly anisotropic thermal properties, in contrast to the blue phase. The linear thermal expansion coefficients along the zigzag and armchair direction differ up to 20% in black phosphorene. The armchair direction of black phosphorene is more expandable as compared to the zigzag direction and the biaxial expansion of blue phosphorene under finite temperature. Our comparative analysis reveals that the inclusion of finite-temperature effects makes the blue phase thermodynamically more stable over the black phase above 135 K. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher ![]() |
Place of Publication | Editor | |||
Language | Wos | 000359860700005 | Publication Date | 2015-08-19 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 1098-0121 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 3.836 | Times cited | 124 | Open Access | |
Notes | This work was supported by the Flemish Science Founda- tion (FWO-Vl) and the Methusalem foundation of the Flem- ish government. Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Comput- ing Center (TR-Grid e-Infrastructure), and HPC infrastructure of the University of Antwerp (CalcUA), a division of the Flemish Supercomputer Center (VSC), which is funded by the Hercules foundation. C.S. acknowledges the support from Anadolu University (BAP-1407F335), and Turkish Academy of Sciences (TUBA-GEBIP). | Approved | Most recent IF: 3.836; 2015 IF: 3.736 | ||
Call Number | c:irua:127754 | Serial | 4034 | ||
Permanent link to this record | |||||
Author | da Costa, D.R.; Zarenia, M.; Chaves, A.; Farias, G.A.; Peeters, F.M. | ||||
Title | Magnetic field dependence of energy levels in biased bilayer graphene quantum dots | Type | A1 Journal article | ||
Year | 2016 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
Volume | 93 | Issue | 93 | Pages | 085401 |
Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
Abstract | Using the tight-binding approach, we study the influence of a perpendicular magnetic field on the energy levels of hexagonal, triangular, and circular bilayer graphene (BLG) quantum dots (QDs) with zigzag and armchair edges. We obtain the energy levels for AB (Bernal)-stacked BLG QDs in both the absence and the presence of a perpendicular electric field (i.e., biased BLG QDs). We find different regions in the spectrum of biased QDs with respect to the crossing point between the lowest-electron and -hole Landau levels of a biased BLG sheet. Those different regions correspond to electron states that are localized at the center, edge, or corner of the BLG QD. Quantum Hall corner states are found to be absent in circular BLG QDs. The spatial symmetry of the carrier density distribution is related to the symmetry of the confinement potential, the position of zigzag edges, and the presence or absence of interlayer inversion symmetry. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher ![]() |
Place of Publication | Editor | |||
Language | Wos | 000369402400008 | Publication Date | 2016-02-01 | |
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 | 22 | Open Access | |
Notes | ; This work was financially supported by CNPq, under Contract No. NanoBioEstruturas 555183/2005-0, PRONEX/FUNCAP, CAPES Foundation under the Process No. BEX 7178/13-1, the Flemish Science Foundation (FWO-Vl), the Bilateral programme between CNPq and FWO-Vl, and the Brazilian Program Science Without Borders (CsF). ; | Approved | Most recent IF: 3.836 | ||
Call Number | c:irua:131623 | Serial | 4038 | ||
Permanent link to this record | |||||
Author | Covaci, L.; Marsiglio, F. | ||||
Title | Proximity effect and Josephson current in clean strong/weak/strong superconducting trilayers | Type | A1 Journal article | ||
Year | 2006 | Publication | Physical Review B | Abbreviated Journal | Phys Rev B |
Volume | 73 | Issue | 1 | Pages | 014503 |
Keywords | A1 Journal article | ||||
Abstract | Recent measurements of the Josephson critical current through LSCO/LCO/LSCO thin films showed an unusually large proximity effect. Using the Bogoliubov-de Gennes equations for a tight-binding Hamiltonian we describe the proximity effect in weak links between a superconductor with critical temperature T-c and one with critical temperature T-c('), where T-c > T-c('). The weak link (N-') is therefore a superconductor above its own critical temperature and the superconducting regions are considered to have either s-wave or d-wave symmetry. We note that the proximity effect is enhanced due to the presence of superconducting correlations in the weak link. The dc Josephson current is calculated, and we obtain a nonzero value for temperatures greater than T-c(') for sizes of the weak links that can be almost an order of magnitude greater than the conventional coherence length. Considering pockets of superconductivity in the N-' layer, we show that this can lead to an even larger effect on the Josephson critical current by effectively shortening the weak link. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher ![]() |
Place of Publication | Editor | |||
Language | Wos | 000235009000103 | Publication Date | 2006-01-03 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 1098-0121 | ISBN | Additional Links | ||
Impact Factor | 3.836 | Times cited | 31 | Open Access | |
Notes | Approved | Most recent IF: 3.836; 2006 IF: 3.107 | |||
Call Number | UA @ lucian @ | Serial | 4427 | ||
Permanent link to this record | |||||
Author | Dell'Anna, L.; Perali, A.; Covaci, L.; Neilson, D. | ||||
Title | Using magnetic stripes to stabilize superfluidity in electron-hole double monolayer graphene | Type | A1 Journal article | ||
Year | 2015 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal | Phys Rev B |
Volume | 92 | Issue | 92 | Pages | 220502 |
Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
Abstract | Experiments have confirmed that double monolayer graphene does not generate finite-temperature electron-hole superfluidity, because of very strong screening of the pairing attraction. The linear dispersing energy bands in monolayer graphene block any attempt to reduce the strength of the screening. We propose a hybrid device with two sheets of monolayer graphene in a modulated periodic perpendicular magnetic field. The field preserves the isotropic Dirac cones of the original monolayers but reduces the slope of the cones, making the monolayer Fermi velocity v(F) smaller. We demonstrate that with current experimental techniques, the reduction in vF can weaken the screening sufficiently to allow electron-hole superfluidity at measurable temperatures. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher ![]() |
Place of Publication | Editor | |||
Language | Wos | 000366500100004 | Publication Date | 2015-12-14 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 1098-0121 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 3.836 | Times cited | 7 | Open Access | |
Notes | ; We thank M. Zarenia for useful discussions. L.D. acknowledges financial support from MIUR: FIRB 2012, Grant No. RBFR12NLNA_002, and PRIN, Grant No. 2010LLKJBX. A.P. and D.N. acknowledge financial support from University of Camerino FAR project CESEMN. L.C. acknowledges financial support from Flemish Science Foundation (FWO). ; | Approved | Most recent IF: 3.836; 2015 IF: 3.736 | ||
Call Number | c:irua:130211 | Serial | 4069 | ||
Permanent link to this record | |||||
Author | Mulkers, J.; Milošević, M.V.; Van Waeyenberge, B. | ||||
Title | Cycloidal versus skyrmionic states in mesoscopic chiral magnets | Type | A1 Journal article | ||
Year | 2016 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal | Phys Rev B |
Volume | 93 | Issue | 93 | Pages | 214405 |
Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
Abstract | When subjected to the interfacially induced Dzyaloshinskii-Moriya interaction, the ground state in thin ferromagnetic films with high perpendicular anisotropy is cycloidal. The period of this cycloidal state depends on the strength of the Dzyaloshinskii-Moriya interaction. In this work, we have studied the effect of confinement on the magnetic ground state and excited states, and we determined the phase diagram of thin strips and thin square platelets by means of micromagnetic calculations. We show that multiple cycloidal states with different periods can be stable in laterally confined films, where the period of the cycloids does not depend solely on the Dzyaloshinskii-Moriya interaction strength but also on the dimensions of the film. The more complex states comprising skyrmions are also found to be stable, though with higher energy. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher ![]() |
Place of Publication | Editor | |||
Language | Wos | 000377298600006 | Publication Date | 2016-06-06 | |
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 | 28 | Open Access | |
Notes | ; ; | Approved | Most recent IF: 3.836 | ||
Call Number | c:irua:133919 | Serial | 4081 | ||
Permanent link to this record | |||||
Author | Juchtmans, R.; Verbeeck, J. | ||||
Title | Orbital angular momentum in electron diffraction and its use to determine chiral crystal symmetries | Type | A1 Journal article | ||
Year | 2015 | Publication | Physical review: B: condensed matter and materials physics | Abbreviated Journal | Phys Rev B |
Volume | 92 | Issue | 92 | Pages | 134108 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | In this work we present an alternative way to look at electron diffraction in a transmission electron microscope. Instead of writing the scattering amplitude in Fourier space as a set of plane waves,we use the cylindrical Fourier transform to describe the scattering amplitude in a basis of orbital angular momentum (OAM) eigenstates. We show how working in this framework can be very convenient when investigating, e.g., rotation and screw-axis symmetries. For the latter we find selection rules on the OAM coefficients that unambiguously reveal the handedness of the screw axis. Detecting the OAM coefficients of the scattering amplitude thus offers the possibility to detect the handedness of crystals without the need for dynamical simulations, the thickness of the sample, nor the exact crystal structure. We propose an experimental setup to measure the OAM components where an image of the crystal is taken after inserting a spiral phase plate in the diffraction plane and perform multislice simulations on α quartz to demonstrate how the method indeed reveals the chirality. The experimental feasibility of the technique is discussed together with its main advantages with respect to chirality determination of screw axes. The method shows how the use of a spiral phase plate can be extended from a simple phase imaging technique to a tool to measure the local OAM decomposition of an electron wave, widening the field of interest well beyond chiral space group determination. |
||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher ![]() |
Place of Publication | Editor | |||
Language | Wos | 000362893100002 | Publication Date | 2015-10-14 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 1098-0121; 1550-235x | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 3.836 | Times cited | 16 | Open Access | |
Notes | The authors acknowledge support from the FWO (As- pirant Fonds Wetenschappelijk Onderzoek–Vlaanderen), 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; esteem2jra1; ECASJO; | Approved | Most recent IF: 3.836; 2015 IF: 3.736 | ||
Call Number | c:irua:129417 c:irua:129417UA @ admin @ c:irua:129417 | Serial | 4089 | ||
Permanent link to this record | |||||
Author | Sobrino Fernandez, M.M.; Neek-Amal, M.; Peeters, F.M. | ||||
Title | AA-stacked bilayer square ice between graphene layers | Type | A1 Journal article | ||
Year | 2015 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal | Phys Rev B |
Volume | 92 | Issue | 92 | Pages | 245428 |
Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
Abstract | Water confined between two graphene layers with a separation of a few A forms a layered two-dimensional ice structure. Using large scale molecular dynamics simulations with the adoptable ReaxFF interatomic potential we found that flat monolayer ice with a rhombic-square structure nucleates between the graphene layers which is nonpolar and nonferroelectric. We provide different energetic considerations and H-bonding results that explain the interlayer and intralayer properties of two-dimensional ice. The controversial AA stacking found experimentally [Algara-Siller et al., Nature (London) 519, 443 (2015)] is consistent with our minimum-energy crystal structure of bilayer ice. Furthermore, we predict that an odd number of layers of ice has the same lattice structure as monolayer ice, while an even number of ice layers exhibits the square ice AA stacking of bilayer ice. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher ![]() |
Place of Publication | Lancaster, Pa | Editor | ||
Language | Wos | 000366731800004 | Publication Date | 2015-12-17 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 1098-0121; 1550-235x | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 3.836 | Times cited | 40 | Open Access | |
Notes | ; This work was supported by the ESF-Eurographene project CONGRAN, and the Flemish Science Foundation (FWO-Vl). ; | Approved | Most recent IF: 3.836; 2015 IF: 3.736 | ||
Call Number | c:irua:130203 | Serial | 4127 | ||
Permanent link to this record | |||||
Author | Neek-Amal, M; Peeters, F.M. | ||||
Title | Partially hydrogenated and fluorinated graphene : structure, roughness, and negative thermal expansion | Type | A1 Journal article | ||
Year | 2015 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal | Phys Rev B |
Volume | 92 | Issue | 92 | Pages | 155430 |
Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
Abstract | The structural properties of partially hydrogenated and fluorinated graphene with different percentages of H/F atoms are investigated using molecular dynamics simulations based on reactive force field (ReaxFF) potentials. We found that the roughness of graphene varies with the percentage (p) of H or F and in both cases is maximal around p = 50%. Similar results were obtained for partially oxidized graphene. The two-dimensional area size of partially fluorinated and hydrogenated graphene exhibits a local minimum around p = 35% coverage. The lattice thermal contraction in partially functionalized graphene is found to be one order of magnitude larger than that of fully covered graphene. We also show that the armchair structure for graphene oxide (similar to the structure of fully hydrogenated and fluorinated graphene) is unstable. Our results show that the structure of partially functionalized graphene changes nontrivially with the C : H and C : F ratio as well as with temperature. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher ![]() |
Place of Publication | Lancaster, Pa | Editor | ||
Language | Wos | 000363294100005 | Publication Date | 2015-10-23 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 1098-0121; 1550-235x | 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 Flemish Science Foundation (FWO-Vl) and the Methusalem Foundation of the Flemish Government. ; | Approved | Most recent IF: 3.836; 2015 IF: 3.736 | ||
Call Number | UA @ lucian @ c:irua:129448 | Serial | 4221 | ||
Permanent link to this record | |||||
Author | Bekaert, J.; Vercauteren, S.; Aperis, A.; Komendová, L.; Prozorov, R.; Partoens, B.; Milošević, M.V. | ||||
Title | Anisotropic type-I superconductivity and anomalous superfluid density in OsB2 | Type | A1 Journal article | ||
Year | 2016 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
Volume | 94 | Issue | 94 | Pages | 144506 |
Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
Abstract | We present a microscopic study of superconductivity in OsB2 , and discuss the origin and characteristic length scales of the superconducting state. From first-principles we show that OsB2 is characterized by three different Fermi sheets, and we prove that this fermiology complies with recent quantum-oscillation experiments. Using the found microscopic properties, and experimental data from the literature, we employ Ginzburg-Landau relations to reveal that OsB2 is a distinctly type-I superconductor with a very low Ginzburg-Landau parameter κ—a rare property among compound materials. We show that the found coherence length and penetration depth corroborate the measured thermodynamic critical field. Moreover, our calculation of the superconducting gap structure using anisotropic Eliashberg theory and ab initio calculated electron-phonon interaction as input reveals a single but anisotropic gap. The calculated gap spectrum is shown to give an excellent account for the unconventional behavior of the superfluid density of OsB2 measured in experiments as a function of temperature. This reveals that gap anisotropy can explain such behavior, observed in several compounds, which was previously attributed solely to a two-gap nature of superconductivity. |
||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher ![]() |
Place of Publication | Editor | |||
Language | Wos | 000385622500009 | Publication Date | 2016-10-12 | |
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 | 19 | Open Access | |
Notes | Fonds Wetenschappelijk Onderzoek; European Cooperation in Science and Technology, MP1201 ; Vetenskapsrådet; | Approved | Most recent IF: 3.836 | ||
Call Number | CMT @ cmt @ c:irua:139020 | Serial | 4338 | ||
Permanent link to this record | |||||
Author | Doğan, F.; Covaci, L.; Kim, W.; Marsiglio, F. | ||||
Title | Emerging nonequilibrium bound state in spin-current–local-spin scattering | Type | A1 Journal article | ||
Year | 2009 | Publication | Physical Review B | Abbreviated Journal | Phys Rev B |
Volume | 80 | Issue | 10 | Pages | 104434 |
Keywords | A1 Journal article | ||||
Abstract | Magnetization reversal is a well-studied problem with obvious applicability in computer hard drives. One can accomplish a magnetization reversal in at least one of two ways: application of a magnetic field or through a spin current. The latter is more amenable to a fully quantum-mechanical analysis. We formulate and solve the problem whereby a spin current interacts with a ferromagnetic Heisenberg spin chain, to eventually reverse the magnetization of the chain. Spin flips are accomplished through both elastic and inelastic scattering. A consequence of the inelastic-scattering channel, when it is no longer energetically possible, is the occurrence of a nonequilibrium bound state, which is an emergent property of the coupled local plus itinerant spin system. For certain definite parameter values the itinerant spin lingers near the local spins for some time, before eventually leaking out as an outwardly diffusing state. This phenomenon results in spin-flip dynamics and filtering properties for this type of system. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher ![]() |
Place of Publication | Editor | |||
Language | Wos | 000270383100077 | Publication Date | 2009-09-25 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 1098-0121 | ISBN | Additional Links | ||
Impact Factor | 3.836 | Times cited | Open Access | ||
Notes | Approved | Most recent IF: 3.836; 2009 IF: 3.475 | |||
Call Number | UA @ lucian @ | Serial | 4436 | ||
Permanent link to this record |