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Author Ozcan, M.; Ozen, S.; Yagmurcukardes, M.; Sahin, H. pdf  doi
openurl 
  Title Structural, electronic and vibrational properties of ultra-thin octahedrally coordinated structure of EuO2 Type (up) A1 Journal article
  Year 2020 Publication Journal Of Magnetism And Magnetic Materials Abbreviated Journal J Magn Magn Mater  
  Volume 493 Issue 493 Pages 165668  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract Novel stable ultra-thin phases of europium oxide are investigated by means of state-of-the-art first principles calculations. Total energy calculations show that single layers of EuO2 and Eu(OH)(2) can be stabilized in an octahedrally coordinated (1T) atomic structure. However, phonon calculations reveal that although both structures are energetically feasible, only the 1T-EuO2 phase has dynamical stability. The phonon spectrum of 1T-EuO2 displays three Raman active modes; a non-degenerate out-of-plane A(1g) mode at 353.5 cm(-1) and two doubly-degenerate in-plane E-g modes at 304.3 cm(-1). Furthermore, magnetic ground state and electronic band dispersion calculations show that the single layer EuO2 is a metal with net magnetic moment of 5(mu B) per unitcell resulting in a half-metallic ferrimagnetic behavior. Moreover, robustness of the half-metallic ferrimagnetic characteristics of EuO2 is confirmed by the application of electric field and charging. Single layer 1T-EuO2, with its stable ultra-thin structure and half-metallic ferrimagnetic feature, is a promising novel material for nanoscale electronic and spintronic applications.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000486397800003 Publication Date 2019-08-03  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0304-8853 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.7 Times cited 1 Open Access  
  Notes ; Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure). HS acknowledges financial support from the TUBITAK under the project number 117F095. MY is supported by the Flemish Science Foundation (FWO-Vl) by a postdoctoral fellowship. ; Approved Most recent IF: 2.7; 2020 IF: 2.63  
  Call Number UA @ admin @ c:irua:162755 Serial 6323  
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Author Eren, I.; Ozen, S.; Sozen, Y.; Yagmurcukardes, M.; Sahin, H. url  doi
openurl 
  Title Vertical van der Waals heterostructure of single layer InSe and SiGe Type (up) A1 Journal article
  Year 2019 Publication The journal of physical chemistry: C : nanomaterials and interfaces Abbreviated Journal J Phys Chem C  
  Volume 123 Issue 51 Pages 31232-31237  
  Keywords A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)  
  Abstract We present a first-principles investigation on the stability, electronic structure, and mechanical response of ultrathin heterostructures composed of single layers of InSe and SiGe. First, by performing total energy optimization and phonon calculations, we show that single layers of InSe and SiGe can form dynamically stable heterostructures in 12 different stacking types. Valence and conduction band edges of the heterobilayers form a type-I heterojunction having a tiny band gap ranging between 0.09 and 0.48 eV. Calculations on elastic-stiffness tensor reveal that two mechanically soft single layers form a heterostructure which is stiffer than the constituent layers because of relatively strong interlayer interaction. Moreover, phonon analysis shows that the bilayer heterostructure has highly Raman active modes at 205.3 and 43.7 cm(-1), stemming from the out-of-plane interlayer mode and layer breathing mode, respectively. Our results show that, as a stable type-I heterojunction, ultrathin heterobilayer of InSe/SiGe holds promise for nanoscale device applications.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000505632900050 Publication Date 2019-12-03  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1932-7447; 1932-7455 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 4.536 Times cited Open Access  
  Notes Approved Most recent IF: 4.536  
  Call Number UA @ admin @ c:irua:165718 Serial 6332  
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Author Kahraman, Z.; Yagmurcukardes, M.; Sahin, H. pdf  doi
openurl 
  Title Functionalization of single-layer TaS₂ and formation of ultrathin Janus structures Type (up) A1 Journal article
  Year 2020 Publication Journal Of Materials Research Abbreviated Journal J Mater Res  
  Volume 35 Issue 11 Pages 1397-1406  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract Ab initio calculations are performed to investigate the structural, vibrational, electronic, and piezoelectric properties of functionalized single layers of TaS2. We find that single-layer TaS2 is a suitable host material for functionalization via fluorination and hydrogenation. The one-side fluorinated (FTaS2) and hydrogenated (HTaS2) single layers display indirect gap semiconducting behavior in contrast to bare metallic TaS2. On the other hand, it is shown that as both surfaces of TaS2 are saturated anti-symmetrically, the formed Janus structure is a dynamically stable metallic single layer. In addition, it is revealed that out-of-plane piezoelectricity is created in all anti-symmetric structures. Furthermore, the Janus-type single-layer has the highest specific heat capacity to which longitudinal and transverse acoustical phonon modes have contribution at low temperatures. Our findings indicate that single-layer TaS2 is suitable for functionalization via H and F atoms that the formed, anti-symmetric structures display distinctive electronic, vibrational, and piezoelectric properties.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000540764300005 Publication Date 2020-04-08  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0884-2914 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.7 Times cited 1 Open Access  
  Notes ; Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure). H.S. Acknowledges financial support from the TUBITAK under the project number 117F095. H.S. acknowledges support from Turkish Academy of Sciences under the GEBIP program. This work is supported by the Flemish Science Foundation (FWO-Vl) by a post-doctoral fellowship (M.Y.). ; Approved Most recent IF: 2.7; 2020 IF: 1.673  
  Call Number UA @ admin @ c:irua:170185 Serial 6525  
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Author Sozen, Y.; Eren, I.; Ozen, S.; Yagmurcukardes, M.; Sahin, H. pdf  url
doi  openurl
  Title Interaction of Ge with single layer GaAs : from Ge-island nucleation to formation of novel stable monolayers Type (up) A1 Journal article
  Year 2020 Publication Applied Surface Science Abbreviated Journal Appl Surf Sci  
  Volume 505 Issue Pages 144218-7  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract In this study, reactivity of single-layer GaAs against Ge atoms is studied by means of ab initio density functional theory calculations. Firstly, it is shown that Ge atoms interact quite strongly with the GaAs layer which allows the formation of Ge islands while it hinders the growth of detached germanene monolayers. It is also predicted that adsorption of Ge atoms on GaAs single-layer lead to formation of two novel stable single-layer crystal structures, namely 1H-GaGeAs and 1H(A)-GaGeAs. Both the total energy optimizations and the calculated vibrational spectra indicate the dynamical stability of both single layer structures. Moreover, although both structures crystallize in 1H phase, 1H-GaGeAs and 1H(A)-GaGeAs exhibit distinctive vibrational features in their Raman spectra which is quite important for distinguishing the structures. In contrast to the semiconducting nature of single-layer GaAs, both polytypes of GaGeAs exhibit metallic behavior confirmed by the electronic band dispersions. Furthermore, the linear-elastic constants, in-plane stiffness and Poisson ratio, reveal the ultrasoft nature of the GaAs and GaGeAs structures and the rigidity of GaAs is found to be slightly enhanced via Ge adsorption. With their stable, ultra-thin and metallic properties, predicted single-layer GaGeAs structures can be promising candidates for nanoscale electronic and mechanical applications.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000510846500026 Publication Date 2019-11-02  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0169-4332 ISBN Additional Links UA library record; WoS full record  
  Impact Factor 6.7 Times cited Open Access  
  Notes ; Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid eInfrastructure). H.S. acknowledges financial support from the Scientific and Technological Research Council of Turkey (TUBITAK) under the project number 117F095. H.S. acknowledges support from Turkish Academy of Sciences under the GEBIP program. This work is supported by the Flemish Science Foundation (FWO-Vl) by a postdoctoral fellowship (M.Y.). ; Approved Most recent IF: 6.7; 2020 IF: 3.387  
  Call Number UA @ admin @ c:irua:167733 Serial 6548  
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Author Plumadore, R.; Baskurt, M.; Boddison-Chouinard, J.; Lopinski, G.; Modarresi, M.; Potasz, P.; Hawrylak, P.; Sahin, H.; Peeters, F.M.; Luican-Mayer, A. url  doi
openurl 
  Title Prevalence of oxygen defects in an in-plane anisotropic transition metal dichalcogenide Type (up) A1 Journal article
  Year 2020 Publication Physical Review B Abbreviated Journal Phys Rev B  
  Volume 102 Issue 20 Pages 205408  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract Atomic scale defects in semiconductors enable their technological applications and realization of different quantum states. Using scanning tunneling microscopy and spectroscopy complemented by ab initio calculations we determine the nature of defects in the anisotropic van der Waals layered semiconductor ReS2. We demonstrate the in-plane anisotropy of the lattice by directly visualizing chains of rhenium atoms forming diamond-shaped clusters. Using scanning tunneling spectroscopy we measure the semiconducting gap in the density of states. We reveal the presence of lattice defects and by comparison of their topographic and spectroscopic signatures with ab initio calculations we determine their origin as oxygen atoms absorbed at lattice point defect sites. These results provide an atomic-scale view into the semiconducting transition metal dichalcogenides, paving the way toward understanding and engineering their properties.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000587595800007 Publication Date 2020-11-09  
  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 3.7 Times cited 6 Open Access  
  Notes ; The authors acknowledge funding from National Sciences and Engineering Research Council (NSERC) Discovery Grant No. RGPIN-2016-06717. We also acknowledge the support of the Natural Sciences and Engineering Research Council of Canada (NSERC) through QC2DM Strategic Project No. STPGP 521420. P.H. thanks uOttawa Research Chair in Quantum Theory of Materials for support. P.P. acknowledges partial financial support from National Science Center (NCN), Poland, Grant Maestro No. 2014/14/A/ST3/00654, and calculations were performed in theWroclaw Center for Networking and Supercomputing. H.S. acknowledges financial support from TUBITAK under Project No. 117F095 and from Turkish Academy of Sciences under the GEBIP program. Our computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid eInfrastructure). ; Approved Most recent IF: 3.7; 2020 IF: 3.836  
  Call Number UA @ admin @ c:irua:173525 Serial 6584  
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Author Yagmurcukardes, M.; Qin, Y.; Ozen, S.; Sayyad, M.; Peeters, F.M.; Tongay, S.; Sahin, H. pdf  doi
openurl 
  Title Quantum properties and applications of 2D Janus crystals and their superlattices Type (up) A1 Journal article
  Year 2020 Publication Applied Physics Reviews Abbreviated Journal Appl Phys Rev  
  Volume 7 Issue 1 Pages 011311-11316  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract Two-dimensional (2D) Janus materials are a new class of materials with unique physical, chemical, and quantum properties. The name “Janus” originates from the ancient Roman god which has two faces, one looking to the future while the other facing the past. Janus has been used to describe special types of materials which have two faces at the nanoscale. This unique atomic arrangement has been shown to present rather exotic properties with applications in biology, chemistry, energy conversion, and quantum sciences. This review article aims to offer a comprehensive review of the emergent quantum properties of Janus materials. The review starts by introducing 0D Janus nanoparticles and 1D Janus nanotubes, and highlights their difference from classical ones. The design principles, synthesis, and the properties of graphene-based and chalcogenide-based Janus layers are then discussed. A particular emphasis is given to colossal built-in potential in 2D Janus layers and resulting quantum phenomena such as Rashba splitting, skyrmionics, excitonics, and 2D magnetic ordering. More recent theoretical predictions are discussed in 2D Janus superlattices when Janus layers are stacked onto each other. Finally, we discuss the tunable quantum properties and newly predicted 2D Janus layers waiting to be experimentally realized. The review serves as a complete summary of the 2D Janus library and predicted quantum properties in 2D Janus layers and their superlattices.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000519611500001 Publication Date 2020-02-21  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1931-9401 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 15 Times cited 107 Open Access  
  Notes ; S.T. acknowledges support from NSF Contract Nos. DMR 1552220, DMR 1904716, and NSF CMMI 1933214. H.S. acknowledges financial support from the Scientific and Technological Research Council of Turkey (TUBITAK) under Project No. 117F095. H.S. acknowledges support from the Turkish Academy of Sciences under the GEBIP program. M.Y. is supported by the Flemish Science Foundation (FWO-Vl) through a postdoctoral fellowship. Part of this work was supported by the FLAG-ERA project TRANS2D-TMD. ; Approved Most recent IF: 15; 2020 IF: 13.667  
  Call Number UA @ admin @ c:irua:167712 Serial 6591  
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Author Baskurt, M.; Yagmurcukardes, M.; Peeters, F.M.; Sahin, H. pdf  doi
openurl 
  Title Stable single-layers of calcium halides (CaX₂, X = F, Cl, Br, I) Type (up) A1 Journal article
  Year 2020 Publication Journal Of Chemical Physics Abbreviated Journal J Chem Phys  
  Volume 152 Issue 16 Pages 164116-164118  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract By means of density functional theory based first-principles calculations, the structural, vibrational, and electronic properties of 1H- and 1T-phases of single-layer CaX2 (X = F, Cl, Br, or I) structures are investigated. Our results reveal that both the 1H- and 1T-phases are dynamically stable in terms of their phonon band dispersions with the latter being the energetically favorable phase for all single-layers. In both phases of single-layer CaX2 structures, significant phonon softening occurs as the atomic radius increases. In addition, each structural phase exhibits distinctive Raman active modes that enable one to characterize either the phase or the structure via Raman spectroscopy. The electronic band dispersions of single-layer CaX2 structures reveal that all structures are indirect bandgap insulators with a decrease in bandgaps from fluorite to iodide crystals. Furthermore, the calculated linear elastic constants, in-plane stiffness, and Poisson ratio indicate the ultra-soft nature of CaX2 single-layers, which is quite important for their nanoelastic applications. Overall, our study reveals that with their dynamically stable 1T- and 1H-phases, single-layers of CaX2 crystals can be alternative ultra-thin insulators.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000531819100001 Publication Date 2020-04-29  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0021-9606 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 4.4 Times cited 10 Open Access  
  Notes ; Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure). H.S. acknowledges financial support from the TUBITAK under Project No. 117F095. H.S. acknowledges support from the Turkish Academy of Sciences under the GEBIP program. M.Y. was supported by a postdoctoral fellowship from the Flemish Science Foundation (FWO-Vl). ; Approved Most recent IF: 4.4; 2020 IF: 2.965  
  Call Number UA @ admin @ c:irua:169543 Serial 6615  
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Author Baskurt, M.; Eren, I.; Yagmurcukardes, M.; Sahin, H. pdf  doi
openurl 
  Title Vanadium dopant- and strain-dependent magnetic properties of single-layer VI₃ Type (up) A1 Journal article
  Year 2020 Publication Applied Surface Science Abbreviated Journal Appl Surf Sci  
  Volume 508 Issue Pages 144937-6  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract Motivated by the recent synthesis of two-dimensional VI3 [Kong et al. Adv. Mater. 31, 1808074 (2019)], we investigate the effect of V doping on the magnetic and electronic properties of monolayer VI3 by means of first-principles calculations. The dynamically stable semiconducting ferromagnetic (FM) and antiferromagnetic (AFM) phases of monolayer VI3 are found to display distinctive vibrational features that the magnetic state can be distinguished by Raman spectroscopy. In order to clarify the effect of experimentally observed excessive V atoms, the magnetic and electronic properties of the V-doped VI3 structures are analyzed. Our findings indicate that partially doped VI3 structures display FM ground state while the fully-doped structure exhibits AFM ground state. The fully-doped monolayer VI3 is found to be a semiconductor with a relatively larger band gap than its pristine structure. In addition, strain-dependent electronic and magnetic properties of fully- and partially-doped VI3 structures reveal that pristine monolayer displays a FM-to-AFM phase transition with robust semiconducting nature for 5% of compressive strain, while fully-doped monolayer VI3 structure possesses AFM-to-FM semiconducting transition at tensile strains larger than 4%. In contrast, the partially-doped VI3 monolayers are found to display robust FM ground state under biaxial strain. Its dopant and strain tunable electronic and magnetic nature makes monolayer VI3 a promising material for applications in nanoscale spintronic devices.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000516818700040 Publication Date 2019-12-24  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0169-4332 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 6.7 Times cited 10 Open Access  
  Notes ; Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure). H.S. Acknowledges financial support from the TUBITAK under the project number 117F095. H.S. acknowledges support from Turkish Academy of Sciences under the GEBIP program. This work is supported by the Flemish Science Foundation (FWO-Vl) by a postdoctoral fellowship (M.Y.). ; Approved Most recent IF: 6.7; 2020 IF: 3.387  
  Call Number UA @ admin @ c:irua:168595 Serial 6652  
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Author Ceyhan, E.; Yagmurcukardes, M.; Peeters, F.M.; Sahin, H. doi  openurl
  Title Electronic and magnetic properties of single-layer FeCl₂ with defects Type (up) A1 Journal article
  Year 2021 Publication Physical Review B Abbreviated Journal Phys Rev B  
  Volume 103 Issue 1 Pages 014106  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract The formation of lattice defects and their effect on the electronic properties of single-layer FeCl2 are investigated by means of first-principles calculations. Among the vacancy defects, namely mono-, di-, and three-Cl vacancies and mono-Fe vacancy, the formation of mono-Cl vacancy is the most preferable. Comparison of two different antisite defects reveals that the formation of the Fe-antisite defect is energetically preferable to the Cl-antisite defect. While a single Cl vacancy leads to a 1 mu(B) decrease in the total magnetic moment of the host lattice, each Fe vacant site reduces the magnetic moment by 4 mu(B). However, adsorption of an excess Cl atom on the surface changes the electronic structure to a ferromagnetic metal or to a ferromagnetic semiconductor depending on the adsorption site without changing the ferromagnetic state of the host lattice. Both Cl-antisite and Fe-antisite defected domains change the magnetic moment of the host lattice by -1 mu(B) and +3 mu(B), respectively. The electronic ground state of defected structures reveals that (i) single-layer FeCl2 exhibits half-metallicity under the formation of vacancy and Cl-antisite defects; (ii) ferromagnetic metallicity is obtained when a single Cl atom is adsorbed on upper-Cl and Fe sites, respectively; and (iii) ferromagnetic semiconducting behavior is found when a Cl atom is adsorbed on a lower-Cl site or a Fe-antisite defect is formed. Simulated scanning electron microscope images show that atomic-scale identification of defect types is possible from their electronic charge density. Further investigation of the periodically Fe-defected structures reveals that the formation of the single-layer FeCl3 phase, which is a dynamically stable antiferromagnetic semiconductor, is possible. Our comprehensive analysis on defects in single-layer FeCl2 will complement forthcoming experimental observations.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000606969400002 Publication Date 2021-01-13  
  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 5 Open Access Not_Open_Access  
  Notes ; Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure), and by Flemish Supercomputer Center (VSC). H.S. acknowledges financial support from the Scientific and Technological Research Council of Turkey (TUBITAK) under Project No. 117F095. M.Y. was supported by the Flemish Science Foundation (FWO-Vl) by a postdoctoral fellowship. ; Approved Most recent IF: 3.836  
  Call Number UA @ admin @ c:irua:176039 Serial 6689  
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Author Kahraman, Z.; Baskurt, M.; Yagmurcukardes, M.; Chaves, A.; Sahin, H. pdf  doi
openurl 
  Title Stable Janus TaSe₂ single-layers via surface functionalization Type (up) A1 Journal article
  Year 2021 Publication Applied Surface Science Abbreviated Journal Appl Surf Sci  
  Volume 538 Issue Pages 148064  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract First-principles calculations are performed in order to investigate the formation of Janus structures of single layer TaSe2. The structural optimizations and phonon band dispersions reveal that the formation and stability of hydrogenated (HTaSe2), fluorinated (FTaSe2), and the one-side hydrogenated and one-side fluorinated (Janus-HTaSe2F) single-layers are feasible in terms of their phonon band dispersions. It is shown that bare metallic single-layer TaSe2 can be turned into a semiconductor as only one of its surface is functionalized while it remains as a metal via its two surfaces functionalization. In addition, the semiconducting nature of single-layers HTaSe2 and FTaSe2 and the metallic behavior of Janus TaSe2 are found to be robust under applied uniaxal strains. Further analysis on piezoelectric properties of the predicted single-layers reveal the enhanced in-plane and out of-plane piezoelectricity via formed Janus-HTaSe2F. Our study indicates that single-layer TaSe2 is a suitable host material for surface functionalization via fluorination and hydrogenation which exhibit distinctive electronic and vibrational properties.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000595860900001 Publication Date 2020-10-16  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0169-4332 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.387 Times cited Open Access Not_Open_Access  
  Notes ; Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid eInfrastructure). HS acknowledges support from Turkiye Bilimler Akademisi -Turkish Academy of Sciences under the GEBIP program. This work was supported by the Flemish Science Foundation (FWO-Vl) by a postdoctoral fellowship (M.Y.). ; Approved Most recent IF: 3.387  
  Call Number UA @ admin @ c:irua:174964 Serial 6699  
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Author Yayak, Y.O.; Sozen, Y.; Tan, F.; Gungen, D.; Gao, Q.; Kang, J.; Yagmurcukardes, M.; Sahin, H. pdf  doi
openurl 
  Title First-principles investigation of structural, Raman and electronic characteristics of single layer Ge3N4 Type (up) A1 Journal article
  Year 2022 Publication Applied surface science Abbreviated Journal Appl Surf Sci  
  Volume 572 Issue Pages 151361  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract By means of density functional theory-based first-principle calculations, the structural, vibrational and electronic properties of single-layer Ge3N4 are investigated. Structural optimizations and phonon band dispersions reveal that single-layer ultrathin form of Ge3N4 possesses a dynamically stable buckled structure with large hexagonal holes. Predicted Raman spectrum of single-layer Ge3N4 indicates that the buckled holey structure of the material exhibits distinctive vibrational features. Electronic band dispersion calculations indicate the indirect band gap semiconducting nature of single-layer Ge3N4. It is also proposed that single-layer Ge3N4 forms type-II vertical heterostructures with various planar and puckered 2D materials except for single-layer GeSe which gives rise to a type-I band alignment. Moreover, the electronic properties of single-layer Ge3N4 are investigated under applied external in-plane strain. It is shown that while the indirect gap behavior of Ge3N4 is unchanged by the applied strain, the energy band gap increases (decreases) with tensile (compressive) strain.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000723664000006 Publication Date 2021-10-01  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0169-4332 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 6.7 Times cited Open Access Not_Open_Access  
  Notes Approved Most recent IF: 6.7  
  Call Number UA @ admin @ c:irua:184752 Serial 6993  
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Author Yagmurcukardes, M.; Sozen, Y.; Baskurt, M.; Peeters, F.M.; Sahin, H. doi  openurl
  Title Interface-dependent phononic and optical properties of GeO/MoSO heterostructures Type (up) A1 Journal article
  Year 2021 Publication Nanoscale Abbreviated Journal Nanoscale  
  Volume Issue Pages  
  Keywords A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)  
  Abstract The interface-dependent electronic, vibrational, piezoelectric, and optical properties of van der Waals heterobilayers, formed by buckled GeO (b-GeO) and Janus MoSO structures, are investigated by means of first-principles calculations. The electronic band dispersions show that O/Ge and S/O interface formations result in a type-II band alignment with direct and indirect band gaps, respectively. In contrast, O/O and S/Ge interfaces give rise to the formation of a type-I band alignment with an indirect band gap. By considering the Bethe-Salpeter equation (BSE) on top of G(0)W(0) approximation, it is shown that different interfaces can be distinguished from each other by means of the optical absorption spectra as a consequence of the band alignments. Additionally, the low- and high-frequency regimes of the Raman spectra are also different for each interface type. The alignment of the individual dipoles, which is interface-dependent, either weakens or strengthens the net dipole of the heterobilayers and results in tunable piezoelectric coefficients. The results indicate that the possible heterobilayers of b-GeO/MoSO asymmetric structures possess various electronic, optical, and piezoelectric properties arising from the different interface formations and can be distinguished by means of various spectroscopic techniques.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000738899600001 Publication Date 2021-12-09  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2040-3364 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 7.367 Times cited 2 Open Access Not_Open_Access  
  Notes Approved Most recent IF: 7.367  
  Call Number UA @ admin @ c:irua:184722 Serial 6998  
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Author Baskurt, M.; Nair, R.R.; Peeters, F.M.; Sahin, H. pdf  doi
openurl 
  Title Ultra-thin structures of manganese fluorides : conversion from manganese dichalcogenides by fluorination Type (up) A1 Journal article
  Year 2021 Publication Physical Chemistry Chemical Physics Abbreviated Journal Phys Chem Chem Phys  
  Volume 23 Issue 17 Pages 10218-10224  
  Keywords 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  
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Author Sozen, Y.; Yagmurcukardes, M.; Sahin, H. doi  openurl
  Title Vibrational and optical identification of GeO₂ and GeO single layers : a first-principles study Type (up) A1 Journal article
  Year 2021 Publication Physical Chemistry Chemical Physics Abbreviated Journal Phys Chem Chem Phys  
  Volume 23 Issue 37 Pages 21307-21315  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract In the present work, the identification of two hexagonal phases of germanium oxides (namely GeO2 and GeO) through the vibrational and optical properties is reported using density functional theory calculations. While structural optimizations show that single-layer GeO2 and GeO crystallize in 1T and buckled phases, phonon band dispersions reveal the dynamical stability of each structure. First-order off-resonant Raman spectral predictions demonstrate that each free-standing single-layer possesses characteristic peaks that are representative for the identification of the germanium oxide phase. On the other hand, electronic band dispersion analysis shows the insulating and large-gap semiconducting nature of single-layer GeO2 and GeO, respectively. Moreover, optical absorption, reflectance, and transmittance spectra obtained by means of G(0)W(0)-BSE calculations reveal the existence of tightly bound excitons in each phase, displaying strong optical absorption. Furthermore, the excitonic gaps are found to be at deep UV and visible portions of the spectrum, for GeO2 and GeO crystals, with energies of 6.24 and 3.10 eV, respectively. In addition, at the prominent excitonic resonances, single-layers display high reflectivity with a zero transmittance, which is another indication of the strong light-matter interaction inside the crystal medium.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000697364300001 Publication Date 2021-09-02  
  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 Open Access Not_Open_Access  
  Notes Approved Most recent IF: 4.123  
  Call Number UA @ admin @ c:irua:181571 Serial 7044  
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Author Duran, T.A.; Šabani, D.; Milošević, M.V.; Sahin, H. doi  openurl
  Title Experimental and theoretical investigation of synthesis and properties of dodecanethiol-functionalized MoS₂ Type (up) A1 Journal article
  Year 2023 Publication Physical chemistry, chemical physics Abbreviated Journal  
  Volume 25 Issue 40 Pages 27141-27150  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract Herein, we investigate the DDT (1-dodecanethiol) functionalization of exfoliated MoS2 by using experimental and theoretical tools. For the functionalization of MoS2, DDT treatment was incorporated into the conventional NMP (N-methyl pyrrolidone) exfoliation procedure. Afterward, it has been demonstrated that the functionalization process is successful through optical, morphological and theoretical analysis. The D, G and 2LA peaks seen in the Raman spectrum of exfoliated NMP-MoS2 particles, indicate the formation of graphitic species on MoS2 sheets. In addition, as the DDT ratio increases, the vacant sites on MoS2 sheets diminish. Moreover, at an optimized ratio of DDT-NMP, the maximum number of graphitic quantum dots (GQDs) is observed on MoS2 nanosheets. Specifically, the STEM and AFM data confirm that GQDs reside on the MoS2 nano-sheets and also that the particle size of the DDT-MoS2 is mostly fixed, while the NMP-MoS2 show many smaller and distributed sizes. The comparison of PL intensities of the NMP-MoS2 and DDT-MoS2 samples states a 10-fold increment is visible, and a 60-fold increment in NIR region photoluminescent properties. Moreover, our results lay out understanding and perceptions on the surface and edge chemistry of exfoliated MoS2 and open up more opportunities for MoS2 and GQD particles with broader applications.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 001076998800001 Publication Date 2023-09-29  
  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 Times cited Open Access  
  Notes Approved no  
  Call Number UA @ admin @ c:irua:200284 Serial 9033  
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