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	Author	Iyikanat, F.; Sahin, H.; Senger, R.T.; Peeters, F.M.
	Title	Vacancy formation and oxidation characteristics of single layer TiS₃			Type	A1 Journal article
	Year	2015	Publication	The journal of physical chemistry: C : nanomaterials and interfaces	Abbreviated Journal	J Phys Chem C
	Volume	119	Issue	119	Pages	10709-10715
	Keywords	A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
	Abstract	The structural, electronic, and magnetic properties of pristine, defective, and oxidized monolayer TiS3 are investigated using first-principles calculations in the framework of density functional theory. We found that a single layer of TiS3 is a direct band gap semiconductor, and the bonding nature of the crystal is fundamentally different from other transition metal chalcogenides. The negatively charged surfaces of single layer TiS3 makes this crystal a promising material for lubrication applications. The formation energies of possible vacancies, i.e. S, Ti, TiS, and double S, are investigated via total energy optimization calculations. We found that the formation of a single S vacancy was the most likely one among the considered vacancy types. While a single S vacancy results in a nonmagnetic, semiconducting character with an enhanced band gap, other vacancy types induce metallic behavior with spin polarization of 0.3-0.8 mu(B). The reactivity of pristine and defective TiS3 crystals against oxidation was investigated using conjugate gradient calculations where we considered the interaction with atomic O, O-2, and O-3. While O-2 has the lowest binding energy with 0.05-0.07 eV, O-3 forms strong bonds stable even at moderate temperatures. The strong interaction (3.9-4.0 eV) between atomic O and TiS3 results in dissociative adsorption of some O-containing molecules. In addition, the presence of S-vacancies enhances the reactivity of the surface with atomic O, whereas it had a negative effect on the reactivity with O-2 and O-3 molecules.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000354912200063	Publication Date	2015-04-28
	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	51	Open Access
	Notes	; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Methusalem foundation of the Flemish government. Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure), and HPC infrastructure of the University of Antwerp (CalcUA), a division of the Flemish Supercomputer Center (VSC), which is funded by the Hercules foundation. H.S. is supported by a FWO Pegasus Marie Curie Fellowship. RI., H.S., and R.T.S. acknowledge the support from TUBITAK through project 114F397. ;			Approved	Most recent IF: 4.536; 2015 IF: 4.772
	Call Number	c:irua:126410			Serial	3829
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	Author	Torun, E.; Sahin, H.; Cahangirov, S.; Rubio, A.; Peeters, F.M.
	Title	Anisotropic electronic, mechanical, and optical properties of monolayer WTe2			Type	A1 Journal article
	Year	2016	Publication	Journal of applied physics	Abbreviated Journal	J Appl Phys
	Volume	119	Issue	7	Pages	074307
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	Using first-principles calculations, we investigate the electronic, mechanical, and optical properties of monolayer WTe2. Atomic structure and ground state properties of monolayer WTe2 (T-d phase) are anisotropic which are in contrast to similar monolayer crystals of transition metal dichalcogenides, such as MoS2, WS2, MoSe2, WSe2, and MoTe2, which crystallize in the H-phase. We find that the Poisson ratio and the in-plane stiffness is direction dependent due to the symmetry breaking induced by the dimerization of the W atoms along one of the lattice directions of the compound. Since the semimetallic behavior of the T-d phase originates from this W-W interaction (along the a crystallographic direction), tensile strain along the dimer direction leads to a semimetal to semiconductor transition after 1% strain. By solving the Bethe-Salpeter equation on top of single shot G(0)W(0) calculations, we predict that the absorption spectrum of T-d-WTe2 monolayer is strongly direction dependent and tunable by tensile strain. (C) 2016 AIP Publishing LLC.
	Address
	Corporate Author				Thesis
	Publisher	American Institute of Physics	Place of Publication	New York, N.Y.	Editor
	Language		Wos	000375158000022	Publication Date	2016-02-19
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0021-8979; 1089-7550	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	2.068	Times cited	62	Open Access
	Notes	; This work was supported by the Flemish Science Foundation (FWO-V1) and the Methusalem foundation of the Flemish government. Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure). H.S. was supported by a FWO Pegasus Long Marie Curie Fellowship. S.C. and A.R. acknowledge the financial support from the Marie Curie grant FP7-PEOPLE-2013-IEF Project No. 628876, European Research Council (ERC-2010-AdG-267374), Spanish grant (FIS2013-46159-C3-1-P), Grupos Consolidados (IT578-13), and AFOSR Grant No. FA2386-15-1-0006 AOARD 144088, H2020-NMP-2014 project MOSTOPHOS, GA No. SEP-210187476, and COST Action MP1306 (EUSpec). S.C. acknowledges the support from The Scientific and Technological Research Council of Turkey (TUBITAK) under Project No. 115F388. ;			Approved	Most recent IF: 2.068
	Call Number	UA @ lucian @ c:irua:144747			Serial	4640
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	Author	Badalov, S.V.; Yagmurcukardes, M.; Peeters, F.M.; Sahin, H.
	Title	Enhanced stability of single-layer w-Gallenene through hydrogenation			Type	A1 Journal article
	Year	2018	Publication	The journal of physical chemistry: C : nanomaterials and interfaces	Abbreviated Journal	J Phys Chem C
	Volume	122	Issue	49	Pages	28302-28309
	Keywords	A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
	Abstract	Using density functional theory based first-principles calculations, the effect of surface hydrogenation on the structural, dynamical, electronic, and mechanical properties of monolayer washboard-gallenene (w-gallenene) is investigated. It is found that the dynamically stabilized strained monolayer of w-gallenene has a metallic nonmagnetic ground state. Both one-sided and two-sided hydrogenations of w-gallenene suppress its dynamical instability even when unstrained. Unlike one-sided hydrogenated monolayer w-gallenene (os-w-gallenene), two-sided hydrogenated monolayer w-gallenene (ts-w-gallenene) possesses the same crystal structure as w-gallenene. Electronic band structure calculations reveal that monolayers of hydrogenated derivatives of w-gallenene exhibit also metallic nonmagnetic ground state. Moreover, the linear-elastic constants, in-plane stiffness and Poisson ratio, are enhanced by hydrogenation, which is opposite to the behavior of other hydrogenated monolayer crystals. Furthermore, monolayer w-gallenene and ts-w-gallenene remain dynamically stable up to relatively higher biaxial strains as compared to borophene. With its enhanced dynamical stability, robust metallic character, and enhanced linear-elastic properties, hydrogenated monolayer w-gallenene is a potential candidate for nanodevice applications as a two-dimensional flexible metal.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000453488300053	Publication Date	2018-11-12
	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	20	Open Access
	Notes	; Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure). H.S. acknowledges support from Turkish Academy of Sciences under the GEBIP program. This work was supported by FLAG-ERA project TRANS-2D-TMD. This work is supported by the Flemish Science Foundation (FWO-Vl) by a postdoctoral fellowship (M.Y.). ;			Approved	Most recent IF: 4.536
	Call Number	UA @ admin @ c:irua:156229			Serial	5210
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	Author	Kahraman, Z.; Kandemir, A.; Yagmurcukardes, M.; Sahin, H.
	Title	Single-layer Janus-type platinum dichalcogenides and their heterostructures			Type	A1 Journal article
	Year	2019	Publication	The journal of physical chemistry: C : nanomaterials and interfaces	Abbreviated Journal	J Phys Chem C
	Volume	123	Issue	7	Pages	4549-4557
	Keywords	A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
	Abstract	Ultrathin two-dimensional Janus-type platinum dichalcogenide crystals formed by two different atoms at opposite surfaces are investigated by performing state-of-the-art density functional theory calculations. First, it is shown that single-layer PtX2 structures (where X = S, Se, or Te) crystallize into the dynamically stable IT phase and are indirect band gap semiconductors. It is also found that the substitutional chalcogen doping in all PtX2 structures is favorable via replacement of surface atoms with a smaller chalcogen atom, and such a process leads to the formation of Janus-type platinum dichalcogenides (XPtY, where X and Y stand for S, Se, or Te) which are novel single-layer crystals. While all Janus structures are indirect band gap semiconductors as their binary analogues, their Raman spectra show distinctive features that stem from the broken out-of-plane symmetry. In addition, it is revealed that the construction of Janus crystals enhances the piezoelectric constants of PtX2 crystals significantly both in the in plane and in the out-of-plane directions. Moreover, it is shown that vertically stacked van der Waals heterostructures of binary and ternary (Janus) platinum dichalcogenides offer a wide range of electronic features by forming bilayer heterojunctions of type-I, type-II, and type-III, respectively. Our findings reveal that Janus-type ultrathin platinum dichalcogenide crystals are quite promising materials for optoelectronic device applications.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000459836900071	Publication Date	2019-01-24
	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	20	Open Access
	Notes	; Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure). H.S. and Z.K. acknowledge financial support from the TUBITAK under the project number 117F095. This work is supported by the Flemish Science Foundation (FWO-Vl) by a post-doctoral fellowship (M.Y.). H.S. acknowledges support from Turkiye Bilimler Akademisi-Turkish Academy of Sciences under the GEBIP program. ;			Approved	Most recent IF: 4.536
	Call Number	UA @ admin @ c:irua:158617			Serial	5229
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	Author	Eren, I.; Ozen, S.; Sozen, Y.; Yagmurcukardes, M.; Sahin, H.
	Title	Vertical van der Waals heterostructure of single layer InSe and SiGe			Type	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	Kandemir, A.; Peeters, F.M.; Sahin, H.
	Title	Monitoring the effect of asymmetrical vertical strain on Janus single layers of MoSSe via spectrum			Type	A1 Journal article
	Year	2018	Publication	The journal of chemical physics	Abbreviated Journal	J Chem Phys
	Volume	149	Issue	8	Pages	084707
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	Using first principles calculations, we study the structural and phononic properties of the recently synthesized Janus type single layers of molybdenum dichalcogenides. The Janus MoSSe single layer possesses 2H crystal structure with two different chalcogenide sides that lead to out-of-plane anisotropy. By virtue of the asymmetric structure of the ultra-thin Janus type crystal, we induced the out-of-plane anisotropy to show the distinctive vertical pressure effect on the vibrational properties of the Janus material. It is proposed that for the corresponding Raman active optical mode of the Janus structure, the phase modulation and the magnitude ratio of the strained atom and its first neighbor atom adjust the distinctive change in the eigen-frequencies and Raman activity. Moreover, a strong variation in the Raman activity of the Janus structure is obtained under bivertical and univertical strains. Not only eigen-frequency shifts but also Raman activities of the optical modes of the Janus structure exhibit distinguishable features. This study reveals that the vertical anisotropic feature of the Janus structure under Raman measurement allows us to distinguish which side of the Janus crystal interacts with the externals (substrate, functional adlayers, or dopants). Published by AIP Publishing.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	New York, N.Y.	Editor
	Language		Wos	000444035800044	Publication Date	2018-08-30
	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	2.965	Times cited	11	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 TUBITAK under Project No. 117F095. F.M.P. was supported by the FLAG-ERA-TRANS<INF>2D</INF>TMD. ;			Approved	Most recent IF: 2.965
	Call Number	UA @ lucian @ c:irua:153711UA @ admin @ c:irua:153711			Serial	5115
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	Author	Baskurt, M.; Yagmurcukardes, M.; Peeters, F.M.; Sahin, H.
	Title	Stable single-layers of calcium halides (CaX₂, X = F, Cl, Br, I)			Type	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	Ghosh, S.; Tongay, S.; Hebard, A.F.; Sahin, H.; Peeters, F.M.
	Title	Ferromagnetism in stacked bilayers of Pd/C₆₀			Type	A1 Journal article
	Year	2014	Publication	Journal of magnetism and magnetic materials	Abbreviated Journal	J Magn Magn Mater
	Volume	349	Issue		Pages	128-134
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	We provide experimental evidence for the existence of ferromagnetism in bilayers of Pd/C-60 which is supported by theoretical calculations based on density functional theory (DFT). The observed ferromagnetism is surprising as C-60 and Pd films are both non-ferromagnetic in the non-interacting limit. Magnetization (M) versus applied field (H) data acquired at different temperatures (T) show magnetic hysteresis with typical coercive fields (H-c) on the order of 50 Oe. From the temperature-dependent magnetization M(T) we extract a Curie temperature (T-c >= 550 K) using Bloch-like power law extrapolations to high temperatures. Using DFT calculations we investigated all plausible scenarios for the interaction between the C-60 molecules and the Pd slabs, Pd single atoms and Pd clusters. DFT shows that while the C-60 molecules are nonmagnetic, Pd films have a degenerate ground state that subject to a weak perturbation, can become ferromagnetic. Calculations also show that the interaction of C-60 molecules with excess Pd atoms and with sharp edges of a Pd slab is the most likely configuration that render the system ferromagnetic Interestingly, the calculated charge transfer (0.016 e per surface Pd atom, 0.064 e per Pd for intimate contact region) between C-60 and Pd does not appear to play an important role. (C) 2013 Elsevier B.V. All rights reserved.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Amsterdam	Editor
	Language		Wos	000326037600022	Publication Date	2013-08-02
	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	2.63	Times cited	8	Open Access
	Notes	; We thank Prof. Amlan Biswas and Daniel Grant for Atomic Force Microscopy measurements. This work is supported by the National Science Foundation (NSF) under Contract Number 1005301 (AFH). The authors also thank S. Ciraci for fruitful discussions. All the computational resources have been provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure). H. Sahin is also supported by a FWO Pegasus Marie Curie Long Fellowship during the study. ;			Approved	Most recent IF: 2.63; 2014 IF: 1.970
	Call Number	UA @ lucian @ c:irua:112214			Serial	1184
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	Author	Aydin, H.; Bacaksiz, C.; Yagmurcukardes, N.; Karakaya, C.; Mermer, O.; Can, M.; Senger, R.T.; Sahin, H.; Selamet, Y.
	Title	Experimental and computational investigation of graphene/SAMs/n-Si Schottky diodes			Type	A1 Journal article
	Year	2018	Publication	Applied Surface Science	Abbreviated Journal	Appl Surf Sci
	Volume	428	Issue	428	Pages	1010-1017
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	We have investigated the effect of two different self-assembled monolayers (SAMs) on electrical characteristics of bilayer graphene (BLG)/n-Si Schottky diodes. Novel 4“bis(diphenylamino)-1, 1':3”-terpheny1-5' carboxylic acids (TPA) and 4,4-di-9H-carbazol-9-y1-1,1':3'1'-terpheny1-5' carboxylic acid (CAR) aromatic SAMs have been used to modify n-Si surfaces. Cyclic voltammetry (CV) and Kelvin probe force microscopy (KPFM) results have been evaluated to verify the modification of n-Si surface. The current-voltage (I-V) characteristics of bare and SAMs modified devices show rectification behaviour verifying a Schottky junction at the interface. The ideality factors (n) from ln(I)-V dependences were determined as 2.13,1.96 and 2.07 for BLG/n-Si, BLG/TPA/n-Si and BLG/CAR/n-Si Schottky diodes, respectively. In addition, Schottky barrier height (SBH) and series resistance (Rs) of SAMs modified diodes were decreased compared to bare diode due to the formation of a compatible interface between graphene and Si as well as n-n interaction between aromatic SAMs and graphene. The CAR-based device exhibits better diode characteristic compared to the TPA-based device. Computational simulations show that the BLG/CAR system exhibits smaller energy-level-differences than the BLG/TPA, which supports the experimental findings of a lower Schottky barrier and series resistance in BLG/CAR diode. (C) 2017 Elsevier B.V. All rights reserved.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Amsterdam	Editor
	Language		Wos	000415227000128	Publication Date	2017-09-29
	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	2	Open Access
	Notes	; This work was supported by TUBITAK (The Scientific and Technical Research Council of Turkey) with project number 112T946. We also thank AQuReC (Applied Quantum Research Center) for Raman measurements. Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure). H.S. acknowledges support from Bilim Akademisi The Science Academy, Turkey under the BAGEP program. ;			Approved	Most recent IF: 3.387
	Call Number	UA @ lucian @ c:irua:154608UA @ admin @ c:irua:154608			Serial	5101
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	Author	Ozcan, M.; Ozen, S.; Yagmurcukardes, M.; Sahin, H.
	Title	Structural, electronic and vibrational properties of ultra-thin octahedrally coordinated structure of EuO₂			Type	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	Sozen, Y.; Eren, I.; Ozen, S.; Yagmurcukardes, M.; Sahin, H.
	Title	Interaction of Ge with single layer GaAs : from Ge-island nucleation to formation of novel stable monolayers			Type	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	Baskurt, M.; Eren, I.; Yagmurcukardes, M.; Sahin, H.
	Title	Vanadium dopant- and strain-dependent magnetic properties of single-layer VI₃			Type	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	Ozaydin, H.D.; Sahin, H.; Senger, R.T.; Peeters, F.M.
	Title	Formation and diffusion characteristics of Pt clusters on Graphene, 1H-MoS2 and 1T-TaS2			Type	A1 Journal article
	Year	2014	Publication	Annalen der Physik	Abbreviated Journal	Ann Phys-Berlin
	Volume	526	Issue	9-10	Pages	423-429
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	Many experiments have revealed that the surfaces of graphene and graphene-like structures can play an active role as a host surface for clusterization of transition metal atoms. Motivated by these observations, we investigate theoretically the adsorption, diffusion and magnetic properties of Pt clusters on three different two-dimensional atomic crystals using first principles density functional theory. We found that monolayers of graphene, molybdenum disulfide (1H-MoS2) and tantalum disulfide (1T-TaS2) provide different nucleation characteristics for Pt cluster formation. At low temperatures, while the bridge site is the most favorable site where the growth of a Pt cluster starts on graphene, top-Mo and top-Ta sites are preferred on 1H-MoS2 and 1T-TaS2, respectively. Ground state structures and magnetic properties of Pt-n clusters (n= 2,3,4) on three different monolayer crystal structures are obtained. We found that the formation of Pt-2 dimer and a triangle-shaped Pt-3 cluster perpendicular to the surface are favored over the three different surfaces. While bent rhombus shaped Pt-4 is formed on graphene, the formation of tetrahedral shaped clusters are more favorable on 1H-MoS2 and 1T-TaS2. Our study of the formation of Pt-n clusters on three different monolayers provides a gateway for further exploration of nanocluster formations on various surfaces.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Leipzig	Editor
	Language		Wos	000343873700015	Publication Date	2014-06-16
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0003-3804;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.039	Times cited	10	Open Access
	Notes	; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Methusalem foundation of the Flemish government. Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure). H.S. is supported by a FWO Pegasus Long Marie Curie Fellowship. ;			Approved	Most recent IF: 3.039; 2014 IF: 3.048
	Call Number	UA @ lucian @ c:irua:121180			Serial	1247
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	Author	Kahraman, Z.; Baskurt, M.; Yagmurcukardes, M.; Chaves, A.; Sahin, H.
	Title	Stable Janus TaSe₂ single-layers via surface functionalization			Type	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.
	Title	First-principles investigation of structural, Raman and electronic characteristics of single layer Ge3N4			Type	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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