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Author Bercx, M.; Partoens, B.; Lamoen, D.
Title Quantitative modeling of secondary electron emission from slow-ion bombardment on semiconductors Type A1 Journal article
Year 2019 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 99 Issue (down) 8 Pages 085413
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Abstract When slow ions incident on a surface are neutralized, the excess potential energy is passed on to an electron inside the surface, leading to emission of secondary electrons. The microscopic description of this process, as

well as the calculation of the secondary electron yield, is a challenging problem due to its complexity as well

as its sensitivity to surface properties. One of the first quantitative descriptions was articulated in the 1950s by

Hagstrum, who based his calculation on a parametrization of the density of states of the material. In this paper, we

present a model for calculating the secondary electron yield, derived from Hagstrum’s initial approach. We use

first-principles density functional theory calculations to acquire the necessary input and introduce the concept of

electron cascades to Hagstrum’s model in order to improve the calculated spectra, as well as remove its reliance

on fitting parameters. We apply our model to He+ and Ne+ ions incident on Ge(111) and Si(111) and obtain

yield spectra that match closely to the experimental results of Hagstrum.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000458367800010 Publication Date 2019-02-11
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 5 Open Access OpenAccess
Notes We would like to thank Prof. D. Depla for the useful discussions on the secondary electron yield. Furthermore, we acknowledge financial support of FWO-Vlaanderen through project G.0216.14N. 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 FWOVlaanderen and the Flemish Government-department EWI. Approved Most recent IF: 3.836
Call Number EMAT @ emat @UA @ admin @ c:irua:157174 Serial 5154
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Author Bafekry, A.; Neek-Amal, M.
Title Tuning the electronic properties of graphene-graphitic carbon nitride heterostructures and heterojunctions by using an electric field Type A1 Journal article
Year 2020 Publication Physical Review B Abbreviated Journal Phys Rev B
Volume 101 Issue (down) 8 Pages 085417-10
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Integration of graphene-based two-dimensional materials is essential for nanoelectronics applications. Using density-functional theory, we systematically investigate the electronic properties of vertically stacked graphene-graphitic carbon nitrides (GE/GCN). We also studied the covalently lateral stitched graphene-graphitic carbon nitrides (GE-GCN heterojunctions). The effects of perpendicular electric field on the electronic properties of six different heterostructures, i.e., (i) one layer of GE on top of a layer of CnNm with (n, m) = (3,1), (3,4), and (4,3) and (ii) three heterostructures CnNm/Cn'Nm', where (n, m) not equal (n', m') are elucidated. The most important calculated features are (i) the systems GE/C3N4, C3N/C3N4, GE-C3N, GE-C4N3, and C3N-C3N4 exhibit semiconducting characteristics having small band gaps of Delta(0)=20, 250, 100, 100, 80 meV, respectively while (ii) the systems GE/C4N3, C3N/C4N3, and C3N-C4N3 show ferromagnetic-metallic properties. In particular, we found that, in semiconducting heterostructures, the band gap increases nontrivially with increasing the absolute value of the applied perpendicular electric field. This work is useful for designing heterojunctions and heterostructures made of graphene and other two-dimensional materials such as those proposed in recent experiments [X. Liu and M. C. Hersam Sci. Adv. 5, 6444 (2019)].
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000515659700007 Publication Date 2020-02-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.7 Times cited 24 Open Access
Notes ; ; Approved Most recent IF: 3.7; 2020 IF: 3.836
Call Number UA @ admin @ c:irua:167760 Serial 6640
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Author Ozbal, G.; Senger, R.T.; Sevik, C.; Sevincli, H.
Title Ballistic thermoelectric properties of monolayer semiconducting transition metal dichalcogenides and oxides Type A1 Journal article
Year 2019 Publication Physical review B Abbreviated Journal
Volume 100 Issue (down) 8 Pages 085415
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Combining first-principles calculations with Landauer-Mittiker formalism, ballistic thermoelectric transport properties of semiconducting two-dimensional transition metal dichalcogenides (TMDs) and oxides (TMOs) (namely MX2 with M = Cr, Mo, W, Ti, Zr, Hf; X = O, S, Se, Te) are investigated in their 2H and 1T phases. Having computed structural, as well as ballistic electronic and phononic transport properties for all structures, we report the thermoelectric properties of the semiconducting ones. We find that 2H phases of four of the studied structures have very promising thermoelectric properties, unlike their 1T phases. The maximum room temperature p-type thermoelectric figure of merit (ZT) of 1.57 is obtained for 2H-HfSe2, which can be as high as 3.30 at T = 800 K. Additionally, 2H-ZrSe2, 2H-ZrTe2, and 2H-HfS2 have considerable ZT values (both nand p-type), that are above 1 at room temperature. The 1T phases of Zr and Hf-based oxides possess relatively high power factors, however their high lattice thermal conductance values limit their ZT values to below 1 at room temperature.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000480389100007 Publication Date 2019-08-12
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited Open Access
Notes Approved no
Call Number UA @ admin @ c:irua:193773 Serial 7549
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Author Demiroglu, I.; Sevik, C.
Title Extraordinary negative thermal expansion of two-dimensional nitrides : a comparative ab initio study of quasiharmonic approximation and molecular dynamics simulations Type A1 Journal article
Year 2021 Publication Physical Review B Abbreviated Journal Phys Rev B
Volume 103 Issue (down) 8 Pages 085430
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Thermal expansion behavior of two-dimensional (2D) nitrides and graphene were studied by ab initio molecular dynamics (MD) simulations as well as quasiharmonic approximation (QHA). Anharmonicity of the acoustic phonon modes are related to the unusual negative thermal expansion (NTE) behavior of the nitrides. Our results also hint that direct ab initio MD simulations are a more elaborate method to investigate thermal expansion behavior of 2D materials than the QHA. Nevertheless, giant NTE coefficients are found for h-GaN and h-AlN within the covered temperature range 100-600 K regardless of the chosen computational method. This unusual NTE of 2D nitrides is reasoned with the out-of-plane oscillations related to the rippling behavior of the monolayers.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000620346100007 Publication Date 2021-02-22
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited Open Access OpenAccess
Notes Approved Most recent IF: 3.836
Call Number UA @ admin @ c:irua:176671 Serial 7956
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Author Nogaret, A.; Lambert, N.J.; Peeters, F.M.
Title Electrically induced spin resonance fluorescence : 2 : fluorescence spectra Type A1 Journal article
Year 2007 Publication Physical Review B Abbreviated Journal Phys Rev B
Volume 76 Issue (down) 7 Pages
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We model the fluorescence spectra of planar spin oscillators to find conditions that maximize spin resonance fluorescence. Spin oscillators perform Rabi oscillations under the effect of a periodic effective magnetic field caused by the winding motion of an electron in a gradient of magnetic field. We show that, despite the weak coupling of the spin magnetic dipole to the vacuum, spin oscillators excited by a direct current output a few nanowatts of microwave power, which is comparable to the best microwave sources. The large quantum efficiency relies on the combination of two effects. On the one hand, the spontaneous emission rate is enhanced by the synchronization of spin oscillators, which interact through the microwave field that they emit. On the other hand, the huge Rabi frequencies experienced by spin oscillators promote spins into upper levels of Zeeman transitions, from which a radiative cascade is triggered. We demonstrate different regimes of fluorescence which correspond to different values of the Rabi period relative to the spontaneous decay time and to the oscillator dwell time in the gradient of magnetic field. We investigate the device parameters which make these regimes experimentally accessible and find conditions that optimize microwave output. We find that microwave emission is centered around the cutoff frequency of spin oscillators. This has the advantage that the peak emission frequency may be tuned from zero continuously up to a few hundred gigahertz using an electrostatic gate. Quite remarkably for a spintronics effect, electrically induced spin resonance fluorescence does not require the injection of a spin polarized current. In fact, we show that microwave spectra are mostly independent of the incoming spin polarization except for magnetic waveguides which are shorter than a certain critical length, which we will specify.
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000249155300092 Publication Date 2007-08-09
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 8 Open Access
Notes Approved Most recent IF: 3.836; 2007 IF: 3.172
Call Number UA @ lucian @ c:irua:66118 Serial 898
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Author Cavalcante, L.S.; Chaves, A.; da Costa, D.R.; Farias, G.A.; Peeters, F.M.
Title All-strain based valley filter in graphene nanoribbons using snake states Type A1 Journal article
Year 2016 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 94 Issue (down) 7 Pages 075432
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract A pseudomagnetic field kink can be realized along a graphene nanoribbon using strain engineering. Electron transport along this kink is governed by snake states that are characterized by a single propagation direction. Those pseudomagnetic fields point towards opposite directions in the K and K' valleys, leading to valley polarized snake states. In a graphene nanoribbon with armchair edges this effect results in a valley filter that is based only on strain engineering. We discuss how to maximize this valley filtering by adjusting the parameters that define the stress distribution along the graphene ribbon.
Address
Corporate Author Thesis
Publisher American Physical Society Place of Publication New York, N.Y Editor
Language Wos 000381889300002 Publication Date 2016-08-23
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 29 Open Access
Notes ; Discussions with R. Grassi are gratefully acknowledged. This work was supported by the Brazilian Council for Research (CNPq), under the PRONEX/FUNCAP and Science Without Borders (SWB) programs, CAPES, the Lemann Foundation, and the Flemish Science Foundation (FWO-Vl). ; Approved Most recent IF: 3.836
Call Number UA @ lucian @ c:irua:144667 Serial 4639
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Author Saberi-Pouya, S.; Vazifehshenas, T.; Salavati-Fard, T.; Farmanbar, M.; Peeters, F.M.
Title Strong anisotropic optical conductivity in two-dimensional puckered structures : the role of the Rashba effect Type A1 Journal article
Year 2017 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 96 Issue (down) 7 Pages 075411
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract within the Kubo formalism. We show that the anisotropic Rashba effect caused by an external field significantly changes the magnitude of the spin splitting. Furthermore, we obtain an analytical expression for the longitudinal optical conductivity associated with interband transitions as a function of the frequency for arbitrary polarization angle. We find that the diagonal components of the optical conductivity tensor are direction dependent and the optical absorption spectrum exhibits a strongly anisotropic absorption window. The height and width of this absorption window are very sensitive to the anisotropy of the system. While the height of absorption peak increases with increasing effective mass anisotropy ratio, the peak intensity is larger when the light polarization is along the armchair direction. Moreover, the absorption peak width becomes broader as the density-of-states mass or Rashba interaction is enhanced. These features in the optical absorption spectrum can be used to determine parameters relevant for spintronics.
Address
Corporate Author Thesis
Publisher American Physical Society Place of Publication New York, N.Y Editor
Language Wos 000407097100005 Publication Date 2017-08-09
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 16 Open Access
Notes ; ; Approved Most recent IF: 3.836
Call Number UA @ lucian @ c:irua:145725 Serial 4752
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Author Li, L.L.; Peeters, F.M.
Title Quantum transport in defective phosphorene nanoribbons : effects of atomic vacancies Type A1 Journal article
Year 2018 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 97 Issue (down) 7 Pages 075414
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Defects are almost inevitably present in realistic materials and defective materials are expected to exhibit very different properties than their nondefective (perfect) counterparts. Here, using a combination of the tight-binding approach and the scattering matrix formalism, we investigate the electronic transport properties of defective phosphorene nanoribbons (PNRs) containing atomic vacancies. We find that for both armchair PNRs (APNRs) and zigzag PNRs (ZPNRs), single vacancies can create quasilocalized states, which can affect their conductance. With increasing vacancy concentration, three different transport regimes are identified: ballistic, diffusive, and Anderson localized ones. In particular, ZPNRs that are known to be metallic due to the presence of edge states become semiconducting: edge conductance vanishes and transport gap appears due to Anderson localization. Moreover, we find that for a fixed vacancy concentration, both APNRs and ZPNRs of narrower width and/or longer length are more sensitive to vacancy disorder than their wider and/or shorter counterparts, and that for the same ribbon length and width, ZPNRs are more sensitive to vacancy disorder than APNRs.
Address
Corporate Author Thesis
Publisher American Physical Society Place of Publication New York, N.Y Editor
Language Wos 000424901800006 Publication Date 2018-02-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 30 Open Access
Notes ; This work was financially supported by the Flemish Science Foundation (FWO-Vl), the FLAG-ERA TRANS 2D TMD, and by the Chinese Academy of Sciences (CAS). ; Approved Most recent IF: 3.836
Call Number UA @ lucian @ c:irua:149255UA @ admin @ c:irua:149255 Serial 4946
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Author Torun, E.; Sahin, H.; Chaves, A.; Wirtz, L.; Peeters, F.M.
Title Ab initio and semiempirical modeling of excitons and trions in monolayer TiS3 Type A1 Journal article
Year 2018 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 98 Issue (down) 7 Pages 075419
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We explore the electronic and the optical properties of monolayer TiS3, which shows in-plane anisotropy and is composed of a chain-like structure along one of the lattice directions. Together with its robust direct band gap, which changes very slightly with stacking order and with the thickness of the sample, the anisotropic physical properties of TiS3 make the material very attractive for various device applications. In this study, we present a detailed investigation on the effect of the crystal anisotropy on the excitons and the trions of the TiS3 monolayer. We use many-body perturbation theory to calculate the absorption spectrum of anisotropic TiS3 monolayer by solving the Bethe-Salpeter equation. In parallel, we implement and use a Wannier-Mott model for the excitons that takes into account the anisotropic effective masses and Coulomb screening, which are obtained from ab initio calculations. This model is then extended for the investigation of trion states of monolayer TiS3. Our calculations indicate that the absorption spectrum of monolayer TiS3 drastically depends on the polarization of the incoming light, which excites different excitons with distinct binding energies. In addition, the binding energies of positively and the negatively charged trions are observed to be distinct and they exhibit an anisotropic probability density distribution.
Address
Corporate Author Thesis
Publisher American Physical Society Place of Publication New York, N.Y Editor
Language Wos 000442342100002 Publication Date 2018-08-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 10 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl) and the FLAG-ERA project TRANS-2D-TMD. H.S. acknowledges financial support from TUBITAK under Project No. 117F095. A.C. acknowledges support from the Brazilian Research Council (CNPq), through the PRONEX/FUNCAP and Science Without Borders programs, and from the Lemann Foundation. E.T. and L.W. acknowledge support from the National Research Fund, Luxembourg (IN-TER/ANR/13/20/NANOTMD). ; Approved Most recent IF: 3.836
Call Number UA @ lucian @ c:irua:153721UA @ admin @ c:irua:153721 Serial 5076
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Author Houben, K.; Jochum, J.K.; Lozano, D.P.; Bisht, M.; Menendez, E.; Merkel, D.G.; Ruffer, R.; Chumakov, A., I; Roelants, S.; Partoens, B.; Milošević, M.V.; Peeters, F.M.; Couet, S.; Vantomme, A.; Temst, K.; Van Bael, M.J.
Title In situ study of the \alpha-Sn to \beta-Sn phase transition in low-dimensional systems : phonon behavior and thermodynamic properties Type A1 Journal article
Year 2019 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 100 Issue (down) 7 Pages 075408
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The densities of phonon states of thin Sn films on InSb substrates are determined during different stages of the alpha-Sn to beta-Sn phase transition using nuclear inelastic x-ray scattering. The vibrational entropy and internal energy per atom as a function of temperature are obtained by numerical integration of the phonon density of states. The free energy as a function of temperature for the nanoscale samples is compared to the free energy obtained from ab initio calculations of bulk tin in the alpha-Sn and beta-Sn phase. In thin films this phase transition is governed by the interplay between the vibrational behavior of the film (the phase transition is driven by the vibrational entropy) and the stabilizing influence of the substrate (which depends on the film thickness). This brings a deeper understanding of the role of lattice vibrations in the phase transition of nanoscale Sn.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000478992800005 Publication Date 2019-08-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 9 Open Access
Notes ; This work was supported by the Research Foundation Flanders (FWO) and the Concerted Research Action (Grant No. GOA14/007). K.H., S.C., D.P.L., and E.M. wish to thank the FWO for financial support. The authors gratefully acknowledge the European Synchrotron Radiation Facility (ESRF) for the granted beam time and the use of the in situ UHV preparation chamber. The authors thank B. Opperdoes for technical support and T. Peissker and R. Lieten for fruitful discussions. ; Approved Most recent IF: 3.836
Call Number UA @ admin @ c:irua:161836 Serial 5416
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Author Mirzakhani, M.; Peeters, F.M.; Zarenia, M.
Title Circular quantum dots in twisted bilayer graphene Type A1 Journal article
Year 2020 Publication Physical Review B Abbreviated Journal Phys Rev B
Volume 101 Issue (down) 7 Pages 075413
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Within a tight-binding approach, we investigate the effect of twisting angle on the energy levels of circular bilayer graphene (BLG) quantum dots (QDs) in both the absence and presence of a perpendicular magnetic field. The QDs are defined by an infinite-mass potential, so that the specific edge effects are not present. In the absence of magnetic field (or when the magnetic length is larger than the moire length), we show that the low-energy states in twisted BLG QDs are completely affected by the formation of moire patterns, with a strong localization at AA-stacked regions. When magnetic field increases, the energy gap of an untwisted BLG QD closes with the edge states, localized at the boundaries between the AA- and AB-stacked spots in a twisted BLG QD. Our observation of the spatial localization of the electrons in twisted BLG QDs can be experimentally probed by low-bias scanning tunneling microscopy measurements.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000512772200004 Publication Date 2020-02-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.7 Times cited 19 Open Access
Notes ; We gratefully acknowledge discussions with I. Snyman. M.Z. acknowledges support from the U.S. Department of Energy (Office of Science) under Grant No. DE-FG0205ER46203. ; Approved Most recent IF: 3.7; 2020 IF: 3.836
Call Number UA @ admin @ c:irua:166493 Serial 6470
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Author Nguyen, H.T.T.; Obeid, M.M.; Bafekry, A.; Idrees, M.; Vu, T.V.; Phuc, H., V; Hieu, N.N.; Le Hoa, T.; Amin, B.; Nguyen, C., V
Title Interfacial characteristics, Schottky contact, and optical performance of a graphene/Ga2SSe van der Waals heterostructure: Strain engineering and electric field tunability Type A1 Journal article
Year 2020 Publication Physical Review B Abbreviated Journal Phys Rev B
Volume 102 Issue (down) 7 Pages 075414-10
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Two-dimensional graphene-based van der Waals heterostructures have received considerable interest because of their intriguing characteristics compared with the constituent single-layer two-dimensional materials. Here, we investigate the interfacial characteristics, Schottky contact, and optical performance of graphene/Ga2SSe van der Waals (vdW) heterostructure using first-principles calculations. The effects of stacking patterns, electric gating, and interlayer coupling on the interfacial properties of graphene/Ga2SSe heterostructures are also examined. Our results demonstrate that the Dirac cone of graphene is well preserved at the F point in all stacking patterns due to the weak vdW interactions, which keep the heterostructures feasible such that they can be obtained in further experiments. Moreover, depending on the stacking patterns, a small band gap of about 13-17 meV opens in graphene and has a high carrier mobility, indicating that the graphene/Ga2SSe heterostructures are potential candidates for future high-speed nanoelectronic applications. In the ground state, the graphene/Ga2SSe heterostructures form an n-type Schottky contact. The transformation from an n-type to a p-type Schottky contact or to an Ohmic contact can be forced by electric gating or by varying the interlayer coupling. Our findings could provide physical guidance for designing controllable Schottky nanodevices with high electronic and optical performances.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000557294500006 Publication Date 2020-08-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.7 Times cited 12 Open Access
Notes ; This research is funded by Vietnam National Foundation for Science and Technology Development (NAFOSTED) under Grant No. 103.01-2019.05. The authors declare that there are no conflicts of interest regarding the publication of this paper. ; Approved Most recent IF: 3.7; 2020 IF: 3.836
Call Number UA @ admin @ c:irua:171163 Serial 6549
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Author Ahmadkhani, S.; Alihosseini, M.; Ghasemi, S.; Ahmadabadi, I.; Hassani, N.; Peeters, F.M.; Neek-Amal, M.
Title Multiband flattening and linear Dirac band structure in graphene with impurities Type A1 Journal article
Year 2023 Publication Physical review B Abbreviated Journal
Volume 107 Issue (down) 7 Pages 075401-75408
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Flat bands in the energy spectrum have attracted a lot of attention in recent years because of their unique properties and promising applications. Special arrangement of impurities on monolayer graphene are proposed to generate multiflat bands in the electronic band structure. In addition to the single midgap states in the spectrum of graphene with low hydrogen density, we found closely spaced bands around the Fermi level with increasing impurity density, which are similar to discrete lines in the spectrum of quantum dots, as well as the unusual Landau-level energy spectrum of graphene in the presence of a strong magnetic field. The presence of flat bands crucially depends on whether or not there are odd or even electrons of H(F) atoms bound to graphene. Interestingly, we found that a fully hydrogenated (fluoridated) of a hexagon of graphene sheet with six hydrogen (fluorine) atoms sitting on top and bottom in consecutive order exhibits Dirac cones in the electronic band structure with a 20% smaller Fermi velocity as compared to the pristine graphene. Functionalizing graphene introduces various C-C bond lengths resulting in nonuniform strains. Such a nonuniform strain may induce a giant pseudomagnetic field in the system, resulting in quantum Hall effect.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000994364500006 Publication Date 2023-02-02
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record
Impact Factor 3.7 Times cited 1 Open Access OpenAccess
Notes Approved Most recent IF: 3.7; 2023 IF: 3.836
Call Number UA @ admin @ c:irua:197431 Serial 8822
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Author Ghorbanfekr-Kalashami, H.; Peeters, F.M.; Novoselov, K.S.; Neek-Amal, M.
Title Spatial design and control of graphene flake motion Type A1 Journal article
Year 2017 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 96 Issue (down) 6 Pages 060101
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher American Physical Society Place of Publication New York, N.Y Editor
Language Wos 000406860300001 Publication Date 2017-08-04
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 3 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Methusalem program. M.N.-A. was supported by Iran National Science Foundation (INSF). K.S.N. was supported by the EU Graphene Flagship Program, European Research Council Synergy Grant Hetero2D, the Royal Society, Engineering and Physical Research Council (UK), US Army Research Office. ; Approved Most recent IF: 3.836
Call Number UA @ lucian @ c:irua:145166 Serial 4724
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Author Wang, W.; Van Duppen, B.; Van der Donck, M.; Peeters, F.M.
Title Magnetopolaron effect on shallow-impurity states in the presence of magnetic and intense terahertz laser fields in the Faraday configuration Type A1 Journal article
Year 2018 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 97 Issue (down) 6 Pages 064108
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The magnetopolaron effect on shallow-impurity states in semiconductors is investigated when subjected simultaneously to a magnetic field and an intense terahertz laser field within the Faraday configuration. We use a time-dependent nonperturbative theory to describe electron interactions. The externally applied fields are exactly included via a laser-dressed interaction potential. Through a variational approach we evaluate the binding energy of the shallow-impurity states. We find that the interaction strength of the laser-dressed Coulomb potential can not only be enhanced but also weakened by varying the two external fields. In this way, the binding energy can be tuned by the external fields and red-or blue-shifted with respect to the static binding energy. In the nonresonant polaron region, a magnetopolaron correction that includes the effects of photon process is observed. In the resonant polaron region, moreover, the resonant magnetopolaron effect accompanied by the emission and absorption of a single photon is distinctly observed. This can be modulated to be far away from the reststrahlen band. The intriguing findings of this paper can be observed experimentally and, in turn, provide a way to measure the strength of the electron-phonon interaction.
Address
Corporate Author Thesis
Publisher American Physical Society Place of Publication New York, N.Y Editor
Language Wos 000426041900004 Publication Date 2018-02-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 9 Open Access
Notes ; This work was supported by the National Natural Science Foundation of China (Grants No. 11404214 and No. 11455015) and the China Scholarship Council (CSC), Anhui Provincial Natural Science Foundation (Grant No. 1408085QA13), Key Projects of Anhui Provincial Department of Education (Grants No. KJ2017A406 and No. KJ2017A401). B.V.D. was financially supported by the Research Science Foundation-Flanders (FWO-Vl) through a postdoctoral fellowship and M.V.d.D. was financially supported by the Research Science Foundation-Flanders (FWO-Vl) through a doctoral fellowship. ; Approved Most recent IF: 3.836
Call Number UA @ lucian @ c:irua:149906UA @ admin @ c:irua:149906 Serial 4942
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Author Mulkers, J.; Hals, K.M.D.; Leliaert, J.; Milošević, M.V.; Van Waeyenberge, B.; Everschor-Sitte, K.
Title Effect of boundary-induced chirality on magnetic textures in thin films Type A1 Journal article
Year 2018 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 98 Issue (down) 6 Pages 064429
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract In the quest for miniaturizing magnetic devices, the effects of boundaries and surfaces become increasingly important. Here we show how the recently predicted boundary-induced Dzyaloshinskii-Moriya interaction (DMI) affects the magnetization of ferromagnetic films with a C-infinity v symmetry and a perpendicular magnetic anisotropy. For an otherwise uniformly magnetized film, we find a surface twist when the magnetization in the bulk is canted by an in-plane external field. This twist at the surfaces caused by the boundary-induced DMI differs from the common canting caused by internal DMI observed at the edges of a chiral magnet. Furthermore, we find that the surface twist due to the boundary-induced DMI strongly affects the width of the domain wall at the surfaces. We also find that the skyrmion radius increases in the depth of the film, with the average size of the skyrmion increasing with boundary-induced DMI. This increase suggests that the boundary-induced DMI contributes to the stability of the skyrmion.
Address
Corporate Author Thesis
Publisher American Physical Society Place of Publication New York, N.Y Editor
Language Wos 000443394600004 Publication Date 2018-08-31
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 9 Open Access
Notes ; The authors thank Matthias Sitte and Andre Thiaville for fruitful discussions. This work was supported by the Fonds Wetenschappelijk Onderzoek (FWO-Vlaanderen) through Project No. G098917N and the German Research Foundation (DFG) under the Project No. EV 196/2-1. J.L. is supported by the Ghent University Special Research Fund with a BOF postdoctoral fellowship. ; Approved Most recent IF: 3.836
Call Number UA @ lucian @ c:irua:153706UA @ admin @ c:irua:153706 Serial 5093
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Author Lozano, D.P.; Couet, S.; Petermann, C.; Hamoir, G.; Jochum, J.K.; Picot, T.; Menendez, E.; Houben, K.; Joly, V.; Antohe, V.A.; Hu, M.Y.; Leu, B.M.; Alatas, A.; Said, A.H.; Roelants, S.; Partoens, B.; Milošević, M.V.; Peeters, F.M.; Piraux, L.; Van de Vondel, J.; Vantomme, A.; Temst, K.; Van Bael, M.J.
Title Experimental observation of electron-phonon coupling enhancement in Sn nanowires caused by phonon confinement effects Type A1 Journal article
Year 2019 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 99 Issue (down) 6 Pages 064512
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Reducing the size of a superconductor below its characteristic length scales can either enhance or suppress its critical temperature (T-c). Depending on the bulk value of the electron-phonon coupling strength, electronic and phonon confinement effects will play different roles in the modification of T-c. Experimentally disentangling each contribution has remained a challenge. We have measured both the phonon density of states and T-c of Sn nanowires with diameters of 18, 35, and 100 nm in order to quantify the effects of phonon confinement on superconductivity. We observe a shift of the phonon frequency towards the low-energy region and an increase in the electron-phonon coupling constant that can account for the measured increase in T-c.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000459322400005 Publication Date 2019-02-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 11 Open Access
Notes ; We would like to thanks Jeroen Scheerder and Wout Keijers for their help and assistance during the low-temperature measurements. This work was supported by the Research Foundation Flanders (FWO), the Concerted Research Action (GOA/14/ 007), the Federation Wallonie-Bruxelles (ARC 13/18-052, Supracryst) and the Fonds de la Recherche Scientifique -FNRS under Grant No. T.0006.16. The authors acknowledge Hercules Stichting (Project Nos. AKUL/13/19 and AKUL/13/25). D.P.L. thanks the FWO for financial support. This research used resources of the Advanced Photon Source, a US Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. ; Approved Most recent IF: 3.836
Call Number UA @ admin @ c:irua:158621 Serial 5212
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Author Wang, J.; Andelkovic, M.; Wang, G.; Peeters, F.M.
Title Molecular collapse in graphene: Sublattice symmetry effect Type A1 Journal article
Year 2020 Publication Physical Review B Abbreviated Journal Phys Rev B
Volume 102 Issue (down) 6 Pages 064108-8
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Atomic collapse can be observed in graphene because of its large “effective” fine structure constant, which enables this phenomenon to occur for an impurity charge as low as Z(c) similar to 1-2. Here we investigate the effect of the sublattice symmetry on molecular collapse in two spatially separated charge tunable vacancies, which are located on the same (A-A type) or different (A-B type) sublattices. We find that the broken sublattice symmetry: (1) does not affect the location of the main bonding and antibonding molecular collapse peaks, (2) but shifts the position of the satellite peaks, because they are a consequence of the breaking of the local sublattice symmetry, and (3) there are vacancy characteristic collapse peaks that only occur for A-B type vacancies, which can be employed to distinguish them experimentally from the A-A type. As the charge, energy, and separation distance increase, the additional collapse features merge with the main molecular collapse peaks. We show that the spatial distribution around the vacancy site of the collapse states allows us to differentiate the molecular from the frustrated collapse.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000562320700002 Publication Date 2020-08-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.7 Times cited 3 Open Access
Notes ; This work was supported by the National Natural Science Foundation of China (Grants No. 61874038 and No. 61704040), National Key R&D Program Grant 2018YFE0120000, the scholarship from China Scholarship Council (CSC: 201908330548), and TRANS2DTMD FlagEra project. ; Approved Most recent IF: 3.7; 2020 IF: 3.836
Call Number UA @ admin @ c:irua:172065 Serial 6562
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Author Zhang, L.; Zhang, Y.-Y.; Zha, G.-Q.; Milošević, M.V.; Zhou, S.-P.
Title Skyrmionic chains and lattices in s plus id superconductors Type A1 Journal article
Year 2020 Publication Physical Review B Abbreviated Journal Phys Rev B
Volume 101 Issue (down) 6 Pages 064501
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We report characteristic vortex configurations in s + id superconductors with time-reversal symmetry breaking, exposed to magnetic field. A vortex in the s + id state tends to have an opposite phase winding between s- and d-wave condensates. We find that this peculiar feature together with the competition between s- and d-wave symmetry results in three distinct classes of vortical configurations. When either s or d condensate absolutely dominates, vortices form a conventional lattice. However, when one condensate is relatively dominant, vortices organize in chains that exhibit skyrmionic character, separating the chiral components of the s +/- id order parameter into domains within and outside the chain. Such skyrmionic chains are found stable even at high magnetic field. When s and d condensates have comparable strength, vortices split cores in two chiral components to form full-fledged skyrmions, i.e., coreless topological structures with an integer topological charge, organized in a lattice. We provide characteristic magnetic field distributions of all states, enabling their identification in, e.g., scanning Hall probe and scanning SQUID experiments. These unique vortex states are relevant for high-T-c cuprate and iron-based superconductors, where the relative strength of competing pairing symmetries is expected to be tuned by temperature and/or doping level, and can help distinguish s + is and s + id superconducting phases.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000510745600005 Publication Date 2020-02-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.7 Times cited 7 Open Access
Notes ; The authors acknowledge useful discussions with Yong-Ping Zhang. This research was supported by the National Natural Science Foundation of China under Grants No. 61571277 and No. 61771298. L.-F.Z. and M.V.M. acknowledge support from Research Foundation-Flanders (FWO-Vlaanderen). ; Approved Most recent IF: 3.7; 2020 IF: 3.836
Call Number UA @ admin @ c:irua:166507 Serial 6605
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Author Van der Donck, M.; Conti, S.; Perali, A.; Hamilton, A.R.; Partoens, B.; Peeters, F.M.; Neilson, D.
Title Three-dimensional electron-hole superfluidity in a superlattice close to room temperature Type A1 Journal article
Year 2020 Publication Physical Review B Abbreviated Journal Phys Rev B
Volume 102 Issue (down) 6 Pages 060503
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Although there is strong theoretical and experimental evidence for electron-hole superfluidity in separated sheets of electrons and holes at low T, extending superfluidity to high T is limited by strong two-dimensional fluctuations and Kosterlitz-Thouless effects. We show this limitation can be overcome using a superlattice of alternating electron- and hole-doped semiconductor monolayers. The superfluid transition in a three-dimensional superlattice is not topological, and for strong electron-hole pair coupling, the transition temperature T-c can be at room temperature. As a quantitative illustration, we show T-c can reach 270 K for a superfluid in a realistic superlattice of transition metal dichalcogenide monolayers.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000562320700001 Publication Date 2020-08-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.7 Times cited 8 Open Access
Notes ; This work was supported by the Research Foundation of Flanders (FWO-Vl) through an aspirant research grant for M.V.d.D., by the FLAG-ERA project TRANS-2D-TMD, and by the Australian Government through the Australian Research Council Centre of Excellence in Future Low-Energy Electronics (Project No. CE170100039). We thank Milorad V. Milossevi ' c, Pierbiagio Pieri, and Jacques Tempere for helpful discussions. ; Approved Most recent IF: 3.7; 2020 IF: 3.836
Call Number UA @ admin @ c:irua:172064 Serial 6628
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Author Vanderveken, F.; Mulkers, J.; Leliaert, J.; Van Waeyenberge, B.; Sorée, B.; Zografos, O.; Ciubotaru, F.; Adelmann, C.
Title Confined magnetoelastic waves in thin waveguides Type A1 Journal article
Year 2021 Publication Physical Review B Abbreviated Journal Phys Rev B
Volume 103 Issue (down) 5 Pages 054439
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The characteristics of confined magnetoelastic waves in nanoscale ferromagnetic magnetostrictive waveguides have been investigated by a combination of analytical and numerical calculations. The presence of both magnetostriction and inverse magnetostriction leads to the coupling between confined spin waves and elastic Lamb waves. Numerical simulations of the coupled system have been used to extract the dispersion relations of the magnetoelastic waves as well as their mode profiles.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000627548800003 Publication Date 2021-02-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited Open Access OpenAccess
Notes Approved Most recent IF: 3.836
Call Number UA @ admin @ c:irua:177607 Serial 6976
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Author Fernandez, M.S.; Peeters, F.M.; Neek-Amal, M.
Title Electric-field-induced structural changes in water confined between two graphene layers Type A1 Journal article
Year 2016 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 94 Issue (down) 4 Pages 045436
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract An external electric field changes the physical properties of polar liquids due to the reorientation of their permanent dipoles. Using molecular dynamics simulations, we predict that an in-plane electric field applied parallel to the channel polarizes water molecules which are confined between two graphene layers, resulting in distinct ferroelectricity and electrical hysteresis. We found that electric fields alter the in-plane order of the hydrogen bonds: Reversing the electric field does not restore the system to the nonpolar initial state, instead a residual dipole moment remains in the system. The square-rhombic structure of 2D ice is transformed into two rhombic-rhombic structures. Our study provides insights into the ferroelectric state of water when confined in nanochannels and shows how this can be tuned by an electric field.
Address
Corporate Author Thesis
Publisher American Physical Society Place of Publication New York, N.Y Editor
Language Wos 000381485200005 Publication Date 2016-07-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 31 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
Call Number UA @ lucian @ c:irua:144684 Serial 4649
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Author Lane, T.L.M.; Andelkovic, M.; Wallbank, J.R.; Covaci, L.; Peeters, F.M.; Fal'ko, V.I.
Title Ballistic electron channels including weakly protected topological states in delaminated bilayer graphene Type A1 Journal article
Year 2018 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 97 Issue (down) 4 Pages 045301
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract <script type='text/javascript'>document.write(unpmarked('We show that delaminations in bilayer graphene (BLG) with electrostatically induced interlayer symmetry can provide one with ballistic channels for electrons with energies inside the electrostatically induced BLG gap. These channels are formed by a combination of valley-polarized evanescent states propagating along the delamination edges (which persist in the presence of a strong magnetic field) and standing waves bouncing between them inside the delaminated region (in a strong magnetic field, these transform into Landau levels in the monolayers). For inverted stackings in BLGs on the left and right of the delamination (AB-2ML-BA or BA-2ML-AB, where 2ML indicates two decoupled monolayers of graphene), the lowest-energy ballistic channels are gapless, have linear dispersion, and appear to be weakly topologically protected. When BLG stackings on both sides of the delamination are the same (AB-2ML-AB or BA-2ML-BA), the lowest-energy ballistic channels are gapped, with a gap epsilon(g) scaling as epsilon(g) alpha W-1 with delamination width and epsilon(g) alpha delta(-1) with the on-layer energy difference in the delaminated part of the structure. Depending on the width, delaminations may also support several \u0022higher-energy\u0022 waveguide modes. Our results are based on both the analytical study of the wave matching of Dirac states and tight-binding model calculations, and we analyze in detail the dependence of the delamination spectrum on the electrostatic conditions in the structure, such as the vertical displacement field.'));
Address
Corporate Author Thesis
Publisher American Physical Society Place of Publication New York, N.Y Editor
Language Wos 000419772200005 Publication Date 2018-01-11
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 11 Open Access
Notes ; This work was funded by EPSRC via EPSRC Grand Engineering Chellenges Grant No. EP/N010345, the Manchester NOWNANO CDT EP/L-1548X, the Flemish Science Foundation (FWO-VI), the European Graphene Flagship project, ERC Synergy grant Hetero2D, and FLAG-ERA project TRANS2DTMD. The authors would like to acknowledge useful discussions with M. Zarenia, S. Slizovskiy, E. McCann, and K. Novesolov. ; Approved Most recent IF: 3.836
Call Number UA @ lucian @ c:irua:148441UA @ admin @ c:irua:148441 Serial 4868
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Author de de Meux, A.J.; Pourtois, G.; Genoe, J.; Heremans, P.
Title Method to quantify the delocalization of electronic states in amorphous semiconductors and its application to assessing charge carrier mobility of p-type amorphous oxide semiconductors Type A1 Journal article
Year 2018 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 97 Issue (down) 4 Pages 045208
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Amorphous semiconductors are usually characterized by a low charge carrier mobility, essentially related to their lack of long-range order. The development of such material with higher charge carrier mobility is hence challenging. Part of the issue comes from the difficulty encountered by first-principles simulations to evaluate concepts such as the electron effective mass for disordered systems since the absence of periodicity induced by the disorder precludes the use of common concepts derived from condensed matter physics. In this paper, we propose a methodology based on first-principles simulations that partially solves this problem, by quantifying the degree of delocalization of a wave function and of the connectivity between the atomic sites within this electronic state. We validate the robustness of the proposed formalism on crystalline and molecular systems and extend the insights gained to disordered/amorphous InGaZnO4 and Si. We also explore the properties of p-type oxide semiconductor candidates recently reported to have a low effective mass in their crystalline phases [G. Hautier et al., Nat. Commun. 4, 2292 (2013)]. Although in their amorphous phase none of the candidates present a valence band with delocalization properties matching those found in the conduction band of amorphous InGaZnO4, three of the seven analyzed materials show some potential. The most promising candidate, K2Sn2O3, is expected to possess in its amorphous phase a slightly higher hole mobility than the electron mobility in amorphous silicon.
Address
Corporate Author Thesis
Publisher American Physical Society Place of Publication New York, N.Y Editor
Language Wos 000423427600005 Publication Date 2018-01-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 2 Open Access OpenAccess
Notes Approved Most recent IF: 3.836
Call Number UA @ lucian @ c:irua:149318 Serial 4943
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Author Abdullah, H.M.; da Costa, D.R.; Bahlouli, H.; Chaves, A.; Peeters, F.M.; Van Duppen, B.
Title Electron collimation at van der Waals domain walls in bilayer graphene Type A1 Journal article
Year 2019 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 100 Issue (down) 4 Pages 045137
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We show that a domain wall separating single-layer graphene and AA-stacked bilayer graphene (AA-BLG) can be used to generate highly collimated electron beams which can be steered by a magnetic field. Two distinct configurations are studied, namely, locally delaminated AA-BLG and terminated AA-BLG whose terminal edge types are assumed to be either zigzag or armchair. We investigate the electron scattering using semiclassical dynamics and verify the results independently with wave-packet dynamics simulations. We find that the proposed system supports two distinct types of collimated beams that correspond to the lower and upper cones in AA-BLG. Our computational results also reveal that collimation is robust against the number of layers connected to AA-BLG and terminal edges.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000477892800005 Publication Date 2019-07-29
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 12 Open Access
Notes ; H.M.A. and H.B. acknowledge the support of King Fahd University of Petroleum and Minerals under research group Project No. RG181001. D.R.C and A.C. were financially supported by the Brazilian Council for Research (CNPq) and CAPES foundation. B.V.D. is supported by a postdoctoral fellowship by the Research Foundation Flanders (FWO-Vl). ; Approved Most recent IF: 3.836
Call Number UA @ admin @ c:irua:161887 Serial 5410
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Author Yagmurcukardes, M.; Sevik, C.; Peeters, F.M.
Title Electronic, vibrational, elastic, and piezoelectric properties of monolayer Janus MoSTe phases: A first-principles study Type A1 Journal article
Year 2019 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 100 Issue (down) 4 Pages 045415
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract By performing density functional theory based first-principles calculations, the electronic, vibrational, elastic, and piezoelectric properties of two dynamically stable crystal phases of monolayer Janus MoSTe, namely 1H-MoSTe and 1T'-MoSTe, are investigated. Vibrational frequency analysis reveals that the other possible crystal structure, 1T-MoSTe, of this Janus monolayer does not exhibit dynamical stability. The 1H-MoSTe phase is found to be an indirect band-gap semiconductor while 1T'-MoSTe is predicted as small-gap semiconductor. Notably, in contrast to the direct band-gap nature of monolayers 1H-MoS2 and 1H-MoTe2, 1H-MoSTe is found to be an indirect gap semiconductor driven by the induced surface strains on each side of the structure. The calculated Raman spectrum of each structure shows unique character enabling us to clearly distinguish the stable crystal phases via Raman measurements. The systematic piezoelectric stress and strain coefficient analysis reveals that out-of-plane piezoelectricity appears in 1H-MoSTe and the noncentral symmetric 1T'-MoSTe has large piezoelectric coefficients. Static total-energy calculations show clearly that the formation of 1T'-MoSTe is feasible by using 1T'-MoTe2 as a basis monolayer. Therefore, we propose that the Janus MoSTe structure can be fabricated in two dynamically stable phases which possess unique electronic, dynamical, and piezoelectric properties.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000476687800003 Publication Date 2019-07-19
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 128 Open Access
Notes ; Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure). This work was supported by the Flemish Science Foundation (FWO-Vl) by a postdoctoral fellowship (M.Y.). ; Approved Most recent IF: 3.836
Call Number UA @ admin @ c:irua:161899 Serial 5411
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Author Yagmurcukardes, M.; Mogulkoc, Y.; Akgenc, B.; Mogulkoc, A.; Peeters, F.M.
Title Prediction of monoclinic single-layer Janus Ga₂ Te X (X = S and Se) : strong in-plane anisotropy Type A1 Journal article
Year 2021 Publication Physical Review B Abbreviated Journal Phys Rev B
Volume 104 Issue (down) 4 Pages 045425
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract By using density functional theory (DFT) based first-principles calculations, electronic, vibrational, piezo-electric, and optical properties of monoclinic Janus single-layer Ga2TeX (X = S or Se) are investigated. The dynamical, mechanical, and thermal stability of the proposed Janus single layers are verified by means of phonon bands, stiffness tensor, and quantum molecular dynamics simulations. The calculated vibrational spectrum reveals the either pure or coupled optical phonon branches arising from Ga-Te and Ga-X atoms. In addition to the in-plane anisotropy, single-layer Janus Ga2TeX exhibits additional out-of-plane asymmetry, which leads to important consequences for its electronic and optical properties. Electronic band dispersions indicate the direct band-gap semiconducting nature of the constructed Janus structures with energy band gaps falling into visible spectrum. Moreover, while orientation-dependent linear-elastic properties of Janus single layers indicate their strong anisotropy, the calculated in-plane stiffness values reveal the ultrasoft nature of the structures. In addition, predicted piezoelectric coefficients show that while there is a strong in-plane anisotropy between piezoelectric constants along armchair (AC) and zigzag (ZZ) directions, there exists a tiny polarization along the out-of-plane direction as a result of the formation of Janus structure. The optical response to electromagnetic radiation has been also analyzed through density functional theory by considering the independent-particle approximation. Finally, the optical spectra of Janus Ga2TeX structures is investigated and it showed a shift from the ultraviolet region to the visible region. The fact that the spectrum is between these regions will allow it to be used in solar energy and many nanoelectronics applications. The predicted monoclinic single-layer Janus Ga2TeX are relevant for promising applications in optoelectronics, optical dichroism, and anisotropic nanoelasticity.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000678811100007 Publication Date 2021-07-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 14 Open Access Not_Open_Access
Notes Approved Most recent IF: 3.836
Call Number UA @ admin @ c:irua:180404 Serial 7013
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Author Shafiei, M.; Fazileh, F.; Peeters, F.M.; Milošević, M.V.
Title Tailoring weak and metallic phases in a strong topological insulator by strain and disorder : conductance fluctuations signatures Type A1 Journal article
Year 2024 Publication Physical review B Abbreviated Journal
Volume 109 Issue (down) 4 Pages 045129-7
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Transport measurements are readily used to probe different phases in disordered topological insulators (TIs), where determining topological invariants explicitly is challenging. On that note, universal conductance fluctuations (UCF) theory asserts the conductance G for an ensemble has a Gaussian distribution, and that standard deviation 8G depends solely on the symmetries and dimensions of the system. Using a real-space tight -binding Hamiltonian on a system with Anderson disorder, we explore conductance fluctuations in a thin Bi2Se3 film and demonstrate the agreement of their behavior with UCF hypotheses. We further show that magnetic field applied out-of-plane breaks the time -reversal symmetry and transforms the system's Wigner-Dyson class from root symplectic to unitary, increasing 8G by 2. Finally, we reveal that while Bi2Se3 is a strong TI, weak TI and metallic phases can be stabilized in presence of strain and disorder, and detected by monitoring the conductance fluctuations.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001173938400008 Publication Date 2024-01-16
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.7 Times cited 1 Open Access
Notes Approved Most recent IF: 3.7; 2024 IF: 3.836
Call Number UA @ admin @ c:irua:204765 Serial 9177
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Author Van der Donck, M.; Zarenia, M.; Peeters, F.M.
Title Excitons and trions in monolayer transition metal dichalcogenides : a comparative study between the multiband model and the quadratic single-band model Type A1 Journal article
Year 2017 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 96 Issue (down) 3 Pages 035131
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The electronic and structural properties of excitons and trions in monolayer transition metal dichalcogenides are investigated using both a multiband and a single- band model. In the multiband model we construct the excitonic Hamiltonian in the product base of the single-particle states at the conduction and valence band edges. We decouple the corresponding energy eigenvalue equation and solve the resulting differential equation self-consistently, using the finite element method (FEM), to determine the energy eigenvalues and the wave functions. As a comparison, we also consider the simple single-band model which is often used in numerical studies. We solve the energy eigenvalue equation using the FEM as well as with the stochastic variational method (SVM) in which a variational wave function is expanded in a basis of a large number of correlated Gaussians. We find good agreement between the results of both methods, as well as with other theoretical works for excitons, and we also compare with available experimental data. For trions the agreement between both methods is not as good due to our neglect of angular correlations when using the FEM. Finally, when comparing the two models, we see that the presence of the valence bands in the mutiband model leads to differences with the single- band model when (interband) interactions are strong.
Address
Corporate Author Thesis
Publisher American Physical Society Place of Publication New York, N.Y Editor
Language Wos 000405706600005 Publication Date 2017-07-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 50 Open Access
Notes ; This work was supported by the Research Foundation of Flanders (FWO-Vl) through an aspirant research grant for MVDD. ; Approved Most recent IF: 3.836
Call Number UA @ lucian @ c:irua:145209 Serial 4716
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Author Kong, X.; Li, L.; Leenaerts, O.; Liu, X.-J.; Peeters, F.M.
Title New group-V elemental bilayers : a tunable structure model with four-, six-, and eight-atom rings Type A1 Journal article
Year 2017 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 96 Issue (down) 3 Pages 035123
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Two-dimensional group-V elemental materials have attracted widespread attention due to their nonzero band gap while displaying high electron mobility. Using first-principles calculations, we propose a series of new elemental bilayers with group-V elements (Bi, Sb, As). Our study reveals the dynamical stability of four-, six-, and eight-atom ring structures, demonstrating their possible coexistence in such bilayer systems. The proposed structures for Sb and As are large-gap semiconductors that are potentially interesting for applications in future nanodevices. The Bi structures have nontrivial topological properties with a direct nontrivial band gap. The nontrivial gap is shown to arise from a band inversion at the Brillouin zone center due to the strong intrinsic spin-orbit coupling in Bi atoms. Moreover, we demonstrate the possibility of tuning the properties of these materials by enhancing the ratio of six-atom rings to four-and eight-atom rings, which results in wider nontrivial band gaps and lower formation energies.
Address
Corporate Author Thesis
Publisher American Physical Society Place of Publication New York, N.Y Editor
Language Wos 000405363900005 Publication Date 2017-07-14
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 14 Open Access
Notes ; This work is supported by Ministry of Science and Technology of China (MOST) (Grant No. 2016YFA0301604), National Natural Science Foundation of China (NSFC) ( No. 11574008), the Thousand-Young-Talent Program of China, and the Fonds voor Wetenschappelijk Onderzoek (FWO-Vl). The computational resources and services used in this work were provided by the VSC (Flemish Supercomputer Center), funded by the Research Foundation – Flanders (FWO) and the Flemish Government – department EWI, and the National Supercomputing Center in Tianjin, funded by the Collaborative Innovation Center of Quantum Matter. ; Approved Most recent IF: 3.836
Call Number UA @ lucian @ c:irua:144834 Serial 4721
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