| Records |
| Author |
Van der Donck, M.; Zarenia, M.; Peeters, F.M. |
| Title |
Excitons and trions in monolayer transition metal dichalcogenides : a comparative study between the multiband model and the quadratic single-band model |
Type |
A1 Journal article |
| Year |
2017 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
| Volume |
96 |
Issue |
3 |
Pages |
035131 |
| Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
| Abstract |
The electronic and structural properties of excitons and trions in monolayer transition metal dichalcogenides are investigated using both a multiband and a single- band model. In the multiband model we construct the excitonic Hamiltonian in the product base of the single-particle states at the conduction and valence band edges. We decouple the corresponding energy eigenvalue equation and solve the resulting differential equation self-consistently, using the finite element method (FEM), to determine the energy eigenvalues and the wave functions. As a comparison, we also consider the simple single-band model which is often used in numerical studies. We solve the energy eigenvalue equation using the FEM as well as with the stochastic variational method (SVM) in which a variational wave function is expanded in a basis of a large number of correlated Gaussians. We find good agreement between the results of both methods, as well as with other theoretical works for excitons, and we also compare with available experimental data. For trions the agreement between both methods is not as good due to our neglect of angular correlations when using the FEM. Finally, when comparing the two models, we see that the presence of the valence bands in the mutiband model leads to differences with the single- band model when (interband) interactions are strong. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
American Physical Society |
Place of Publication |
New York, N.Y |
Editor |
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| Language |
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Wos |
000405706600005 |
Publication Date |
2017-07-18 |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
2469-9969; 2469-9950 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
3.836 |
Times cited  |
50 |
Open Access |
|
| Notes |
; This work was supported by the Research Foundation of Flanders (FWO-Vl) through an aspirant research grant for MVDD. ; |
Approved |
Most recent IF: 3.836 |
| Call Number |
UA @ lucian @ c:irua:145209 |
Serial |
4716 |
| Permanent link to this record |
| |
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| |
| Author |
Stosic, D.; Ludermir, T.B.; Milošević, M.V. |
| Title |
Pinning of magnetic skyrmions in a monolayer Co film on Pt(111) : Theoretical characterization and exemplified utilization |
Type |
A1 Journal article |
| Year |
2017 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
| Volume |
96 |
Issue |
21 |
Pages |
214403 |
| Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
| Abstract |
<script type='text/javascript'>document.write(unpmarked('Magnetic skyrmions are nanoscale windings of the spin structure that can be observed in chiral magnets and hold promise for potential applications in storing or processing information. Pinning due to ever-present material imperfections crucially affects the mobility of skyrmions. Therefore, a proper understanding of how magnetic skyrmions pin to defects is necessary for the development and performance of spintronic devices. Here we present a fundamental analysis on the interactions of single skyrmions with atomic defects of distinctly different origins, in a Co monolayer on Pt, based on minimum-energy paths considerations and atomic-spin simulations. We first report the preferred pinning loci of the skyrmion as a function of its nominal size and the type of defect being considered, to further reveal the manipulation and \u0022breathing\u0022 of skyrmion core in the vicinity of a defect. We also show the behavior of skyrmions in the presence of an extended defect of particular geometry, that can lead to ratcheted skyrmion motion or a facilitated guidance on a defect \u0022trail.\u0022 We close the study with reflections on the expected thermal stability of the skyrmion against collapse on itself for a given nature of the defect, and discuss the applications where control of skyrmions by defects is of particular interest.')); |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
American Physical Society |
Place of Publication |
New York, N.Y |
Editor |
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| Language |
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Wos |
000416846900002 |
Publication Date |
2017-12-01 |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
2469-9969; 2469-9950 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
3.836 |
Times cited |
52 |
Open Access |
|
| Notes |
; This work was supported by the Research Foundation, Flanders (FWO-Vlaanderen) and Brazilian agency CNPq (Grants No. 442668/2014-7 and No. 140840/2016-8). ; |
Approved |
Most recent IF: 3.836 |
| Call Number |
UA @ lucian @ c:irua:147684 |
Serial |
4890 |
| Permanent link to this record |
| |
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| |
| Author |
Bekaert, J.; Aperis, A.; Partoens, B.; Oppeneer, P.M.; Milošević, M.V. |
| Title |
Evolution of multigap superconductivity in the atomically thin limit : strain-enhanced three-gap superconductivity in monolayer MgB2 |
Type |
A1 Journal article |
| Year |
2017 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
| Volume |
96 |
Issue |
9 |
Pages |
094510 |
| Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
| Abstract |
Starting from first principles, we show the formation and evolution of superconducting gaps in MgB2 at its ultrathin limit. Atomically thin MgB2 is distinctly different from bulk MgB2 in that surface states become comparable in electronic density to the bulklike sigma and pi bands. Combining the ab initio electron-phonon coupling with the anisotropic Eliashberg equations, we showthat monolayer MgB2 develops three distinct superconducting gaps, on completely separate parts of the Fermi surface due to the emergent surface contribution. These gaps hybridize nontrivially with every extra monolayer added to the film owing to the opening of additional coupling channels. Furthermore, we reveal that the three-gap superconductivity in monolayer MgB2 is robust over the entire temperature range that stretches up to a considerably high critical temperature of 20 K. The latter can be boosted to >50K under biaxial tensile strain of similar to 4%, which is an enhancement that is stronger than in any other graphene-related superconductor known to date. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
American Physical Society |
Place of Publication |
New York, N.Y |
Editor |
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| Language |
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Wos |
000410166800008 |
Publication Date |
2017-09-11 |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
2469-9969; 2469-9950 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
3.836 |
Times cited |
56 |
Open Access |
|
| Notes |
; This work was supported by TOPBOF-UAntwerp, Research Foundation-Flanders (FWO), the Swedish Research Council (VR), and the Rontgen-Angstrom Cluster. The first-principles calculations have been carried out on the HPC infrastructure of the University of Antwerp (CalcUA), a division of the Flemish Supercomputer Centre (VSC), supported financially by the Hercules Foundation and the Flemish Government (EWI Department). Eliashberg theory calculations were supported through the Swedish National Infrastructure for Computing (SNIC). ; |
Approved |
Most recent IF: 3.836 |
| Call Number |
UA @ lucian @ c:irua:145623 |
Serial |
4741 |
| Permanent link to this record |
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| |
| Author |
Mulkers, J.; Van Waeyenberge, B.; Milošević, M.V. |
| Title |
Effects of spatially engineered Dzyaloshinskii-Moriya interaction in ferromagnetic films |
Type |
A1 Journal article |
| Year |
2017 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
| Volume |
95 |
Issue |
95 |
Pages |
144401 |
| Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
| Abstract |
The Dzyaloshinskii-Moriya interaction (DMI) is a chiral interaction that favors formation of domain walls. Recent experiments and ab initio calculations show that there are multiple ways to modify the strength of the interfacially induced DMI in thin ferromagnetic films with perpendicular magnetic anisotropy. In this paper we reveal theoretically the effects of spatially varied DMI on the magnetic state in thin films. In such heterochiral 2D structures we report several emergent phenomena, ranging from the equilibrium spin canting at the interface between regions with different DMI, over particularly strong confinement of domain walls and skyrmions within high-DMI tracks, to advanced applications such as domain tailoring nearly at will, design of magnonic waveguides, and much improved skyrmion racetrack memory. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
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| Language |
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Wos |
000399382100003 |
Publication Date |
2017-04-03 |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
2469-9950 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
3.836 |
Times cited |
60 |
Open Access |
|
| Notes |
Fonds Wetenschappelijk Onderzoek, G098917N ; |
Approved |
Most recent IF: 3.836 |
| Call Number |
CMT @ cmt @ c:irua:141917 |
Serial |
4534 |
| Permanent link to this record |
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| Author |
Sisakht, E.T.; Fazileh, F.; Zare, M.H.; Zarenia, M.; Peeters, F.M. |
| Title |
Strain-induced topological phase transition in phosphorene and in phosphorene nanoribbons |
Type |
A1 Journal article |
| Year |
2016 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
| Volume |
94 |
Issue |
94 |
Pages |
085417 |
| Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
| Abstract |
Using the tight-binding (TB) approximation with inclusion of the spin-orbit interaction, we predict a topological phase transition in the electronic band structure of phosphorene in the presence of axial strains. We derive a low-energy TB Hamiltonian that includes the spin-orbit interaction for bulk phosphorene. Applying a compressive biaxial in-plane strain and perpendicular tensile strain in ranges where the structure is still stable leads to a topological phase transition. We also examine the influence of strain on zigzag phosphorene nanoribbons (zPNRs) and the formation of the corresponding protected edge states when the system is in the topological phase. For zPNRs up to a width of 100 nm the energy gap is at least three orders of magnitude larger than the thermal energy at room temperature. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
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| Language |
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Wos |
000381600800004 |
Publication Date |
2016-08-18 |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
2469-9950;2469-9969; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
3.836 |
Times cited |
76 |
Open Access |
|
| Notes |
; This work was supported by Ministry of Science, Research and Technology, Iran. M.Z. acknowledges support as a postdoctoral fellow of the Flemish Research Foundation (FWO-Vl). ; |
Approved |
Most recent IF: 3.836 |
| Call Number |
UA @ lucian @ c:irua:135643 |
Serial |
4309 |
| Permanent link to this record |
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| Author |
Yagmurcukardes, M.; Sevik, C.; Peeters, F.M. |
| Title |
Electronic, vibrational, elastic, and piezoelectric properties of monolayer Janus MoSTe phases: A first-principles study |
Type |
A1 Journal article |
| Year |
2019 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
| Volume |
100 |
Issue |
4 |
Pages |
045415 |
| Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
| Abstract |
By performing density functional theory based first-principles calculations, the electronic, vibrational, elastic, and piezoelectric properties of two dynamically stable crystal phases of monolayer Janus MoSTe, namely 1H-MoSTe and 1T'-MoSTe, are investigated. Vibrational frequency analysis reveals that the other possible crystal structure, 1T-MoSTe, of this Janus monolayer does not exhibit dynamical stability. The 1H-MoSTe phase is found to be an indirect band-gap semiconductor while 1T'-MoSTe is predicted as small-gap semiconductor. Notably, in contrast to the direct band-gap nature of monolayers 1H-MoS2 and 1H-MoTe2, 1H-MoSTe is found to be an indirect gap semiconductor driven by the induced surface strains on each side of the structure. The calculated Raman spectrum of each structure shows unique character enabling us to clearly distinguish the stable crystal phases via Raman measurements. The systematic piezoelectric stress and strain coefficient analysis reveals that out-of-plane piezoelectricity appears in 1H-MoSTe and the noncentral symmetric 1T'-MoSTe has large piezoelectric coefficients. Static total-energy calculations show clearly that the formation of 1T'-MoSTe is feasible by using 1T'-MoTe2 as a basis monolayer. Therefore, we propose that the Janus MoSTe structure can be fabricated in two dynamically stable phases which possess unique electronic, dynamical, and piezoelectric properties. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
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| Language |
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Wos |
000476687800003 |
Publication Date |
2019-07-19 |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
2469-9969; 2469-9950 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
3.836 |
Times cited |
91 |
Open Access |
|
| Notes |
; Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure). This work was supported by the Flemish Science Foundation (FWO-Vl) by a postdoctoral fellowship (M.Y.). ; |
Approved |
Most recent IF: 3.836 |
| Call Number |
UA @ admin @ c:irua:161899 |
Serial |
5411 |
| Permanent link to this record |
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| Author |
Yagmurcukardes, M.; Senger, R.T.; Peeters, F.M.; Sahin, H. |
| Title |
Mechanical properties of monolayer GaS and GaSe crystals |
Type |
A1 Journal article |
| Year |
2016 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
| Volume |
94 |
Issue |
94 |
Pages |
245407 |
| Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
| Abstract |
The mechanical properties of monolayer GaS and GaSe crystals are investigated in terms of their elastic constants: in-plane stiffness (C), Poisson ratio (nu), and ultimate strength (sigma(U)) by means of first-principles calculations. The calculated elastic constants are compared with those of graphene and monolayer MoS2. Our results indicate that monolayer GaS is a stiffer material than monolayer GaSe crystals due to the more ionic character of the Ga-S bonds than the Ga-Se bonds. Although their Poisson ratio values are very close to each other, 0.26 and 0.25 for GaS and GaSe, respectively, monolayer GaS is a stronger material than monolayer GaSe due to its slightly higher sU value. However, GaS and GaSe crystals are found to be more ductile and flexible materials than graphene and MoS2. We have also analyzed the band-gap response of GaS and GaSe monolayers to biaxial tensile strain and predicted a semiconductor-metal crossover after 17% and 14% applied strain, respectively, for monolayer GaS and GaSe. In addition, we investigated how the mechanical properties are affected by charging. We found that the flexibility of single layer GaS and GaSe displays a sharp increase under 0.1e/cell charging due to the repulsive interactions between extra charges located on chalcogen atoms. These charging-controllable mechanical properties of single layers of GaS and GaSe can be of potential use for electromechanical applications. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
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| Language |
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Wos |
000389503400008 |
Publication Date |
2016-12-05 |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
2469-9950;2469-9969; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
3.836 |
Times cited |
108 |
Open Access |
|
| Notes |
; Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure). H.S. acknowledges support from Bilim Akademisi-The Science Academy, Turkey under the BAGEP program. R.T.S. acknowledges the support from TUBITAK through project 114F397. ; |
Approved |
Most recent IF: 3.836 |
| Call Number |
UA @ lucian @ c:irua:139229 |
Serial |
4356 |
| Permanent link to this record |
