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Author Zhao, H.J.; Wu, W.; Zhou, W.; Shi, Z.X.; Misko, V.R.; Peeters, F.M. url  doi
openurl 
  Title Reentrant dynamics of driven pancake vortices in layered superconductors Type A1 Journal article
  Year 2016 Publication Physical review B Abbreviated Journal Phys Rev B  
  Volume 94 Issue 94 Pages 024514  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract The dynamics of driven pancake vortices in layered superconductors is studied using molecular-dynamics simulations. We found that, with increasing driving force, for strong interlayer coupling, the preexisted vortex lines either directly depin or first transform to two-dimensional (2D) pinned states before they are depinned, depending on the pinning strength. In a narrow region of pinning strengths, we found an interesting repinning process, which results in a negative differential resistance. For weak interlayer coupling, individually pinned pancake vortices first form disordered 2D flow and then transform to ordered three-dimensional (3D) flow with increasing driving force. However, for extremely strong pinning, the random pinning-induced thermal-like Langevin forces melt 3D vortex lines, which results in a persistent 2D flow in the fast-sliding regime. In the intermediate regime, the peak effect is found: With increasing driving force, the moving pancake vortices first crystallize to moving 3D vortex lines, and then these 3D vortex lines are melted, leading to the appearance of a reentrant 2D flow state. Our results are summarized in a dynamical phase diagram.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000380097800006 Publication Date 2016-07-18  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2469-9950;2469-9969; ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.836 Times cited 3 Open Access  
  Notes ; We acknowledge useful discussions with C. Olson Reichhardt. This work was supported by the Natural Science Foundation of Jiangsu Province (Grant No. BK20150595), National Natural Science Foundation of China (Grants No. NSFC-U1432135 and No. 11611140101). V.R.M. acknowledges support from the “Odysseus” program of the Flemish Government and Flemish Science Foundation (FWO-Vl), the FWO-Vl, and the Research Fund of the University of Antwerp. ; Approved Most recent IF: 3.836  
  Call Number UA @ lucian @ c:irua:134943 Serial 4238  
Permanent link to this record
 

 
Author da Costa; Zarenia, M.; Chaves, A.; Pereira, J.M., Jr.; Farias, G.A.; Peeters, F.M. url  doi
openurl 
  Title Hexagonal-shaped monolayer-bilayer quantum disks in graphene : a tight-binding approach Type A1 Journal article
  Year 2016 Publication Physical review B Abbreviated Journal Phys Rev B  
  Volume 94 Issue 94 Pages 035415  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract Using the tight-binding approach, we investigate confined states in two different hybrid monolayer-bilayer systems: (i) a hexagonal monolayer area surrounded by bilayer graphene in the presence of a perpendicularly applied electric field and (ii) a hexagonal bilayer graphene dot surrounded by monolayer graphene. The dependence of the energy levels on dot size and external magnetic field is calculated. We find that the energy spectrum for quantum dots with zigzag edges consists of states inside the gap which range from dot-localized states, edge states, to mixed states coexisting together, whereas for dots with armchair edges, only dot-localized states are observed.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000379502200008 Publication Date 2016-07-11  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2469-9950;2469-9969; ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.836 Times cited 11 Open Access  
  Notes ; This work was financially supported by CNPq, under contract NanoBioEstruturas No. 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, the Brazilian Program Science Without Borders (CsF), and the Lemann Foundation. ; Approved Most recent IF: 3.836  
  Call Number UA @ lucian @ c:irua:134947 Serial 4190  
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Author Sevik, C.; Çakir, D.; Gulseren, O.; Peeters, F.M. url  doi
openurl 
  Title Peculiar piezoelectric properties of soft two-dimensional materials Type A1 Journal article
  Year 2016 Publication The journal of physical chemistry: C : nanomaterials and interfaces Abbreviated Journal J Phys Chem C  
  Volume 120 Issue 120 Pages 13948-13953  
  Keywords A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)  
  Abstract Group II-VI semiconductor honeycomb monolayers have a noncentrosymmetric crystal structure and therefore are expected to be important for nano piezoelectric device applications. This motivated us to perform first principles calculations based on density functional theory to unveil the piezoelectric properties (i.e., piezoelectric stress (e(11)) and piezoelectric strain (d(11)) coefficients) of these monolayer materials with chemical formula MX (where M = Be, Mg, Ca, Sr, Ba, Zr, Cd and X = S, Se, Te). We found that these two-dimensional materials have peculiar piezoelectric properties with d(11) coefficients 1 order of magnitude larger than those of commercially utilized bulk materials. A clear trend in their piezoelectric properties emerges, which  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Washington, D.C. Editor  
  Language Wos 000379457000010 Publication Date 2016-06-09  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1932-7447; 1932-7455 ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles  
  Impact Factor 4.536 Times cited 39 Open Access  
  Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl), the Methusalem foundation of the Flemish government and the Bilateral program FWO-TUBITAK between Flanders and Turkey. We acknowledge the support from the Scientific and Technological Research Council of Turkey (TUBITAK-115F024). Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure), and HPC infrastructure of the University of Antwerp (Cal-cUA) a division of the Flemish Supercomputer Center (VSC), which is funded by the Hercules foundation. C.S. acknowledges the support from the Scientific and Technological Research Council of Turkey (TUBITAK-113F333) and the support from Anadolu University (BAP-1407F335, -1505F200), and the Turkish Academy of Sciences (TUBA-GEBIP). ; Approved Most recent IF: 4.536  
  Call Number UA @ lucian @ c:irua:134948 Serial 4222  
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Author Verreck, D.; Van de Put, M.L.; Verhulst, A.S.; Sorée, B.; Magnus, W.; Dabral, A.; Thean, A.; Groeseneken, G. url  doi
openurl 
  Title 15-band spectral envelope function formalism applied to broken gap tunnel field-effect transistors Type P1 Proceeding
  Year 2015 Publication 18th International Workshop On Computational Electronics (iwce 2015) Abbreviated Journal  
  Volume Issue Pages  
  Keywords P1 Proceeding; Condensed Matter Theory (CMT)  
  Abstract A carefully chosen heterostructure can significantly boost the performance of tunnel field-effect transistors (TFET). Modelling of these hetero-TFETs requires a quantum mechanical (QM) approach with an accurate band structure to allow for a correct description of band-to-band-tunneling. We have therefore developed a fully QM 2D solver, combining for the first time a full zone 15-band envelope function formalism with a spectral approach, including a heterostructure basis set transformation. Simulations of GaSb/InAs broken gap TFETs illustrate the wide body capabilities and transparant transmission analysis of the formalism.  
  Address  
  Corporate Author Thesis  
  Publisher Ieee Place of Publication New york Editor  
  Language Wos 000380398200055 Publication Date 2015-10-26  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 978-0-692-51523-5 ISBN Additional Links (up) UA library record; WoS full record  
  Impact Factor Times cited Open Access  
  Notes Approved Most recent IF: NA  
  Call Number UA @ lucian @ c:irua:134998 Serial 4131  
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Author Moors, K.; Sorée, B.; Magnus, W. pdf  doi
openurl 
  Title Validity criteria for Fermi's golden rule scattering rates applied to metallic nanowires Type A1 Journal article
  Year 2016 Publication Journal of physics : condensed matter Abbreviated Journal J Phys-Condens Mat  
  Volume 28 Issue 28 Pages 365302  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract Fermi's golden rule underpins the investigation of mobile carriers propagating through various solids, being a standard tool to calculate their scattering rates. As such, it provides a perturbative estimate under the implicit assumption that the effect of the interaction Hamiltonian which causes the scattering events is sufficiently small. To check the validity of this assumption, we present a general framework to derive simple validity criteria in order to assess whether the scattering rates can be trusted for the system under consideration, given its statistical properties such as average size, electron density, impurity density et cetera. We derive concrete validity criteria for metallic nanowires with conduction electrons populating a single parabolic band subjected to different elastic scattering mechanisms: impurities, grain boundaries and surface roughness.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication London Editor  
  Language Wos 000380754400013 Publication Date 2016-07-12  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0953-8984 ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.649 Times cited 2 Open Access  
  Notes ; ; Approved Most recent IF: 2.649  
  Call Number UA @ lucian @ c:irua:135011 Serial 4274  
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Author Sarmadian, N.; Saniz, R.; Partoens, B.; Lamoen, D. pdf  url
doi  openurl
  Title First-principles study of the optoelectronic properties and photovoltaic absorber layer efficiency of Cu-based chalcogenides Type A1 Journal article
  Year 2016 Publication Journal of applied physics Abbreviated Journal J Appl Phys  
  Volume 120 Issue 120 Pages 085707  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)  
  Abstract Cu-based chalcogenides are promising materials for thin-film solar cells with more than 20% measured

cell efficiency. Using first-principles calculations based on density functional theory, the

optoelectronic properties of a group of Cu-based chalcogenides Cu2-II-IV-VI4 is studied. They are

then screened with the aim of identifying potential absorber materials for photovoltaic applications.

The spectroscopic limited maximum efficiency (SLME) introduced by Yu and Zunger [Phys. Rev.

Lett. 108, 068701 (2012)] is used as a metric for the screening. After constructing the currentvoltage

curve, the SLME is calculated from the maximum power output. The role of the nature of

the band gap, direct or indirect, and also of the absorptivity of the studied materials on the maximum

theoretical power conversion efficiency is studied. Our results show that Cu2II-GeSe4 with

II¼ Cd and Hg, and Cu2-II-SnS4 with II ¼ Cd, Hg, and Zn have a higher theoretical efficiency

compared with the materials currently used as absorber layer.
 
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000383913400074 Publication Date 2016-08-30  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0021-8979 ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.068 Times cited 29 Open Access  
  Notes We acknowledge the financial support from the FWO-Vlaanderen through project G.0150.13N and a GOA fund from the University of Antwerp. The computational resources and services used in this work were provided by the VSC (Flemish Supercomputer Center) and the HPC infrastructure of the University of Antwerp (CalcUA), bothfunded by the FWO-Vlaanderen and the Flemish Government–department EWI. Approved Most recent IF: 2.068  
  Call Number c:irua:135089 Serial 4113  
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Author Bercx, M.; Sarmadian, N.; Saniz, R.; Partoens, B.; Lamoen, D. pdf  url
doi  openurl
  Title First-principles analysis of the spectroscopic limited maximum efficiency of photovoltaic absorber layers for CuAu-like chalcogenides and silicon Type A1 Journal article
  Year 2016 Publication Physical chemistry, chemical physics Abbreviated Journal Phys Chem Chem Phys  
  Volume 18 Issue 18 Pages 20542-20549  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)  
  Abstract Chalcopyrite semiconductors are of considerable interest for application as absorber layers in thin-film photovoltaic cells. When growing films of these compounds, however, they are often found to contain CuAu-like domains, a metastable phase of chalcopyrite. It has been reported that for CuInS2, the presence of the CuAu-like phase improves the short circuit current of the chalcopyrite-based photovoltaic cell. We investigate the thermodynamic stability of both phases for a selected list of I-III-VI2 materials using a first-principles density functional theory approach. For the CuIn-VI2 compounds, the difference in formation energy between the chalcopyrite and CuAu-like phase is found to be close to 2 meV per atom, indicating a high likelihood of the presence of CuAu-like domains. Next, we calculate the spectroscopic limited maximum efficiency (SLME) of the CuAu-like phase and compare the results with those of the corresponding chalcopyrite phase. We identify several candidates with a high efficiency, such as CuAu-like CuInS2, for which we obtain an SLME of 29% at a thickness of 500 nm. We observe that the SLME can have values above the Shockley-Queisser (SQ) limit, and show that this can occur because the SQ limit assumes the absorptivity to be a step function, thus overestimating the radiative recombination in the detailed balance approach. This means that it is possible to find higher theoretical efficiencies within this framework simply by calculating the J-V characteristic with an absorption spectrum. Finally, we expand our SLME analysis to indirect band gap absorbers by studying silicon, and find that the SLME quickly overestimates the reverse saturation current of indirect band gap materials, drastically lowering their calculated efficiency.  
  Address EMAT & CMT groups, Department of Physics, University of Antwerp, Campus Groenenborger, Groenenborgerlaan 171, 2020 Antwerp, Belgium. marnik.bercx@uantwerpen.be  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Wos 000381428600058 Publication Date 2016-07-08  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1463-9076 ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles  
  Impact Factor 4.123 Times cited 34 Open Access  
  Notes We acknowledge financial support of FWO-Vlaanderen through projects G.0150.13N and G.0216.14N and ERA-NET RUS Plus/FWO, Grant G0D6515N. The computational resources and services used in this work were provided by the VSC (Flemish Supercomputer Center) and the HPC infrastructure of the University of Antwerp (CalcUA), both funded by the FWO FWOVlaanderen. Approved Most recent IF: 4.123  
  Call Number c:irua:135091 Serial 4112  
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Author Sisakht, E.T.; Fazileh, F.; Zare, M.H.; Zarenia, M.; Peeters, F.M. url  doi
openurl 
  Title Strain-induced topological phase transition in phosphorene and in phosphorene nanoribbons Type A1 Journal article
  Year 2016 Publication Physical review B Abbreviated Journal Phys Rev B  
  Volume 94 Issue 94 Pages 085417  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract Using the tight-binding (TB) approximation with inclusion of the spin-orbit interaction, we predict a topological phase transition in the electronic band structure of phosphorene in the presence of axial strains. We derive a low-energy TB Hamiltonian that includes the spin-orbit interaction for bulk phosphorene. Applying a compressive biaxial in-plane strain and perpendicular tensile strain in ranges where the structure is still stable leads to a topological phase transition. We also examine the influence of strain on zigzag phosphorene nanoribbons (zPNRs) and the formation of the corresponding protected edge states when the system is in the topological phase. For zPNRs up to a width of 100 nm the energy gap is at least three orders of magnitude larger than the thermal energy at room temperature.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000381600800004 Publication Date 2016-08-18  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2469-9950;2469-9969; ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.836 Times cited 76 Open Access  
  Notes ; This work was supported by Ministry of Science, Research and Technology, Iran. M.Z. acknowledges support as a postdoctoral fellow of the Flemish Research Foundation (FWO-Vl). ; Approved Most recent IF: 3.836  
  Call Number UA @ lucian @ c:irua:135643 Serial 4309  
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Author Klimin, S.N.; Tempere, J.; Verhelst, N.; Milošević, M.V. url  doi
openurl 
  Title Finite-temperature vortices in a rotating Fermi gas Type A1 Journal article
  Year 2016 Publication Physical review A Abbreviated Journal Phys Rev A  
  Volume 94 Issue 94 Pages 023620  
  Keywords A1 Journal article; Theory of quantum systems and complex systems; Condensed Matter Theory (CMT)  
  Abstract Vortices and vortex arrays have been used as a hallmark of superfluidity in rotated, ultracold Fermi gases. These superfluids can be described in terms of an effective field theory for a macroscopic wave function representing the field of condensed pairs, analogous to the Ginzburg-Landau theory for superconductors. Here we establish how rotation modifies this effective field theory, by rederiving it starting from the action of Fermi gas in the rotating frame of reference. The rotation leads to the appearance of an effective vector potential, and the coupling strength of this vector potential to the macroscopic wave function depends on the interaction strength between the fermions, due to a renormalization of the pair effective mass in the effective field theory. The mass renormalization derived here is in agreement with results of functional renormalization-group theory. In the extreme Bose-Einstein condensate regime, the pair effective mass tends to twice the fermion mass, in agreement with the physical picture of a weakly interacting Bose gas of molecular pairs. Then we use our macroscopic-wave-function description to study vortices and the critical rotation frequencies to form them. Equilibrium vortex state diagrams are derived and they are in good agreement with available results of the Bogoliubov-de Gennes theory and with experimental data.  
  Address  
  Corporate Author Thesis  
  Publisher American Physical Society Place of Publication New York, N.Y. Editor  
  Language Wos 000381473100001 Publication Date 2016-08-16  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2469-9934 ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.925 Times cited 6 Open Access  
  Notes ; We are grateful to G. C. Strinati and H. Warringa for valuable discussions. This research was supported by the Flemish Research Foundation Projects No. G.0115.12N, No. G.0119.12N, No. G.0122.12N, and No. G.0429.15N, by the Scientific Research Network of the Flemish Research Foundation, Grant No. WO.033.09N, and by the Research Fund of the University of Antwerp. ; Approved Most recent IF: 2.925  
  Call Number UA @ lucian @ c:irua:135686 Serial 4304  
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Author Berdiyorov, G.R.; Bahlouli, H.; Peeters, F.M. pdf  url
doi  openurl
  Title Effect of substitutional impurities on the electronic transport properties of graphene Type A1 Journal article
  Year 2016 Publication Physica. E: Low-dimensional systems and nanostructures Abbreviated Journal Physica E  
  Volume 84 Issue 84 Pages 22-26  
  Keywords A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)  
  Abstract Density-functional theory in combination with the nonequilibrium Green's function formalism is used to study the effect of substitutional doping on the electronic transport properties of hydrogen passivated zig-zag graphene nanoribbon devices. B, N and Si atoms are used to substitute carbon atoms located at the center or at the edge of the sample. We found that Si -doping results in better electronic transport as compared to the other substitutions. The transmission spectrum also depends on the location of the substitutional dopants: for single atom doping the largest transmission is obtained for edge substitutions, whereas substitutions in the middle of the sample give larger transmission for double carbon substitutions. The obtained results are explained in terms of electron localization in the system due to the presence of impurities. (C) 2016 Elsevier B.V. All rights reserved.  
  Address  
  Corporate Author Thesis  
  Publisher North-Holland Place of Publication Amsterdam Editor  
  Language Wos 000382489600004 Publication Date 2016-05-24  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1386-9477 ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.221 Times cited 17 Open Access  
  Notes ; H.B. and F.M.P. acknowledge the support from King Fahd University of Petroleum and Minerals, Saudi Arabia, under research group project RG1329-1 and RG1329-2. G.R.B. acknowledges fruitful discussions with Dr. M.E. Madjet from Qatar Environment and Energy Research Institute. ; Approved Most recent IF: 2.221  
  Call Number UA @ lucian @ c:irua:135699 Serial 4301  
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Author Dabaghmanesh, S.; Neyts, E.C.; Partoens, B. pdf  doi
openurl 
  Title van der Waals density functionals applied to corundum-type sesquioxides : bulk properties and adsorption of CH3 and C6H6 on (0001) surfaces Type A1 Journal article
  Year 2016 Publication Physical chemistry, chemical physics Abbreviated Journal Phys Chem Chem Phys  
  Volume 18 Issue 18 Pages 23139-23146  
  Keywords A1 Journal article; Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)  
  Abstract van der Waals (vdW) forces play an important role in the adsorption of molecules on the surface of solids. However, the choice of the most suitable vdW functional for different systems is an essential problem which must be addressed for different systems. The lack of a systematic study on the performance of the vdW functionals in the bulk and adsorption properties of metal-oxides motivated us to examine different vdW approaches and compute the bulk and molecular adsorption properties of alpha-Cr2O3, alpha-Fe2O3, and alpha-Al2O3. For the bulk properties, we compared our results for the heat of formation, cohesive energy, lattice parameters and bond distances between the different vdW functionals and available experimental data. Next we studied the adsorption of benzene and CH3 molecules on top of different oxide surfaces. We employed different approximations to exchange and correlation within DFT, namely, the Perdew-Burke-Ernzerhof (PBE) GGA, (PBE)+U, and vdW density functionals [ DFT(vdW-DF/DF2/optPBE/optB86b/optB88)+U] as well as DFT-D2/D3(+U) methods of Grimme for the bulk calculations and optB86b-vdW(+U) and DFT-D2(+U) for the adsorption energy calculations. Our results highlight the importance of vdW interactions not only in the adsorption of molecules, but importantly also for the bulk properties. Although the vdW contribution in the adsorption of CH3 (as a chemisorption interaction) is less important compared to the adsorption of benzene (as a physisorption interaction), this contribution is not negligible. Also adsorption of benzene on ferryl/chromyl terminated surfaces shows an important chemisorption contribution in which the vdW interactions become less significant.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Cambridge Editor  
  Language Wos 000382109300040 Publication Date 2016-07-27  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1463-9076; 1463-9084 ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles  
  Impact Factor 4.123 Times cited 6 Open Access  
  Notes ; This work was supported by the Strategic Initiative Materials in Flanders (SIM). The computational resources and services used in this work were provided by the Vlaams Supercomputer Centrum (VSC) and the HPC infrastructure of the University of Antwerp. ; Approved Most recent IF: 4.123  
  Call Number UA @ lucian @ c:irua:135701 Serial 4311  
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Author Zhang, L.; Fernández Becerra, V.; Covaci, L.; Milošević, M.V. url  doi
openurl 
  Title Electronic properties of emergent topological defects in chiral p-wave superconductivity Type A1 Journal article
  Year 2016 Publication Physical review B Abbreviated Journal Phys Rev B  
  Volume 94 Issue 94 Pages 024520  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract Chiral p-wave superconductors in applied magnetic field can exhibit more complex topological defects than just conventional superconducting vortices, due to the two-component order parameter (OP) and the broken time-reversal symmetry. We investigate the electronic properties of those exotic states, some of which contain clusters of one-component vortices in chiral components of the OP and/or exhibit skyrmionic character in the relative OP space, all obtained as a self-consistent solution of the microscopic Bogoliubov-de Gennes equations. We reveal the link between the local density of states (LDOS) of the novel topological states and the behavior of the chiral domain wall between the OP components, enabling direct identification of those states in scanning tunneling microscopy. For example, a skyrmion always contains a closed chiral domain wall, which is found to be mapped exactly by zero-bias peaks in LDOS. Moreover, the LDOS exhibits electron-hole asymmetry, which is different from the LDOS of conventional vortex states with same vorticity. Finally, we present the magnetic field and temperature dependence of the properties of a skyrmion, indicating that this topological defect can be surprisingly large in size, and can be pinned by an artificially indented nonsuperconducting closed path in the sample. These features are expected to facilitate the experimental observation of skyrmionic states, thereby enabling experimental verification of chirality in emerging superconducting materials.  
  Address  
  Corporate Author Thesis  
  Publisher American Physical Society Place of Publication New York, N.Y Editor  
  Language Wos 000381479500002 Publication Date 2016-07-26  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2469-9969 ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.836 Times cited 27 Open Access  
  Notes ; This work was supported by the Fonds Wetenschappelijk Onderzoek (FWO). ; Approved Most recent IF: 3.836  
  Call Number UA @ lucian @ c:irua:135742 Serial 4303  
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Author Schouteden, K.; Govaerts, K.; Debehets, J.; Thupakula, U.; Chen, T.; Li, Z.; Netsou, A.; Song, F.; Lamoen, D.; Van Haesendonck, C.; Partoens, B.; Park, K. pdf  url
doi  openurl
  Title Annealing-Induced Bi Bilayer on Bi2Te3 Investigated via Quasi-Particle-Interference Mapping Type A1 Journal article
  Year 2016 Publication ACS nano Abbreviated Journal Acs Nano  
  Volume 10 Issue 10 Pages 8778-8787  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)  
  Abstract Topological insulators (TIs) are renowned for their exotic topological surface states (TSSs) that reside in the top atomic layers, and hence, detailed knowledge of the surface top atomic layers is of utmost importance. Here we present the remarkable morphology changes of Bi2Te3 surfaces, which have been freshly cleaved in air, upon subsequent systematic annealing in ultrahigh vacuum and the resulting effects on the local and area-averaging electronic properties of the surface states, which are investigated by combining scanning tunneling microscopy (STM), scanning tunneling spectroscopy (STS), and Auger electron spectroscopy (AES) experiments with density functional theory (DFT) calculations. Our findings demonstrate that the annealing induces the formation of a Bi bilayer atop the Bi2Te3 surface. The adlayer results in n-type doping, and the atomic defects act as scattering centers of the TSS electrons. We also investigated the annealing-induced Bi bilayer surface on Bi2Te3 via voltage-dependent quasi-particle-interference (QPI) mapping of the surface local density of states and via comparison with the calculated constant-energy contours and QPI patterns. We observed closed hexagonal patterns in the Fourier transform of real-space QPI maps with secondary outer spikes. DFT calculations attribute these complex QPI patterns to the appearance of a “second” cone due to the surface charge transfer between the Bi bilayer and the Bi2Te3. Annealing in ultrahigh vacuum offers a facile route for tuning of the topological properties and may yield similar results for other topological materials.  
  Address Department of Physics, Virginia Tech , Blacksburg, Virginia 24061, United States  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Wos 000384399300073 Publication Date 2016-09-02  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1936-0851 ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles  
  Impact Factor 13.942 Times cited 15 Open Access  
  Notes The research in Leuven and Antwerp was supported by the Research FoundationFlanders (FWO, Belgium). The research in Leuven received additional support from the Flemish Concerted Research Action Program (BOF KULeuven, Project GOA/14/007) and the KULeuven Project GOA “Fundamental Challenges in Semiconductor Research”. Z.L. acknowledges the support from the China Scholarship Council (2011624021) and from KU Leuven Internal Funds (PDM). K.S. and J.D. acknowledge additional support from the FWO. T.C. and F.S. acknowledge the financial support of the National Key Projects for Basic Research of China (Grants 2013CB922103 and 2011CB922103), the National NaturalScience Foundation of China (Grant s 91421109, 11134005,11522432, and 11274003), the Natural Science Foundation ofJiangsu Province (Grant BK20130054), and the FundamentalResearch Funds for the Central Universities. K.P. wassupported by the U.S. National Science Foundation (DMR-1206354) and San Diego Supercomputer Center (SDSC)Comet and Gordon (DMR060009N). Approved Most recent IF: 13.942  
  Call Number EMAT @ emat @ c:irua:136269 Serial 4294  
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Author Stosic, D.; Stosic, D.; Ludermir, T.; Stosic, B.; Milošević, M.V. pdf  doi
openurl 
  Title GPU-advanced 3D electromagnetic simulations of superconductors in the Ginzburg-Landau formalism Type A1 Journal article
  Year 2016 Publication Journal of computational physics Abbreviated Journal J Comput Phys  
  Volume 322 Issue 322 Pages 183-198  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract Ginzburg-Landau theory is one of the most powerful phenomenological theories in physics, with particular predictive value in superconductivity. The formalism solves coupled nonlinear differential equations for both the electronic and magnetic responsiveness of a given superconductor to external electromagnetic excitations. With order parameter varying on the short scale of the coherence length, and the magnetic field being long-range, the numerical handling of 3D simulations becomes extremely challenging and time-consuming for realistic samples. Here we show precisely how one can employ graphics-processing units (GPUs) for this type of calculations, and obtain physics answers of interest in a reasonable time-frame – with speedup of over 100x compared to best available CPU implementations of the theory on a 2563grid. (C) 2016 Elsevier Inc. All rights reserved.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication New York Editor  
  Language Wos 000381585100010 Publication Date 2016-06-28  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0021-9991 ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.744 Times cited 4 Open Access  
  Notes ; This work was supported through research grants from Brazilian agencies CNPq (306719/2012-6, 140840/2016-8) and FACEPE (IBPG-0510-1.03/15), BOF-UA, and the Research Foundation-Flanders (FWO-Vlaanderen). ; Approved Most recent IF: 2.744  
  Call Number UA @ lucian @ c:irua:137115 Serial 4354  
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Author Ackerman, M.L.; Kumar, P.; Neek-Amal, M.; Thibado, P.M.; Peeters, F.M.; Singh, S. url  doi
openurl 
  Title Anomalous dynamical behavior of freestanding graphene membranes Type A1 Journal article
  Year 2016 Publication Physical review letters Abbreviated Journal Phys Rev Lett  
  Volume 117 Issue 117 Pages 126801  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract We report subnanometer, high-bandwidth measurements of the out-of-plane (vertical) motion of atoms in freestanding graphene using scanning tunneling microscopy. By tracking the vertical position over a long time period, a 1000-fold increase in the ability to measure space-time dynamics of atomically thin membranes is achieved over the current state-of-the-art imaging technologies. We observe that the vertical motion of a graphene membrane exhibits rare long-scale excursions characterized by both anomalous mean-squared displacements and Cauchy-Lorentz power law jump distributions.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication New York, N.Y. Editor  
  Language Wos 000383171800010 Publication Date 2016-09-13  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0031-9007 ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles  
  Impact Factor 8.462 Times cited 46 Open Access  
  Notes ; The authors thank Theodore L. Einstein, Michael F. Shlesinger, and Woodrow L. Shew for their careful reading of the manuscript and insightful comments. This work was supported by the Flemish Science Foundation (FWO-Vl) and the Methusalem Foundation of the Flemish Government. P. M. T. was supported by the Office of Naval Research under Grant No. N00014-10-1-0181 and the National Science Foundation under Grant No. DMR-0855358. M.N.-A. was supported by Iran Science Elites Federation (ISEF) under Grant No. 11/66332. ; Approved Most recent IF: 8.462  
  Call Number UA @ lucian @ c:irua:137125 Serial 4347  
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Author Khoeini, F.; Shakouri; Peeters, F.M. url  doi
openurl 
  Title Peculiar half-metallic state in zigzag nanoribbons of MoS2 : spin filtering Type A1 Journal article
  Year 2016 Publication Physical review B Abbreviated Journal Phys Rev B  
  Volume 94 Issue 94 Pages 125412  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract Layered structures of molybdenum disulfide (MoS2) belong to a new class of two-dimensional (2D) semiconductor materials in which monolayers exhibit a direct band gap in their electronic spectrum. This band gap has recently been shown to vanish due to the presence of metallic edge modes when MoS2 monolayers are terminated by zigzag edges on both sides. Here, we demonstrate that a zigzag nanoribbon of MoS2, when exposed to an external exchange field in combination with a transverse electric field, has the potential to exhibit a peculiar half-metallic nature and thereby allows electrons of only one spin direction to move. The peculiarity of such spin-selective conductors originates from a spin switch near the gap-closing region, so the allowed spin orientation can be controlled by means of an external gate voltage. It is shown that the induced half-metallic phase is resistant to random fluctuations of the exchange field as well as the presence of edge vacancies.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000383238800009 Publication Date 2016-09-09  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2469-9950;2469-9969; ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.836 Times cited 38 Open Access  
  Notes ; ; Approved Most recent IF: 3.836  
  Call Number UA @ lucian @ c:irua:137130 Serial 4360  
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Author Fatima; Oguz, I.C.; Çakir, D.; Hossain, S.; Mohottige, R.; Gulseren, O.; Oncel, N. url  doi
openurl 
  Title On the structural and electronic properties of Ir-silicide nanowires on Si(001) surface Type A1 Journal article
  Year 2016 Publication Journal of applied physics Abbreviated Journal J Appl Phys  
  Volume 120 Issue 120 Pages 095303  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract Iridium (Ir) modified Silicon (Si) (001) surface is studied with Scanning Tunneling Microscopy/Spectroscopy (STM/STS) and Density Functional Theory (DFT). A model for Ir-silicide nanowires based on STM images and ab-initio calculations is proposed. According to our model, the Ir adatom is on the top of the substrate dimer row and directly binds to the dimer atoms. I-V curves measured at 77K shows that the nanowires are metallic. DFT calculations confirm strong metallic nature of the nanowires. Published by AIP Publishing.  
  Address  
  Corporate Author Thesis  
  Publisher American Institute of Physics Place of Publication New York, N.Y. Editor  
  Language Wos 000383978100030 Publication Date 2016-09-01  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0021-8979; 1089-7550 ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.068 Times cited 7 Open Access  
  Notes ; We gratefully acknowledge the NSF (Grant No. DMR-1306101) for financial support. Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing 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. ; Approved Most recent IF: 2.068  
  Call Number UA @ lucian @ c:irua:137132 Serial 4359  
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Author Callewaert, V.; Shastry, K.; Saniz, R.; Makkonen, I.; Barbiellini, B.; Assaf, B.A.; Heiman, D.; Moodera, J.S.; Partoens, B.; Bansil, A.; Weiss, A.H.; url  doi
openurl 
  Title Positron surface state as a spectroscopic probe for characterizing surfaces of topological insulator materials Type A1 Journal article
  Year 2016 Publication Physical review B Abbreviated Journal Phys Rev B  
  Volume 94 Issue 94 Pages 115411  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract Topological insulators are attracting considerable interest due to their potential for technological applications and as platforms for exploring wide-ranging fundamental science questions. In order to exploit, fine-tune, control, and manipulate the topological surface states, spectroscopic tools which can effectively probe their properties are of key importance. Here, we demonstrate that positrons provide a sensitive probe for topological states and that the associated annihilation spectrum provides a technique for characterizing these states. Firm experimental evidence for the existence of a positron surface state near Bi2Te2Se with a binding energy of E-b = 2.7 +/- 0.2 eV is presented and is confirmed by first-principles calculations. Additionally, the simulations predict a significant signal originating from annihilation with the topological surface states and show the feasibility to detect their spin texture through the use of spin-polarized positron beams.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000383232800012 Publication Date 2016-09-06  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2469-9950;2469-9969; ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.836 Times cited 15 Open Access  
  Notes ; I.M. acknowledges discussions with M. Ervasti and A. Harju. V.C. and R.S. were supported by the FWO-Vlaanderen through Project No. G. 0224.14N. The computational resources and services used in this paper were, in part, provided by the VSC (Flemish Supercomputer Center) and the HPC infrastructure of the University of Antwerp (CalcUA), both funded by the Hercules Foundation and the Flemish Government (EWI Department). I.M. acknowledges financial support from the Academy of Finland (Projects No. 285809 and No. 293932). The work at Northeastern University was supported by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences Grant No. DE-FG02-07ER46352 and benefited from Northeastern University's Advanced Scientific Computation Center (ASCC) and the NERSC supercomputing center through DOE Grant No. DE-AC02-05CH11231. K.S. and A.W. acknowledge financial support from the National Science Foundation through Grants No. DMR-MRI-1338130 and No. DMR-1508719. D.H. received financial support from the National Science Foundation (Grant No. ECCS-1402738). J.S.M. was supported by the STC Center for Integrated Quantum Materials under NSF Grants No. DMR-1231319, No. DMR-1207469, and ONR Grant No. N00014-13-1-0301. B.A.A. also acknowledges support from the LabEx ENS-ICFP Grant No. ANR-10-LABX-0010/ANR-10-IDEX-0001-02 PSL. ; Approved Most recent IF: 3.836  
  Call Number UA @ lucian @ c:irua:137134 Serial 4362  
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Author Tomak, A.; Bacaksiz, C.; Mendirek, G.; Sahin, H.; Hur, D.; Gorgun, K.; Senger, R.T.; Birer, O.; Peeters, F.M.; Zareie, H.M. pdf  doi
openurl 
  Title Structural changes in a Schiff base molecular assembly initiated by scanning tunneling microscopy tip Type A1 Journal article
  Year 2016 Publication Nanotechnology Abbreviated Journal Nanotechnology  
  Volume 27 Issue 27 Pages 335601  
  Keywords A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)  
  Abstract We report the controlled self-organization and switching of newly designed Schiff base (E)-4-((4-(phenylethynyl) benzylidene) amino) benzenethiol (EPBB) molecules on a Au (111) surface at room temperature. Scanning tunneling microscopy and spectroscopy (STM/STS) were used to image and analyze the conformational changes of the EPBB molecules. The conformational change of the molecules was induced by using the STM tip while increasing the tunneling current. The switching of a domain or island of molecules was shown to be induced by the STM tip during scanning. Unambiguous fingerprints of the switching mechanism were observed via STM/STS measurements. Surface-enhanced Raman scattering was employed, to control and identify quantitatively the switching mechanism of molecules in a monolayer. Density functional theory calculations were also performed in order to understand the microscopic details of the switching mechanism. These calculations revealed that the molecular switching behavior stemmed from the strong interaction of the EPBB molecules with the STM tip. Our approach to controlling intermolecular mechanics provides a path towards the bottom-up assembly of more sophisticated molecular machines.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Bristol Editor  
  Language Wos 000383780500012 Publication Date 2016-07-05  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0957-4484 ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.44 Times cited 2 Open Access  
  Notes ; The authors acknowledge financial support from TUBITAK (PROJECT NO: 112T507). This work was also supported by the Flemish Science Foundation (FWO-Vl). Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid-Infrastructure). HS is supported by an FWO Pegasus Long Marie Curie Fellowship. ; Approved Most recent IF: 3.44  
  Call Number UA @ lucian @ c:irua:137155 Serial 4363  
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Author Van der Donck, M.; De Beule, C.; Partoens, B.; Peeters, F.M.; Van Duppen, B. doi  openurl
  Title Piezoelectricity in asymmetrically strained bilayer graphene Type A1 Journal article
  Year 2016 Publication 2D materials Abbreviated Journal 2D Mater  
  Volume 3 Issue 3 Pages 035015  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract We study the electronic properties of commensurate faulted bilayer graphene by diagonalizing the one-particle Hamiltonian of the bilayer system in a complete basis of Bloch states of the individual graphene layers. Our novel approach is very general and can be easily extended to any commensurate graphene-based heterostructure. Here, we consider three cases: (i) twisted bilayer graphene, (ii) bilayer graphene where triaxial stress is applied to one layer and (iii) bilayer graphene where uniaxial stress is applied to one layer. We show that the resulting superstructures can be divided into distinct classes, depending on the twist angle or the magnitude of the induced strain. The different classes are distinguished from each other by the interlayer coupling mechanism, resulting in fundamentally different low-energy physics. For the cases of triaxial and uniaxial stress, the individual graphene layers tend to decouple and we find significant charge transfer between the layers. In addition, this piezoelectric effect can be tuned by applying a perpendicular electric field. Finally, we show how our approach can be generalized to multilayer systems.  
  Address  
  Corporate Author Thesis  
  Publisher IOP Publishing Place of Publication Bristol Editor  
  Language Wos 000384072500003 Publication Date 2016-08-31  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2053-1583 ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles  
  Impact Factor 6.937 Times cited 10 Open Access  
  Notes ; This work was supported by the Research Foundation-Flanders (FWO-Vl) through aspirant research grants to MVDD, CDB, and BVD. ; Approved Most recent IF: 6.937  
  Call Number UA @ lucian @ c:irua:137203 Serial 4361  
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Author De Beule, C.; Ziani, N.T.; Zarenia, M.; Partoens, B.; Trauzettel, B. url  doi
openurl 
  Title Correlation and current anomalies in helical quantum dots Type A1 Journal article
  Year 2016 Publication Physical review B Abbreviated Journal Phys Rev B  
  Volume 94 Issue 94 Pages 155111  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract We theoretically investigate the ground-state properties of a quantum dot defined on the surface of a strong three-dimensional time-reversal invariant topological insulator. Confinement is realized by ferromagnetic barriers and Coulomb interaction is treated numerically for up to seven electrons in the dot. Experimentally relevant intermediate interaction strengths are considered. The topological origin of the dot has several consequences: (i) spin polarization increases and the ground state exhibits quantum phase transitions at specific angular momenta as a function of interaction strength, (ii) the onset of Wigner correlations takes place mainly in one spin channel, and (iii) the ground state is characterized by a robust persistent current that changes sign as a function of the distance from the center of the dot.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000385242200001 Publication Date 2016-10-07  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2469-9950;2469-9969; ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.836 Times cited 3 Open Access  
  Notes ; We thank F. Cavaliere, F. Crepin, C. Felser, and B. Yan for interesting discussions, and S. Curreli for performing the finite-element calculation of the magnetic field in COMSOL. C.D.B. and M.Z. are supported by the Flemish Research Foundation (FWO). N.T.Z. and B.T. acknowledge financial support by the DFG (SPP1666 and SFB1170 “ToCoTronics”), the Helmholtz Foundation (VITI), and the ENB Graduate School on “Topological Insulators.” ; Approved Most recent IF: 3.836  
  Call Number UA @ lucian @ c:irua:137234 Serial 4351  
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Author Kiymaz, D.; Yagmurcukardes, M.; Tomak, A.; Sahin, H.; Senger, R.T.; Peeters, F.M.; Zareie, H.M.; Zafer, C. doi  openurl
  Title Controlled growth mechanism of poly (3-hexylthiophene) nanowires Type A1 Journal article
  Year 2016 Publication Nanotechnology Abbreviated Journal Nanotechnology  
  Volume 27 Issue 27 Pages 455604  
  Keywords A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)  
  Abstract Synthesis of 1D-polymer nanowires by a self-assembly method using marginal solvents is an attractive technique. While the formation mechanism is poorly understood, this method is essential in order to control the growth of nanowires. Here we visualized the time-dependent assembly of poly (3-hexyl-thiophene-2,5-diyl) (P3HT) nanowires by atomic force microscopy and scanning tunneling microscopy. The assembly of P3HT nanowires was carried out at room temperature by mixing cyclohexanone (CHN), as a poor solvent, with polymer solution in 1,2-dichlorobenzene (DCB). Both pi-pi stacking and planarization, obtained at the mix volume ratio of P3HT (in DCB):CHN (10:7), were considered during the investigation. We find that the length of nanowires was determined by the ordering of polymers in the polymer repetition direction. Additionally, our density functional theory calculations revealed that the presence of DCB and CHN molecules that stabilize the structural distortions due to tail group of polymers was essential for the core-wire formation.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Bristol Editor  
  Language Wos 000386132600003 Publication Date 2016-10-11  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0957-4484 ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.44 Times cited 24 Open Access  
  Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Methusalem foundation of the Flemish government. Computational resources were provided by TUBITAK ULAKBIM, the High Performance and Grid Computing Center (TR-Grid e-Infrastructure), and the HPC infrastructure of the University of Antwerp (CalcUA), a division of the Flemish Supercomputer Center (VSC), which is funded by the Hercules Foundation. HS is supported by a FWO Pegasus-Long Marie Curie Fellowship. HS and RTS acknowledge support from TUBITAK through Project No. 114F397. Also, DA is supported by the Scientific Research Project Fund of Ege University (Project Nr: 12GEE011). ; Approved Most recent IF: 3.44  
  Call Number UA @ lucian @ c:irua:138159 Serial 4350  
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Author Mirzakhani, M.; Zarenia, M.; da Costa, D.R.; Ketabi, S.A.; Peeters, F.M. url  doi
openurl 
  Title Energy levels of ABC-stacked trilayer graphene quantum dots with infinite-mass boundary conditions Type A1 Journal article
  Year 2016 Publication Physical review B Abbreviated Journal Phys Rev B  
  Volume 94 Issue 94 Pages 165423  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract Using the continuum model, we investigate the confined states and the corresponding wave functions of ABC-stacked trilayer graphene (TLG) quantum dots (QDs). First, a general infinite-mass boundary condition is derived and applied to calculate the electron and hole energy levels of a circular QD in both the absence and presence of a perpendicular magnetic field. Our analytical results for the energy spectra agree with those obtained by using the tight-binding model, where a TLG QD is surrounded by a staggered potential. Our findings show that (i) the energy spectrum exhibits intervalley symmetry E-K(e)(m) = -E-K'(h)(m) for the electron (e) and hole (h) states, where m is the angular momentum quantum number, (ii) the zero-energy Landau level (LL) is formed by the magnetic states with m <= 0 for both Dirac valleys, that is different from monolayer and bilayer graphene QD with infinite-mass potential in which only one of the cones contributes, and (iii) groups of three quantum Hall edge states in the tight-binding magnetic spectrum approach the zero LL, which results from the layer symmetry in TLG QDs.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000386168000011 Publication Date 2016-10-19  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2469-9950;2469-9969; ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.836 Times cited 9 Open Access  
  Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl), the Brazilian Council for Research (CNPq), the Science without Borders program, PRONEX/FUNCAP, and CAPES foundation. ; Approved Most recent IF: 3.836  
  Call Number UA @ lucian @ c:irua:138174 Serial 4353  
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Author Xiao, Y.M.; Xu, W.; Van Duppen, B.; Peeters, F.M. url  doi
openurl 
  Title Infrared to terahertz optical conductivity of n-type and p-type monolayer MoS2 in the presence of Rashba spin-orbit coupling Type A1 Journal article
  Year 2016 Publication Physical review B Abbreviated Journal Phys Rev B  
  Volume 94 Issue 94 Pages 155432  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract We investigate the effect of Rashba spin-orbit coupling (SOC) on the optoelectronic properties of n- and p-type monolayer MoS2. The optical conductivity is calculated within the Kubo formalism. We find that the spin-flip transitions enabled by the Rashba SOC result in a wide absorption window in the optical spectrum. Furthermore, we evaluate the effects of the polarization direction of the radiation, temperature, carrier density, and the strength of the Rashba spin-orbit parameter on the optical conductivity. We find that the position, width, and shape of the absorption peak or absorption window can be tuned by varying these parameters. This study shows that monolayer MoS2 can be a promising tunable optical and optoelectronic material that is active in the infrared to terahertz spectral range.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000386097800003 Publication Date 2016-10-18  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2469-9950;2469-9969; ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.836 Times cited 20 Open Access  
  Notes ; Y.M.X. acknowledges financial support from the China Scholarship Council (CSC). This work was also supported by the National Natural Science Foundation of China (Grant No. 11574319), Ministry of Science and Technology of China (Grant No. 2011YQ130018), Department of Science and Technology of Yunnan Province, and by the Chinese Academy of Sciences. B.V.D. is supported by a Ph.D. fellowship from the Flemish Science Foundation. ; Approved Most recent IF: 3.836  
  Call Number UA @ lucian @ c:irua:138175 Serial 4355  
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Author Yagmurcukardes, M.; Torun, E.; Senger, R.T.; Peeters, F.M.; Sahin, H. url  doi
openurl 
  Title Mg(OH)2-WS2 van der Waals heterobilayer : electric field tunable band-gap crossover Type A1 Journal article
  Year 2016 Publication Physical review B Abbreviated Journal Phys Rev B  
  Volume 94 Issue 94 Pages 195403  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract Magnesium hydroxide [Mg(OH)(2)] has a layered brucitelike structure in its bulk form and was recently isolated as a new member of two-dimensional monolayer materials. We investigated the electronic and optical properties of monolayer crystals of Mg(OH)(2) and WS2 and their possible heterobilayer structure by means of first-principles calculations. It was found that both monolayers of Mg(OH)(2) and WS2 are direct-gap semiconductors and these two monolayers form a typical van der Waals heterostructure with a weak interlayer interaction and a type-II band alignment with a staggered gap that spatially separates electrons and holes. We also showed that an out-of-plane electric field induces a transition from a staggered to a straddling-type heterojunction. Moreover, by solving the Bethe-Salpeter equation on top of single-shot G(0)W(0) calculations, we show that the low-energy spectrum of the heterobilayer is dominated by the intralyer excitons of the WS2 monolayer. Because of the staggered interfacial gap and the field-tunable energy-band structure, the Mg(OH)(2)-WS2 heterobilayer can become an important candidate for various optoelectronic device applications in nanoscale.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000386769400007 Publication Date 2016-11-03  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2469-9950;2469-9969; ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.836 Times cited 38 Open Access  
  Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Methusalem foundation of the Flemish government. Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure). H.S. is supported by a FWOPegasus Long Marie Curie Fellowship. H.S. and R.T.S. acknowledge support from TUBITAK through Project No. 114F397. H.S. acknowledges support from Bilim Akademisi – The Science Academy, Turkey, under the BAGEP program. ; Approved Most recent IF: 3.836  
  Call Number UA @ lucian @ c:irua:138205 Serial 4364  
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Author Moldovan, D.; Peeters, F.M. doi  openurl
  Title Atomic Collapse in Graphene Type P1 Proceeding
  Year 2016 Publication Nanomaterials For Security Abbreviated Journal  
  Volume Issue Pages 3-17  
  Keywords P1 Proceeding; Engineering sciences. Technology; Condensed Matter Theory (CMT)  
  Abstract When the charge Z of an atom exceeds the critical value of 170, it will undergo a process called atomic collapse which triggers the spontaneous creation of electron-positron pairs. The high charge requirements have prevented the observation of this phenomenon with real atomic nuclei. However, thanks to the relativistic nature of the carriers in graphene, the same physics is accessible at a much lower scale. The atomic collapse analogue in graphene is realized using artificial nuclei which can be created via the deposition of impurities on the surface of graphene or using charged vacancies. These supercritically charged artificial nuclei trap electrons in a sequence of quasi-bound states which can be observed experimentally as resonances in the local density of states.  
  Address  
  Corporate Author Thesis  
  Publisher Springer Place of Publication Dordrecht Editor  
  Language Wos 000386506200001 Publication Date 2016-07-20  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 978-94-017-7593-9; 978-94-017-7591-5 ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles  
  Impact Factor Times cited 3 Open Access  
  Notes ; ; Approved Most recent IF: NA  
  Call Number UA @ lucian @ c:irua:138237 Serial 4348  
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Author Bekaert, J.; Vercauteren, S.; Aperis, A.; Komendová, L.; Prozorov, R.; Partoens, B.; Milošević, M.V. url  doi
openurl 
  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 (up) 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  
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Author Milovanović, S.P.; Peeters, F.M. doi  openurl
  Title Strain controlled valley filtering in multi-terminal graphene structures Type A1 Journal article
  Year 2016 Publication Applied physics letters Abbreviated Journal Appl Phys Lett  
  Volume 109 Issue 109 Pages 203108  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract Valley-polarized currents can be generated by local straining of multi-terminal graphene devices. The pseudo-magnetic field created by the deformation allows electrons from only one valley to transmit, and a current of electrons from a single valley is generated at the opposite side of the locally strained region. We show that valley filtering is most effective with bumps of a certain height and width. Despite the fact that the highest contribution to the polarized current comes from electrons from the lowest sub-band, contributions of other sub-bands are not negligible and can significantly enhance the output current. Published by AIP Publishing.  
  Address  
  Corporate Author Thesis  
  Publisher American Institute of Physics Place of Publication New York, N.Y. Editor  
  Language Wos 000388000000049 Publication Date 2016-11-16  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0003-6951; 1077-3118 ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.411 Times cited 50 Open Access  
  Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl) and the European Science Foundation (ESF) under the EUROCORES Program EuroGRAPHENE within the project CONGRAN. ; Approved Most recent IF: 3.411  
  Call Number UA @ lucian @ c:irua:139165 Serial 4463  
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Author Shumilin, A.V.; Baranov, V.V.; Kabanov, V.V. url  doi
openurl 
  Title Upper critical field in the model with finite-range interaction between electrons Type A1 Journal article
  Year 2016 Publication Physical review B Abbreviated Journal Phys Rev B  
  Volume 94 Issue 94 Pages 174506  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract We develop a theory of the upper critical field in a BCS superconductor with a nonlocal interaction between electrons. We have shown that the nonlocal interaction is characterized by the parameter k(F)rho(0), where k(F) is the Fermi momentum and rho(0) is the radius of electron-electron interaction. The presence of the external magnetic field leads to the generation of additional components of the order parameter with different angular momenta. This effect leads to the enhancement of the upper critical field above the orbital limiting field. In addition the upward curvature in the temperature dependence of H-c2 (T) in the clean limit is predicted. The impurity scattering suppresses the effect in the dirty limit.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000387884100005 Publication Date 2016-11-14  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2469-9950;2469-9969; ISBN Additional Links (up) UA library record; WoS full record  
  Impact Factor 3.836 Times cited Open Access  
  Notes ; ; Approved Most recent IF: 3.836  
  Call Number UA @ lucian @ c:irua:139166 Serial 4365  
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Author Yagmurcukardes, M.; Senger, R.T.; Peeters, F.M.; Sahin, H. url  doi
openurl 
  Title Mechanical properties of monolayer GaS and GaSe crystals Type A1 Journal article
  Year 2016 Publication Physical review B Abbreviated Journal Phys Rev B  
  Volume 94 Issue 94 Pages 245407  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract The mechanical properties of monolayer GaS and GaSe crystals are investigated in terms of their elastic constants: in-plane stiffness (C), Poisson ratio (nu), and ultimate strength (sigma(U)) by means of first-principles calculations. The calculated elastic constants are compared with those of graphene and monolayer MoS2. Our results indicate that monolayer GaS is a stiffer material than monolayer GaSe crystals due to the more ionic character of the Ga-S bonds than the Ga-Se bonds. Although their Poisson ratio values are very close to each other, 0.26 and 0.25 for GaS and GaSe, respectively, monolayer GaS is a stronger material than monolayer GaSe due to its slightly higher sU value. However, GaS and GaSe crystals are found to be more ductile and flexible materials than graphene and MoS2. We have also analyzed the band-gap response of GaS and GaSe monolayers to biaxial tensile strain and predicted a semiconductor-metal crossover after 17% and 14% applied strain, respectively, for monolayer GaS and GaSe. In addition, we investigated how the mechanical properties are affected by charging. We found that the flexibility of single layer GaS and GaSe displays a sharp increase under 0.1e/cell charging due to the repulsive interactions between extra charges located on chalcogen atoms. These charging-controllable mechanical properties of single layers of GaS and GaSe can be of potential use for electromechanical applications.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000389503400008 Publication Date 2016-12-05  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2469-9950;2469-9969; ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.836 Times cited 108 Open Access  
  Notes ; Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure). H.S. acknowledges support from Bilim Akademisi-The Science Academy, Turkey under the BAGEP program. R.T.S. acknowledges the support from TUBITAK through project 114F397. ; Approved Most recent IF: 3.836  
  Call Number UA @ lucian @ c:irua:139229 Serial 4356  
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