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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 4 Pages 045425
  Keywords (up) 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
Permanent link to this record
 

 
Author Chaney, G.; Cakir, D.; Peeters, F.M.; Ataca, C.
  Title Stability of adsorption of Mg and Na on sulfur-functionalized MXenes Type A1 Journal article
  Year 2021 Publication Physical Chemistry Chemical Physics Abbreviated Journal Phys Chem Chem Phys
  Volume 23 Issue 44 Pages 25424-25433
  Keywords (up) A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Two-dimensional materials composed of transition metal carbides and nitrides (MXenes) are poised to revolutionize energy conversion and storage. In this work, we used density functional theory (DFT) to investigate the adsorption of Mg and Na adatoms on five M2CS2 monolayers (where M = Mo, Nb, Ti, V, and Zr) for battery applications. We assessed the stability of the adatom (i.e. Na and Mg)-monolayer systems by calculating adsorption and formation energies, as well as voltages as a function of surface coverage. For instance, we found that Mo2CS2 cannot support a full layer of Na nor even a single Mg atom. Na and Mg exhibit the strongest binding on Zr2CS2, followed by Ti2CS2, Nb2CS2 and V2CS2. Using the nudged elastic band method (NEB), we computed promising diffusion barriers for both dilute and nearly full ion surface coverage cases. In the dilute ion adsorption case, a single Mg and Na atom on Ti2CS2 experience similar to 0.47 eV and similar to 0.10 eV diffusion barriers between the lowest energy sites, respectively. For a nearly full surface coverage, a Na ion moving on Ti2CS2 experiences a similar to 0.33 eV energy barrier, implying a concentration-dependent diffusion barrier. Our molecular dynamics results indicate that the three (one) layers (layer) of the Mg (Na) ion on both surfaces of Ti2CS2 remain stable at T = 300 K. While, according to voltage calculations, Zr2CS2 can store Na up to three atomic layers, our MD simulations predict that the outermost layers detach from the Zr2CS2 monolayer due to the weak interaction between Na ions and the monolayer. This suggests that MD simulations are essential to confirm the stability of an ion-electrode system – an insight that is mostly absent in previous studies.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000716024400001 Publication Date 2021-10-22
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1463-9076; 1463-9084 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 4.123 Times cited 7 Open Access Not_Open_Access
  Notes Approved Most recent IF: 4.123
  Call Number UA @ admin @ c:irua:184075 Serial 7020
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Author Nazar, N.D.; Vazifehshenas, T.; Ebrahimi, M.R.; Peeters, F.M.
  Title Strong anisotropic optical properties of 8-Pmmn borophene : a many-body perturbation study Type A1 Journal article
  Year 2021 Publication Physical Chemistry Chemical Physics Abbreviated Journal Phys Chem Chem Phys
  Volume 23 Issue 30 Pages 16417-16422
  Keywords (up) A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Using first-principles many-body perturbation theory, we investigate the optical properties of 8-Pmmn borophene at two levels of approximations; the GW method considering only the electron-electron interaction and the GW in combination with the Bethe-Salpeter equation including electron-hole coupling. The band structure exhibits anisotropic Dirac cones with semimetallic character. The optical absorption spectra are obtained for different light polarizations and we predict strong optical absorbance anisotropy. The absorption peaks undergo a global redshift when the electron-hole interaction is taken into account due to the formation of bound excitons which have an anisotropic excitonic wave function.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000677722700001 Publication Date 2021-07-21
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1463-9076; 1463-9084 ISBN Additional Links UA library record; WoS full record
  Impact Factor 4.123 Times cited 4 Open Access Not_Open_Access
  Notes Approved Most recent IF: 4.123
  Call Number UA @ admin @ c:irua:180385 Serial 7022
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Author Dong, H.M.; Tao, Z.H.; Duan, Y.F.; Li, L.L.; Huang, F.; Peeters, F.M.
  Title Substrate dependent terahertz magneto-optical properties of monolayer WS2 Type A1 Journal article
  Year 2021 Publication Optics Letters Abbreviated Journal Opt Lett
  Volume 46 Issue 19 Pages 4892-4895
  Keywords (up) A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Terahertz (THz) magneto-optical (MO) properties of monolayer (ML) tungsten disulfide (WS2), placed on different substrates and subjected to external magnetic fields, are studied using THz time-domain spectroscopy (TDS). We find that the THz MO conductivity exhibits a nearly linear response in a weak magnetic field, while a distinctly nonlinear/oscillating behavior is found in strong magnetic fields owing to strong substrate-induced random impurity scattering and interactions. The THz MO response of ML WS2 depends sensitively on the choice of the substrates, which we trace back to electronic localization and the impact of the substrates on the Landau level (LL) spectrum. Our results provide an in-depth understanding of the THz MO properties of ML WS2/substrate systems, especially the effect of substrates, which can be utilized to realize atomically thin THz MO nano-devices. (C) 2021 Optical Society of America
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000702746400048 Publication Date 2021-09-01
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0146-9592 ISBN Additional Links UA library record; WoS full record
  Impact Factor 3.416 Times cited 2 Open Access OpenAccess
  Notes Approved Most recent IF: 3.416
  Call Number UA @ admin @ c:irua:182526 Serial 7023
Permanent link to this record
 

 
Author Tao, Z.H.; Dong, H.M.; Milošević, M.V.; Peeters, F.M.; Van Duppen, B.
  Title Tailoring dirac plasmons via anisotropic dielectric environment by design Type A1 Journal article
  Year 2021 Publication Physical Review Applied Abbreviated Journal Phys Rev Appl
  Volume 16 Issue 5 Pages 054030
  Keywords (up) A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Dirac plasmons in a two-dimensional (2D) crystal are strongly affected by the dielectric properties of the environment, due to interaction of their electric field lines with the surrounding medium. Using graphene as a 2D reservoir of free carriers, one can engineer a material configuration that provides an anisotropic environment to the plasmons. In this work, we discuss the physical properties of Dirac plasmons in graphene surrounded by an arbitrary anisotropic dielectric and exemplify how h-BN-based heterostructures can be designed to bear the required anisotropic characteristics. We calculate how dielec-tric anisotropy impacts the spatial propagation of the plasmons and find that an anisotropy-induced plasmon mode emerges, together with a damping pathway, that stem from the out-of-plane off-diagonal elements in the dielectric tensor. Furthermore, we find that one can create hyperbolic plasmons by inher-iting the dielectric hyperbolicity of the designed material environment. Strong control over plasmon propagation patterns can be realized in a similar manner. Finally, we show that in this way one can also control the polarization of the light-matter excitations that constitute the plasmon. Taken together, our results promote the design of the dielectric environment as an effective path to tailor the plasmonic response of graphene on the nanoscopic level.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000720372500002 Publication Date 2021-11-15
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 2331-7019 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 4.808 Times cited 2 Open Access Not_Open_Access
  Notes Approved Most recent IF: 4.808
  Call Number UA @ admin @ c:irua:184063 Serial 7028
Permanent link to this record
 

 
Author Man, L.F.; Xu, W.; Xiao, Y.M.; Wen, H.; Ding, L.; Van Duppen, B.; Peeters, F.M.
  Title Terahertz magneto-optical properties of graphene hydrodynamic electron liquid Type A1 Journal article
  Year 2021 Publication Physical Review B Abbreviated Journal Phys Rev B
  Volume 104 Issue 12 Pages 125420
  Keywords (up) A1 Journal article; Condensed Matter Theory (CMT)
  Abstract The discovery of the hydrodynamic electron liquid (HEL) in graphene [D. Bandurin et al., Science 351, 1055 (2016) and J. Crossno et al., Science 351, 1058 (2016)] has marked the birth of the solid-state HEL which can be probed near room temperature in a table-top setup. Here we examine the terahertz (THz) magneto-optical (MO) properties of a graphene HEL. Considering the case where the magnetic length l(B) = root h/eB is comparable to the mean-free path l(ee) for electron-electron interaction in graphene, the MO conductivities are obtained by taking a momentum balance equation approach on the basis of the Boltzmann equation. We find that when l(B) similar to l(ee), the viscous effect in a HEL can weaken significantly the THz MO effects such as cyclotron resonance and Faraday rotation. The upper hybrid and cyclotron resonance magnetoplasmon modes omega(+/-) are also obtained through the RPA dielectric function. The magnetoplasmons of graphene HEL at large wave-vector regime are affected by the viscous effect, and results in red-shifts of the magnetoplasmon frequencies. We predict that the viscosity in graphene HEL can affect strongly the magneto-optical and magnetoplasmonic properties, which can be verified experimentally.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000704419300004 Publication Date 2021-09-15
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 3.836 Times cited 4 Open Access OpenAccess
  Notes Approved Most recent IF: 3.836
  Call Number UA @ admin @ c:irua:182518 Serial 7029
Permanent link to this record
 

 
Author Chen, Q.; Guo, A.-M.; Liu, J.; Peeters, F.M.; Sun, Q.-F.
  Title Topological phase transitions and Majorana zero modes in DNA double helix coupled to s-wave superconductors Type A1 Journal article
  Year 2021 Publication New Journal Of Physics Abbreviated Journal New J Phys
  Volume 23 Issue 9 Pages 093047
  Keywords (up) A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Topological properties of a double-stranded DNA (dsDNA) proximity-coupled by an s-wave superconductor are investigated, in which the energy spectra and the differential conductance are calculated within the framework of tight-binding approximation. Our results indicate that this dsDNA-superconductor system hosts Majorana zero modes (MZMs) when the Zeeman field is perpendicular to the helix axis, whereas no MZM could be observed when the Zeeman field is parallel to the helix axis, in sharp contrast to previous studies on nanowires including single-stranded DNA. In particular, two topological phase transitions could take place in the dsDNA-superconductor system by changing the Zeeman field, one from a topological trivial phase to a topological nontrivial phase with one pair of MZMs in small Zeeman field regime, and the other from a phase with one pair of MZMs to a phase with two pairs of MZMs by further increasing the Zeeman field. In the presence of a gate field normal to the helix axis, the topological nontrivial phase with two pairs of MZMs can transform into the phase with one pair of MZMs. The topological phase with one pair of MZMs is more stable and robust against Anderson disorder.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000702122000001 Publication Date 2021-09-15
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1367-2630 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 3.786 Times cited 7 Open Access OpenAccess
  Notes Approved Most recent IF: 3.786
  Call Number UA @ admin @ c:irua:182597 Serial 7033
Permanent link to this record
 

 
Author Lavor, I.R.; Chaves, A.; Peeters, F.M.; Van Duppen, B.
  Title Tunable coupling of terahertz Dirac plasmons and phonons in transition metal dichalcogenide-based van der Waals heterostructures Type A1 Journal article
  Year 2021 Publication 2d Materials Abbreviated Journal 2D Mater
  Volume Issue Pages 015018
  Keywords (up) A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Dirac plasmons in graphene hybridize with phonons of transition metal dichalcogenides (TMDs) when the materials are combined in so-called van der Waals heterostructures (vdWh), thus forming surface plasmon-phonon polaritons (SPPPs). The extend to which these modes are coupled depends on the TMD composition and structure, but also on the plasmons' properties. By performing realistic simulations that account for the contribution of each layer of the vdWh separately, we calculate how the strength of plasmon-phonon coupling depends on the number and composition of TMD layers, on the graphene Fermi energy and the specific phonon mode. From this, we present a semiclassical theory that is capable of capturing all relevant characteristics of the SPPPs. We find that it is possible to realize both strong and ultra-strong coupling regimes by tuning graphene's Fermi energy and changing TMD layer number.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000722020100001 Publication Date 2021-11-08
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 2053-1583 ISBN Additional Links UA library record; WoS full record
  Impact Factor 6.937 Times cited 1 Open Access OpenAccess
  Notes Approved Most recent IF: 6.937
  Call Number UA @ admin @ c:irua:183053 Serial 7036
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Author Chaves, A.; Peeters, F.M.
  Title Tunable effective masses of magneto-excitons in two-dimensional materials Type A1 Journal article
  Year 2021 Publication Solid State Communications Abbreviated Journal Solid State Commun
  Volume 334 Issue Pages 114371
  Keywords (up) A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Excitonic properties of Ge2H2 and Sn2H2, also known as Xanes, are investigated within the effective mass model. A perpendicularly applied magnetic field induces a negative shift on the exciton center-of-mass kinetic energy that is approximately quadratic with its momentum, thus pushing down the exciton dispersion curve and flattening it. This can be interpreted as an increase in the effective mass of the magneto-exciton, tunable by the field intensity. Our results show that in low effective mass two-dimensional semiconductors, such as Xanes, the applied magnetic field allows one to tune the magneto-exciton effective mass over a wide range of values.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000670329600003 Publication Date 2021-05-14
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0038-1098 ISBN Additional Links UA library record; WoS full record
  Impact Factor 1.554 Times cited Open Access Not_Open_Access
  Notes Approved Most recent IF: 1.554
  Call Number UA @ admin @ c:irua:179762 Serial 7037
Permanent link to this record
 

 
Author Dehdast, M.; Valiollahi, Z.; Neek-Amal, M.; Van Duppen, B.; Peeters, F.M.; Pourfath, M.
  Title Tunable natural terahertz and mid-infrared hyperbolic plasmons in carbon phosphide Type A1 Journal article
  Year 2021 Publication Carbon Abbreviated Journal Carbon
  Volume 178 Issue Pages 625-631
  Keywords (up) A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Hyperbolic polaritons in ultra thin materials such as few layers of van derWaals heterostructures provide a unique control over light-matter interaction at the nanoscale and with various applications in flat optics. Natural hyperbolic surface plasmons have been observed on thin films of WTe2 in the light wavelength range of 16-23 mu m (similar or equal to 13-18 THz) [Nat. Commun. 11, 1158 (2020)]. Using time-dependent density functional theory, it is found that carbon doped monolayer phosphorene (beta-allotrope of carbon phosphide monolayer) exhibits natural hyperbolic plasmons at frequencies above similar or equal to 5 THz which is not observed in its parent materials, i.e. monolayer of black phosphorous and graphene. Furthermore, we found that by electrostatic doping the plasmonic frequency range can be extended to the mid-infrared. (C) 2021 Elsevier Ltd. All rights reserved.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000648729800057 Publication Date 2021-03-26
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0008-6223 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 6.337 Times cited 11 Open Access Not_Open_Access
  Notes Approved Most recent IF: 6.337
  Call Number UA @ admin @ c:irua:179033 Serial 7039
Permanent link to this record
 

 
Author Baskurt, M.; Nair, R.R.; Peeters, F.M.; Sahin, H.
  Title Ultra-thin structures of manganese fluorides : conversion from manganese dichalcogenides by fluorination Type A1 Journal article
  Year 2021 Publication Physical Chemistry Chemical Physics Abbreviated Journal Phys Chem Chem Phys
  Volume 23 Issue 17 Pages 10218-10224
  Keywords (up) A1 Journal article; Condensed Matter Theory (CMT)
  Abstract In this study, it is predicted by density functional theory calculations that graphene-like novel ultra-thin phases of manganese fluoride crystals, that have nonlayered structures in their bulk form, can be stabilized by fluorination of manganese dichalcogenide crystals. First, it is shown that substitution of fluorine atoms with chalcogens in the manganese dichalcogenide host lattice is favorable. Among possible crystal formations, three stable ultra-thin structures of manganese fluoride, 1H-MnF2, 1T-MnF2 and MnF3, are found to be stable by total energy optimization calculations. In addition, phonon calculations and Raman activity analysis reveal that predicted novel single-layers are dynamically stable crystal structures displaying distinctive characteristic peaks in their vibrational spectrum enabling experimental determination of the corresponding phases. Differing from 1H-MnF2 antiferromagnetic (AFM) large gap semiconductor, 1T-MnF2 and MnF3 single-layers are semiconductors with ferromagnetic (FM) ground state.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000641719700001 Publication Date 2021-04-15
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1463-9076; 1463-9084 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 4.123 Times cited 1 Open Access Not_Open_Access
  Notes Approved Most recent IF: 4.123
  Call Number UA @ admin @ c:irua:178252 Serial 7043
Permanent link to this record
 

 
Author Zhang, H.Y.; Xiao, Y.M.; N. Li, Q.; Ding, L.; Van Duppen, B.; Xu, W.; Peeters, F.M.
  Title Anisotropic and tunable optical conductivity of a two-dimensional semi-Dirac system in the presence of elliptically polarized radiation Type A1 Journal article
  Year 2022 Publication Physical review B Abbreviated Journal Phys Rev B
  Volume 105 Issue 11 Pages 115423-115429
  Keywords (up) A1 Journal article; Condensed Matter Theory (CMT)
  Abstract We investigate the effect of ellipticity ratio of the polarized radiation field on optoelectronic properties of a two-dimensional (2D) semi-Dirac (SD) system. The optical conductivity is calculated within the energy balance equation approach derived from the semiclassical Boltzmann equation. We find that there exists the anisotropic optical absorption induced via both the intra-and interband electronic transition channels in the perpendicular xx and yy directions. Furthermore, we examine the effects of the ellipticity ratio, the temperature, the carrier density, and the band-gap parameter on the optical conductivity of the 2D SD system placed in transverse and vertical directions, respectively. It is shown that the ellipticity ratio, temperature, carrier density, and band-gap parameter can play the important roles in tuning the strength, peak position, and shape of the optical conductivity spectrum. The results obtained from this study indicate that the 2D SD system can be a promising anisotropic and tunable optical and optoelectronic material for applications in innovative 2D optical and optoelectronic devices, which are active in the infrared and terahertz bandwidths.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000802810700002 Publication Date 2022-03-22
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 3.7 Times cited 3 Open Access OpenAccess
  Notes Approved Most recent IF: 3.7
  Call Number UA @ admin @ c:irua:188660 Serial 7125
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Author Yagmurcukardes, N.; Bayram, A.; Aydin, H.; Yagmurcukardes, M.; Acikbas, Y.; Peeters, F.M.; Celebi, C.
  Title Anisotropic etching of CVD grown graphene for ammonia sensing Type A1 Journal article
  Year 2022 Publication IEEE sensors journal Abbreviated Journal Ieee Sens J
  Volume 22 Issue 5 Pages 3888-3895
  Keywords (up) A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Bare chemical vapor deposition (CVD) grown graphene (GRP) was anisotropically etched with various etching parameters. The morphological and structural characterizations were carried out by optical microscopy and the vibrational properties substrates were obtained by Raman spectroscopy. The ammonia adsorption and desorption behavior of graphene-based sensors were recorded via quartz crystal microbalance (QCM) measurements at room temperature. The etched samples for ambient NH3 exhibited nearly 35% improvement and showed high resistance to humidity molecules when compared to bare graphene. Besides exhibiting promising sensitivity to NH3 molecules, the etched graphene-based sensors were less affected by humidity. The experimental results were collaborated by Density Functional Theory (DFT) calculations and it was shown that while water molecules fragmented into H and O, NH3 interacts weakly with EGPR2 sample which reveals the enhanced sensing ability of EGPR2. Apparently, it would be more suitable to use EGRP2 in sensing applications due to its sensitivity to NH3 molecules, its stability, and its resistance to H2O molecules in humid ambient.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000766276000010 Publication Date 2022-01-24
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1530-437x; 1558-1748 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 4.3 Times cited 4 Open Access Not_Open_Access
  Notes Approved Most recent IF: 4.3
  Call Number UA @ admin @ c:irua:187257 Serial 7126
Permanent link to this record
 

 
Author Shafiei, M.; Fazileh, F.; Peeters, F.M.; Milošević, M.V.
  Title Axion insulator states in a topological insulator proximitized to magnetic insulators : a tight-binding characterization Type A1 Journal article
  Year 2022 Publication Physical review materials Abbreviated Journal
  Volume 6 Issue 7 Pages 074205-74208
  Keywords (up) A1 Journal article; Condensed Matter Theory (CMT)
  Abstract The recent discovery of axion states in materials such as antiferromagnetic topological insulators has boosted investigations of the magnetoelectric response in topological insulators and their promise towards realizing dissipationless topological electronics. In this paper, we develop a tight-binding methodology to explore the emergence of axion states in Bi2Se3 in proximity to magnetic insulators on the top and bottom surfaces. The topological protection of the surface states is lifted by a time-reversal-breaking perturbation due to the proximity of a magnetic insulator, and a gap is opened on the surfaces, giving rise to half-quantized Hall conductance and a zero Hall plateau-evidencing an axion insulator state. We developed a real-space tight-binding Hamiltonian for Bi2Se3 using first-principles data. Transport properties of the system were obtained within the Landauer-Buttiker formalism, and we discuss the creation of axion states through Hall conductance and a zero Hall plateau at the surfaces, as a function of proximitized magnetization and corresponding potentials at the surfaces, as well as the thickness of the topological insulator.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000832387000006 Publication Date 2022-07-21
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 2475-9953 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 3.4 Times cited 4 Open Access OpenAccess
  Notes Approved Most recent IF: 3.4
  Call Number UA @ admin @ c:irua:189498 Serial 7130
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Author Shafiei, M.; Fazileh, F.; Peeters, F.M.; Milošević, M.V.
  Title Controlling the hybridization gap and transport in a thin-film topological insulator : effect of strain, and electric and magnetic field Type A1 Journal article
  Year 2022 Publication Physical review B Abbreviated Journal Phys Rev B
  Volume 106 Issue 3 Pages 035119-7
  Keywords (up) A1 Journal article; Condensed Matter Theory (CMT)
  Abstract In a thin-film topological insulator (TI), the edge states on two surfaces may couple by quantum tunneling, opening a gap known as the hybridization gap. Controlling the hybridization gap and transport has a variety of potential uses in photodetection and energy-harvesting applications. In this paper, we report the effect of strain, and electric and magnetic field, on the hybridization gap and transport in a thin Bi2Se3 film, investigated within the tight-binding theoretical framework. We demonstrate that vertical compression decreases the hybridization gap, as does tensile in-plane strain. Applying an electric field breaks the inversion symmetry and leads to a Rashba-like spin splitting proportional to the electric field, hence closing and reopening the gap. The influence of a magnetic field on thin-film TI is also discussed, starting from the role of an out-of-plane magnetic field on quantum Hall states. We further demonstrate that the hybridization gap can be controlled by an in-plane magnetic field, and that by applying a sufficiently strong field a quantum phase transition from an insulator to a semimetal can be achieved.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000832277500001 Publication Date 2022-07-13
  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 7 Open Access Not_Open_Access
  Notes Approved Most recent IF: 3.7
  Call Number UA @ admin @ c:irua:189515 Serial 7140
Permanent link to this record
 

 
Author Mirzakhani, M.; da Costa, D.R.; Peeters, F.M.
  Title Isolated and hybrid bilayer graphene quantum rings Type A1 Journal article
  Year 2022 Publication Physical review B Abbreviated Journal Phys Rev B
  Volume 105 Issue 11 Pages 115430-11
  Keywords (up) A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Using the continuum model, we investigate the electronic properties of two types of bilayer graphene (BLG) quantum ring (QR) geometries: (i) An isolated BLG QR and (ii) a monolayer graphene (MLG) with a QR put on top of an infinite graphene sheet (hybrid BLG QR). Solving the Dirac-Weyl equation in the presence of a perpendicular magnetic field and applying the infinite mass boundary condition at the ring boundaries, we obtain analytical results for the energy levels and corresponding wave spinors for both structures. In the case of isolated BLG QR, we observe a sizable and magnetically tunable band gap which agrees with the tight-binding transport simulations. Our analytical results also show the intervalley symmetry EeK (m) = ???EK??? h (m) between the electron (e) and the hole (h) states (m is the angular momentum quantum number) for the energy spectrum of the isolated BLG QR. The presence of interface boundary in a hybrid BLG QR modifies drastically the energy levels as compared with that of an isolated BLG QR. Its energy levels are tunable from MLG dot to isolated BLG QR and to MLG Landau energy levels as the magnetic field is varied. Our predictions can be verified experimentally using different techniques such as by magnetotransport measurements.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000801209300006 Publication Date 2022-03-28
  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 4 Open Access OpenAccess
  Notes Approved Most recent IF: 3.7
  Call Number UA @ admin @ c:irua:188703 Serial 7175
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Author Cunha, S.M.; da Costa, D.R.; Pereira, J.M., Jr.; Costa Filho, R.N.; Van Duppen, B.; Peeters, F.M.
  Title Tunneling properties in α-T₃ lattices : effects of symmetry-breaking terms Type A1 Journal article
  Year 2022 Publication Physical review B Abbreviated Journal Phys Rev B
  Volume 105 Issue 16 Pages 165402-165414
  Keywords (up) A1 Journal article; Condensed Matter Theory (CMT)
  Abstract The alpha-T3 lattice model interpolates a honeycomb (graphene-like) lattice and a T3 (also known as dice) lattice via the parameter alpha. These lattices are made up of three atoms per unit cell. This gives rise to an additional dispersionless flat band touching the conduction and valence bands. Electrons in this model are analogous to Dirac fermions with an enlarged pseudospin, which provides unusual tunneling features like omnidirectional Klein tunneling, also called super-Klein tunneling (SKT). However, it is unknown how small deviations in the equivalence between the atomic sites, i.e., variations in the alpha parameter, and the number of tunnel barriers changes the transmission properties. Moreover, it is interesting to learn how tunneling occurs through regions where the energy spectrum changes from linear with a middle flat band to a hyperbolic dispersion. In this paper we investigate these properties, its dependence on the number of square barriers and the alpha parameter for either gapped and gapless cases. Furthermore, we compare these results to the case where electrons tunnel from a region with linear dispersion to a region with a bandgap. In the latter case, contrary to tunneling through a potential barrier, the SKT is no longer observed. Finally, we find specific cases where transmission is allowed due to a symmetry breaking of sublattice equivalence.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000805195200001 Publication Date 2022-04-01
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 3.7 Times cited Open Access OpenAccess
  Notes Approved Most recent IF: 3.7
  Call Number UA @ admin @ c:irua:188614 Serial 7222
Permanent link to this record
 

 
Author Yu, Y.; Xie, X.; Liu, X.; Li, J.; Peeters, F.M.; Li, L.
  Title Two-dimensional semimetal states in transition metal trichlorides : a first-principles study Type A1 Journal article
  Year 2022 Publication Applied physics letters Abbreviated Journal Appl Phys Lett
  Volume 121 Issue 11 Pages 112405-112407
  Keywords (up) A1 Journal article; Condensed Matter Theory (CMT)
  Abstract The two-dimensional (2D) transition metal trihalide (TMX3, X = Cl, Br, I) family has attracted considerable attention in recent years due to the realization of CrCl3, CrBr3, and CrI3 monolayers. Up to now, the main focus of the theoretically predicted TMX3 monolayers has been on the Chern insulator states, which can realize the quantum anomalous Hall effect. Here, using first-principles calculations, we theoretically demonstrate that the stable OsCl3 monolayer has a ferromagnetic ground state and a spin-polarized Dirac point without spin-orbit coupling (SOC), which disappears in the band structure of a Janus OsBr1.5Cl1.5 monolayer. We find that OsCl3 exhibits in-plane magnetization when SOC is included. By manipulating the magnetization direction along the C-2 symmetry axis of the OsCl3 structure, a gapless half-Dirac semimetal state with SOC can be achieved, which is different from the gapped Chern insulator state. Both semimetal states of OsCl3 monolayer without and with SOC exhibit a linear half-Dirac point (twofold degenerate) with high Fermi velocities. The achievement of the 2D semimetal state with SOC is expected to be found in other TMX3 monolayers, and we confirm it in a TiCl3 monolayer. This provides a different perspective to study the band structure with SOC of the 2D TMX3 family.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000863219400003 Publication Date 2022-09-15
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0003-6951; 1077-3118 ISBN Additional Links UA library record; WoS full record
  Impact Factor 4 Times cited 4 Open Access OpenAccess
  Notes Approved Most recent IF: 4
  Call Number UA @ admin @ c:irua:191541 Serial 7223
Permanent link to this record
 

 
Author Mirzakhani, M.; Myoung, N.; Peeters, F.M.; Park, H.C.
  Title Electronic Mach-Zehnder interference in a bipolar hybrid monolayer-bilayer graphene junction Type A1 Journal article
  Year 2023 Publication Carbon Abbreviated Journal
  Volume 201 Issue Pages 734-744
  Keywords (up) A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Graphene matter in a strong magnetic field, realizing one-dimensional quantum Hall channels, provides a unique platform for studying electron interference. Here, using the Landauer-Buttiker formalism along with the tightbinding model, we investigate the quantum Hall (QH) effects in unipolar and bipolar monolayer-bilayer graphene (MLG-BLG) junctions. We find that a Hall bar made of an armchair MLG-BLG junction in the bipolar regime results in valley-polarized edgechannel interferences and can operate a fully tunable Mach-Zehnder (MZ) interferometer device. Investigation of the bar-width and magnetic-field dependence of the conductance oscillations shows that the MZ interference in such structures can be drastically affected by the type of (zigzag) edge termination of the second layer in the BLG region [composed of vertical dimer or non-dimer atoms]. Our findings reveal that both interfaces exhibit a double set of Aharonov-Bohm interferences, with the one between two oppositely valley-polarized edge channels dominating and causing a large amplitude conductance oscillation ranging from 0 to 2e2/h. We explain and analyze our findings by analytically solving the Dirac-Weyl equation for a gated semi-infinite MLG-BLG junction.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000868911500004 Publication Date 2022-09-28
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0008-6223 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 10.9 Times cited 3 Open Access Not_Open_Access
  Notes Approved Most recent IF: 10.9; 2023 IF: 6.337
  Call Number UA @ admin @ c:irua:191516 Serial 7302
Permanent link to this record
 

 
Author Jiang, J.; Milošević, M.V.; Wang, Y.-L.; Xiao, Z.-L.; Peeters, F.M.; Chen, Q.-H.
  Title Field-free superconducting diode in a magnetically nanostructured superconductor Type A1 Journal article
  Year 2022 Publication Physical review applied Abbreviated Journal Phys Rev Appl
  Volume 18 Issue 3 Pages 034064-34069
  Keywords (up) A1 Journal article; Condensed Matter Theory (CMT)
  Abstract A strong superconducting diode effect (SDE) is revealed in a thin superconducting film periodically nanostructured with magnetic dots. The SDE is caused by the current-activated dissipation mitigated by vortex-antivortex pairs (VAPs), which periodically nucleate under the dots, move and annihilate in the superconductor-eventually driving the system to the high-resistive state. Inversing the polarity of the applied current destimulates the nucleation of VAPs, the system remains superconducting up to far larger currents, leading to the pronounced diodic response. Our dissipative Ginzburg-Landau simulations detail the involved processes, and provide reliable geometric and parametric ranges for the experimental realiza-tion of such a nonvolatile superconducting diode, which operates in the absence of any applied magnetic field while being fluxonic by design.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000870234200001 Publication Date 2022-09-23
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 2331-7019 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 4.6 Times cited 9 Open Access OpenAccess
  Notes Approved Most recent IF: 4.6
  Call Number UA @ admin @ c:irua:191539 Serial 7307
Permanent link to this record
 

 
Author Mirzakhani, M.; Zarenia, M.; Vasilopoulos, P.; Peeters, F.M.
  Title Electrostatically confined trilayer graphene quantum dots Type A1 Journal article
  Year 2017 Publication Physical review B Abbreviated Journal
  Volume 95 Issue 15 Pages 155434
  Keywords (up) A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Electrically gating of trilayer graphene (TLG) opens a band gap offering the possibility to electrically engineer TLG quantum dots. We study the energy levels of such quantum dots and investigate their dependence on a perpendicular magnetic field B and different types of stacking of the graphene layers. The dots are modeled as circular and confined by a truncated parabolic potential which can be realized by nanostructured gates or position-dependent doping. The energy spectra exhibit the intervalley symmetry E-K(e) (m) = -E (h)(K') (m) for the electron (e) and hole (h) states, where m is the angular momentum quantum number and K and K' label the two valleys. The electron and hole spectra for B = 0 are twofold degenerate due to the intervalley symmetry E-K (m) = E-K' [-(m + 1)]. For both ABC [alpha = 1.5 (1.2) for large (small) R] and ABA (alpha = 1) stackings, the lowest-energy levels show approximately a R-alpha dependence on the dot radius R in contrast with the 1/R-3 one for ABC-stacked dots with infinite-mass boundary. As functions of the field B, the oscillator strengths for dipole-allowed transitions differ drastically for the two types of stackings.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000399797200003 Publication Date 2017-04-22
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor Times cited 6 Open Access
  Notes Approved no
  Call Number UA @ admin @ c:irua:152652 Serial 7878
Permanent link to this record
 

 
Author Shayeganfar, F.; Vasu, K.S.; Nair, R.R.; Peeters, F.M.; Neek-Amal, M.
  Title Monolayer alkali and transition-metal monoxides : MgO, CaO, MnO, and NiO Type A1 Journal article
  Year 2017 Publication Physical review B Abbreviated Journal
  Volume 95 Issue 14 Pages 144109
  Keywords (up) A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Two-dimensional crystals with strong interactions between layers has attracted increasing attention in recent years in a variety of fields. In particular, the growth of a single layer of oxide materials (e.g., MgO, CaO, NiO, and MnO) over metallic substrates were found to display different physical properties than their bulk. In this study, we report on the physical properties of a single layer of metallic oxide materials and compare their properties with their bulk and other two-dimensional (2D) crystals. We found that the planar structure of metallic monoxides are unstable whereas the buckled structures are thermodynamically stable. Also, the 2D-MnO and NiO exhibit different magnetic (ferromagnetic) and optical properties than their bulk, whereas band-gap energy and linear stiffness are found to be decreasing from NiO to MgO. Our findings provide insight into oxide thin-film technology applications.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000399792400001 Publication Date 2017-04-20
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor Times cited 21 Open Access
  Notes Approved no
  Call Number UA @ admin @ c:irua:152654 Serial 8278
Permanent link to this record
 

 
Author de Araujo, J.L.B.; Munarin, F.F.; Farias, G.A.; Peeters, F.M.; Ferreira, W.P.
  Title Structure and reentrant percolation in an inverse patchy colloidal system Type A1 Journal article
  Year 2017 Publication Physical Review E Abbreviated Journal
  Volume 95 Issue 6 Pages 062606
  Keywords (up) A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Two-dimensional systems of inverse patchy colloids modeled as disks with a central charge and having their surface decorated with oppositely pointlike charged patches are investigated using molecular dynamics simulations. The self-assembly of the patchy colloids leads to diverse ground state configurations ranging from crystalline arrangements of monomers to linear clusters, ramified linear clusters and to percolated configurations. Two structural phase diagrams are constructed: (1) as a function of the net charge and area fraction, and (2) as a function of the net charge and the range of the pair interaction potential. An interesting reentrant percolation transition is obtained as a function of the net charge of the colloids. We identify distinct mechanisms that lead to the percolation transition.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000404545700005 Publication Date 2017-06-27
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor Times cited 5 Open Access
  Notes Approved no
  Call Number UA @ admin @ c:irua:152628 Serial 8587
Permanent link to this record
 

 
Author da Costa, D.R.; Chaves, A.; Farias, G.A.; Peeters, F.M.
  Title Valley filtering in graphene due to substrate-induced mass potential Type A1 Journal article
  Year 2017 Publication Journal of physics : condensed matter Abbreviated Journal
  Volume 29 Issue 21 Pages 215502
  Keywords (up) A1 Journal article; Condensed Matter Theory (CMT)
  Abstract The interaction of monolayer graphene with specific substrates may break its sublattice symmetry and results in unidirectional chiral states with opposite group velocities in the different Dirac cones (Zarenia et al 2012 Phys. Rev. B 86 085451). Taking advantage of this feature, we propose a valley filter based on a transversal mass kink for low energy electrons in graphene, which is obtained by assuming a defect region in the substrate that provides a change in the sign of the substrate-induced mass and thus creates a non-biased channel, perpendicular to the kink, for electron motion. By solving the time-dependent Schrodinger equation for the tight-binding Hamiltonian, we investigate the time evolution of a Gaussian wave packet propagating through such a system and obtain the transport properties of this graphene-based substrate-induced quantum point contact. Our results demonstrate that efficient valley filtering can be obtained, provided: (i) the electron energy is sufficiently low, i.e. with electrons belonging mostly to the lowest sub-band of the channel, and (ii) the channel length (width) is sufficiently long (narrow). Moreover, even though the transmission probabilities for each valley are significantly affected by impurities and defects in the channel region, the valley polarization in this system is shown to be robust against their presence.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000400092700002 Publication Date 2017-04-24
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0953-8984 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor Times cited 15 Open Access
  Notes Approved no
  Call Number UA @ admin @ c:irua:152636 Serial 8730
Permanent link to this record
 

 
Author Leenaerts, O.; Partoens, B.; Peeters, F.M.; Volodin, A.; van Haesendonck, C.
  Title The work function of few-layer graphene Type A1 Journal article
  Year 2017 Publication Journal of physics : condensed matter Abbreviated Journal
  Volume 29 Issue 3 Pages 035003
  Keywords (up) A1 Journal article; Condensed Matter Theory (CMT)
  Abstract A theoretical and experimental study of the work function of few-layer graphene is reported. The influence of the number of layers on the work function is investigated in the presence of a substrate, a molecular dipole layer, and combinations of the two. The work function of few-layer graphene is almost independent of the number of layers with only a difference between monolayer and multilayer graphene of about 60 meV. In the presence of a charge-donating substrate the charge distribution is found to decay exponentially away from the substrate and this is directly reflected in the work function of few-layer graphene. A dipole layer changes the work function only when placed in between the substrate and few-layer graphene through a change of the charge transfer between the two.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000425250600002 Publication Date 2016-11-16
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0953-8984 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor Times cited 61 Open Access
  Notes Approved no
  Call Number UA @ admin @ c:irua:164938 Serial 8760
Permanent link to this record
 

 
Author Conti, S.; Perali, A.; Hamilton, A.R.; Milošević, M.V.; Peeters, F.M.; Neilson, D.
  Title Chester supersolid of spatially indirect excitons in double-layer semiconductor heterostructures Type A1 Journal article
  Year 2023 Publication Physical review letters Abbreviated Journal
  Volume 130 Issue 5 Pages 057001-57006
  Keywords (up) A1 Journal article; Condensed Matter Theory (CMT)
  Abstract A supersolid, a counterintuitive quantum state in which a rigid lattice of particles flows without resistance, has to date not been unambiguously realized. Here we reveal a supersolid ground state of excitons in a double-layer semiconductor heterostructure over a wide range of layer separations outside the focus of recent experiments. This supersolid conforms to the original Chester supersolid with one exciton per supersolid site, as distinct from the alternative version reported in cold-atom systems of a periodic density modulation or clustering of the superfluid. We provide the phase diagram augmented by the supersolid. This new phase appears at layer separations much smaller than the predicted exciton normal solid, and it persists up to a solid-solid transition where the quantum phase coherence collapses. The ranges of layer separations and exciton densities in our phase diagram are well within reach of the current experimental capabilities.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000968650900001 Publication Date 2023-02-01
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0031-9007; 1079-7114 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 8.6 Times cited 7 Open Access Not_Open_Access
  Notes Approved Most recent IF: 8.6; 2023 IF: 8.462
  Call Number UA @ admin @ c:irua:196742 Serial 8817
Permanent link to this record
 

 
Author Cheng, X.; Xu, W.; Wen, H.; Zhang, J.; Zhang, H.; Li, H.; Peeters, F.M.; Chen, Q.
  Title Electronic properties of 2H-stacking bilayer MoS₂ measured by terahertz time-domain spectroscopy Type A1 Journal article
  Year 2023 Publication Frontiers of physics Abbreviated Journal
  Volume 18 Issue 5 Pages 53303-53311
  Keywords (up) A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Bilayer (BL) molybdenum disulfide (MoS2) is one of the most important electronic structures not only in valleytronics but also in realizing twistronic systems on the basis of the topological mosaics in moire superlattices. In this work, BL MoS2 on sapphire substrate with 2H-stacking structure is fabricated. We apply the terahertz (THz) time-domain spectroscopy (TDS) for examining the basic optoelectronic properties of this kind of BL MoS2. The optical conductivity of BL MoS2 is obtained in temperature regime from 80 K to 280 K. Through fitting the experimental data with the theoretical formula, the key sample parameters of BL MoS2 can be determined, such as the electron density, the electronic relaxation time and the electronic localization factor. The temperature dependence of these parameters is examined and analyzed. We find that, similar to monolayer (ML) MoS2, BL MoS2 with 2H-stacking can respond strongly to THz radiation field and show semiconductor-like optoelectronic features. The theoretical calculations using density functional theory (DFT) can help us to further understand why the THz optoelectronic properties of BL MoS2 differ from those observed for ML MoS2. The results obtained from this study indicate that the THz TDS can be applied suitably to study the optoelectronic properties of BL MoS2 based twistronic systems for novel applications as optical and optoelectronic materials and devices.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000991955300002 Publication Date 2023-05-22
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 2095-0462; 2095-0470 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 7.5 Times cited 3 Open Access OpenAccess
  Notes Approved Most recent IF: 7.5; 2023 IF: 2.579
  Call Number UA @ admin @ c:irua:197398 Serial 8818
Permanent link to this record
 

 
Author Shafiei, M.; Fazileh, F.; Peeters, F.M.; Milošević, M.V.
  Title High Chern number in strained thin films of dilute magnetic topological insulators Type A1 Journal article
  Year 2023 Publication Physical review B Abbreviated Journal
  Volume 107 Issue 19 Pages 195119-6
  Keywords (up) A1 Journal article; Condensed Matter Theory (CMT)
  Abstract The quantum anomalous Hall effect was first observed experimentally by doping the Bi2Se3 materials family with chromium, where 5% doping induces an exchange field of around 0.1 eV. In ultrathin films, a topological phase transition from a normal insulator to a Chern insulator can be induced with an exchange field proportional to the hybridization gap. Subsequent transitions to states with higher Chern numbers require an exchange field larger than the (bulk) band gap, but are prohibited in practice by the detrimental effects of higher doping levels. Here, we show that threshold doping for these phase transitions in thin films is controllable by strain. As a consequence, higher Chern states can be reached with experimentally feasible doping, sufficiently dilute for the topological insulator to remain structurally stable. Such a facilitated realization of higher Chern insulators opens prospects for multichannel quantum computing, higher-capacity circuit interconnects, and energy-efficient electronic devices at elevated temperatures.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000995111000003 Publication Date 2023-05-11
  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
  Impact Factor 3.7 Times cited 2 Open Access OpenAccess
  Notes Approved Most recent IF: 3.7; 2023 IF: 3.836
  Call Number UA @ admin @ c:irua:197295 Serial 8820
Permanent link to this record
 

 
Author Pandey, T.; Peeters, F.M.; Milošević, M.V.
  Title High thermoelectric figure of merit in p-type Mg₃Si₂Te₆: role of multi-valley bands and high anharmonicity Type A1 Journal article
  Year 2023 Publication Journal of materials chemistry C : materials for optical and electronic devices Abbreviated Journal
  Volume 11 Issue 33 Pages 11185-11194
  Keywords (up) A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Silicon-based materials are attractive for thermoelectric applications due to their thermal stability, chemical inertness, and natural abundance of silicon. Here, using a combination of first-principles and Boltzmann transport calculations we report the thermoelectric properties of the recently synthesized compound Mg3Si2Te6. Our analysis reveals that Mg3Si2Te6 is a direct bandgap semiconductor with a bandgap of 1.6 eV. The combination of heavy and light valence bands, along with a high valley degeneracy, results in a large power factor under p-type doping. We also find that Mg is weakly bonded both within and between the layers, leading to low phonon group velocities. The vibrations of the Mg atoms are localized and make a significant contribution to phonon-phonon scattering. This high anharmonicity, coupled with low phonon group velocity, results in a low lattice thermal conductivity of & kappa;(l) = 0.5 W m(-1) K-1 at room temperature, along the cross-plane direction. Combining excellent electronic transport properties and low & kappa;(l), p-type Mg3Si2Te6 achieves figure-of-merit (zT) values greater than 1 at temperatures above 600 K. Specifically, a zT of 2.0 is found at 900 K along the cross-plane direction. Our findings highlight the importance of structural complexity and chemical bonding in electronic and phonon transport, providing guiding insights for further design of Si-based thermoelectrics.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 001041124900001 Publication Date 2023-07-26
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 2050-7526; 2050-7534 ISBN Additional Links UA library record; WoS full record
  Impact Factor 6.4 Times cited 1 Open Access Not_Open_Access
  Notes Approved Most recent IF: 6.4; 2023 IF: 5.256
  Call Number UA @ admin @ c:irua:198296 Serial 8821
Permanent link to this record
 

 
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 7 Pages 075401-75408
  Keywords (up) 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
Permanent link to this record
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