| Records |
| Author |
Vishwakarma, M.; Varandani, D.; Hendrickx, M.; Hadermann, J.; Mehta, B.R. |
| Title |
Nanoscale photovoltage mapping in CZTSe/CuxSe heterostructure by using kelvin probe force microscopy |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Materials Research Express |
Abbreviated Journal |
|
| Volume |
7 |
Issue |
1 |
Pages |
016418 |
Keywords  |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
In the present work, kelvin probe force microscopy (KPFM) technique has been used to study the CZTSe/CuxSe bilayer interface prepared by multi-step deposition and selenization process of metal precursors. Transmission electron microscopy (TEM) confirmed the bilayer configuration of the CZTSe/CuxSe sample. Two configuration modes (surface mode and junction mode) in KPFM have been employed in order to measure the junction voltage under illumination conditions. The results show that CZTSe/CuxSe has small junction voltage of similar to 21 mV and the presence of CuxSe secondary phase in the CZTSe grain boundaries changes the workfunction of the local grain boundaries region. The negligible photovoltage difference between grain and grain boundaries in photovoltage image indicates that CuxSe phase deteriorates the higher photovoltage at grain boundaries normally observed in CZTSe based device. These results can be important for understanding the role of secondary phases in CZTSe based junction devices. |
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| Corporate Author |
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Thesis |
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Place of Publication |
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Editor |
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| Language |
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Wos |
000520120900001 |
Publication Date |
2019-12-27 |
| 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 |
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ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
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Times cited |
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Open Access |
OpenAccess |
| Notes |
; Authors acknowledges support provided DST in the forms of InSOL and Indo-Swiss projects. We also acknowledge Joke Hadermann EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Belgium for helping in TEM measurements. M V Manoj Vishwakarma acknowledges IIT Delhi for MHRD fellowship. Prof B R Mehta acknowledges the support of the Schlumberger chair professorship. M V also acknowledges the support of DST-FIST Raman facility. ; |
Approved |
Most recent IF: NA |
| Call Number |
UA @ admin @ c:irua:167843 |
Serial |
6567 |
| Permanent link to this record |
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| |
| Author |
Parsons, T.G.; Hadermann, J.; Halasyamani, P.S.; Hayward, M.A. |
| Title |
Preparation of the noncentrosymmetric ferrimagnetic phase La0.9Ba0.1Mn0.96O2.43 by topochemical reduction |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Journal Of Solid State Chemistry |
Abbreviated Journal |
J Solid State Chem |
| Volume |
287 |
Issue |
|
Pages |
121356-121357 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
Topochemical reduction of La0.9Ba0.1MnO3 with NaH at 225 degrees C yields the brownmillerite phase La0.9Ba0.1MnO2.5. However, reduction with CaH2 at 435 degrees C results in the formation of La0.9Ba0.1Mn0.96O2.43 via the deintercalation of both oxide anions and manganese cations from the parent perovskite phase. Electron and neutron diffraction data reveal La0.9Ba0.1Mn0.96O2.43 adopts a complex noncentrosymmetric structure, described in space group I23, confirmed by SHG measurements. Low-temperature neutron diffraction data reveal La0.9Ba0.1Mn0.96O2.43 adopts an ordered magnetic structure in which all the nearest neighbor interactions are antiferromagnetic. However, the presence of ordered manganese cation-vacancies results in a net ferrimagnetic structure with net saturated moment of 0.157(2) mu B per manganese center. |
| 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 |
000533632700029 |
Publication Date |
2020-04-05 |
| 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 |
|
Edition |
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| ISSN |
0022-4596 |
ISBN |
|
Additional Links |
UA library record; WoS full record |
| Impact Factor |
3.3 |
Times cited |
|
Open Access |
Not_Open_Access |
| Notes |
; We thank the EPSRC for funding this work and E. Suard for assisting with the collection of the neutron powder diffraction data. PSH thanks the Welch Foundation (Grant E-1457) for support. ; |
Approved |
Most recent IF: 3.3; 2020 IF: 2.299 |
| Call Number |
UA @ admin @ c:irua:169450 |
Serial |
6583 |
| Permanent link to this record |
| |
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| |
| Author |
Liu, P.; Madsen, J.; Schiotz, J.; Wagner, J.B.; Hansen, T.W. |
| Title |
Reversible and concerted atom diffusion on supported gold nanoparticles |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Journal Of Physics-materials |
Abbreviated Journal |
|
| Volume |
3 |
Issue |
2 |
Pages |
024009 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
Traditionally, direct imaging of atom diffusion is only available by scanning tunneling microscopy and field ion microscopy on geometry-constrained samples: flat surfaces for STM and needle tips for FIM. Here we show time-resolved atomic-scale HRTEM investigations of CeO2-supported Au nanoparticle surfaces to characterize the surface dynamics of atom columns on gold nanoparticles. The observed surface dynamics have been categorized into four types: layer jumping, layer gliding, re-orientation and surface reconstruction. We successfully captured atoms moving in a concerted manner with a time resolution of 0.1 s. A quantitative approach for measuring the dynamics in various gaseous surroundings at elevated temperatures is presented. An approach for measuring quantitative electron beam effects on the surface dynamics is presented by counting atom column occupation as a function of time under a range of dose rates in high vacuum. |
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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 |
000560432800009 |
Publication Date |
2020-03-24 |
| 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 |
|
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
|
Times cited |
2 |
Open Access |
OpenAccess |
| Notes |
; ; |
Approved |
Most recent IF: NA |
| Call Number |
UA @ admin @ c:irua:171320 |
Serial |
6597 |
| Permanent link to this record |
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| |
| Author |
Van Velthoven, N.; Henrion, M.; Dallenes, J.; Krajnc, A.; Bugaev, A.L.; Liu, P.; Bals, S.; Soldatov, A.; Mali, G.; De Vos, D.E. |
| Title |
S,O-functionalized metal-organic frameworks as heterogeneous single-site catalysts for the oxidative alkenylation of arenes via C- H activation |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Acs Catalysis |
Abbreviated Journal |
Acs Catal |
| Volume |
10 |
Issue |
9 |
Pages |
5077-5085 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
Heterogeneous single-site catalysts can combine the R precise active site design of organometallic complexes with the efficient recovery of solid catalysts. Based on recent progress on homogeneous thioether ligands for Pd-catalyzed C-H activation reactions, we here develop a scalable metal-organic framework-based heterogeneous single-site catalyst containing S,O-moieties that increase the catalytic activity of Pd(II) for the oxidative alkenylation of arenes. The structure of the Pd@MOF-808-L1 catalyst was characterized in detail via solid-state nuclear magnetic resonance spectroscopy, N-2 physisorption, and high-angle annular dark field scanning transmission electron microscopy, and the structure of the isolated palladium active sites could be identified by X-ray absorption spectroscopy. A turnover frequency (TOF) of 8.4 h(-1) was reached after 1 h of reaction time, which was 3 times higher than the TOF of standard Pd(OAc)(2), ranking Pd@MOF-808-L1 among the most active heterogeneous catalysts ever reported for the nondirected oxidative alkenylation of arenes. Finally, we showed that the single-site catalyst promotes the oxidative alkenylation of a broad range of electron-rich arenes, and the applicability of this heterogeneous system was demonstrated by the gram-scale synthesis of industrially relevant products. |
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| Corporate Author |
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Thesis |
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Place of Publication |
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Editor |
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| Language |
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Wos |
000530090800026 |
Publication Date |
2020-04-06 |
| 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 |
|
Edition |
|
| ISSN |
2155-5435 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
12.9 |
Times cited |
37 |
Open Access |
OpenAccess |
| Notes |
; The research leading to these results has received funding from the NMBP-01-2016 Program of the European Union's Horizon 2020 Framework Program H2020/2014-2020/under grant agreement no [720996]. N.V.V. and D.E.D.V. thank the FWO for funding (1S32917N and G0F2320N). D.E.D.V. is grateful for KU Leuven's support in the frame of the CASAS Metusalem project and a C3 type project. A.K. and G.M. acknowledge the financial support from the Slovenian Research Agency (research core funding no. P1-0021 and project no. N1-0079). A.L.B and A.V.S. acknowledge Russian Science Foundation grant no. 20-43-01015 for financial support. We thank Alexander Trigub and Alexey Veligzhanin for their support during the beamtime at Kurchatov Institute. We are indebted to Elizaveta Kamyshova and Anna Pnevskaya for their valuable help during EXAFS measurements. P.L. and S.B. thank European Research Council for the ERC Consolidator Grant 815128, REALNANO. Kassem Amro and Guillaume Gracy from Sikemia are gratefully acknowledged for providing ; sygma |
Approved |
Most recent IF: 12.9; 2020 IF: 10.614 |
| Call Number |
UA @ admin @ c:irua:169530 |
Serial |
6598 |
| Permanent link to this record |
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| |
| Author |
Petrishcheva, E.; Tiede, L.; Schweinar, K.; Habler, G.; Li, C.; Gault, B.; Abart, R. |
| Title |
Spinodal decomposition in alkali feldspar studied by atom probe tomography |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Physics And Chemistry Of Minerals |
Abbreviated Journal |
Phys Chem Miner |
| Volume |
47 |
Issue |
7 |
Pages |
Unsp 30 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
We used atom probe tomography to complement electron microscopy for the investigation of spinodal decomposition in alkali feldspar. To this end, gem-quality alkali feldspar of intermediate composition with a mole fraction of a(K) = 0.43 of the K end-member was prepared from Madagascar orthoclase by ion-exchange with (NaK)Cl molten salt. During subsequent annealing at 550 degrees C and close to ambient pressure the ion-exchanged orthoclase unmixed producing a coherent lamellar intergrowth of Na-rich and K-rich lamellae. The chemical separation was completed, and equilibrium Na-K partitioning between the different lamellae was attained within four days, which was followed by microstructural coarsening. After annealing for 4 days, the wavelength of the lamellar microstructure was approximate to 17 nm and it increased to approximate to 30 nm after annealing for 16 days. The observed equilibrium compositions of the Na-rich and K-rich lamellae are in reasonable agreement with an earlier experimental determination of the coherent solvus. The excess energy associated with compositional gradients at the lamellar interfaces was quantified from the initial wavelength of the lamellar microstructure and the lamellar compositions as obtained from atom probe tomography using the Cahn-Hilliard theory. The capability of atom probe tomography to deliver quantitative chemical compositions at nm resolution opens new perspectives for studying the early stages of exsolution. In particular, it helps to shed light on the phase relations in nm scaled coherent intergrowth. |
| 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 |
000540150400001 |
Publication Date |
2020-06-07 |
| 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 |
0342-1791 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
1.4 |
Times cited |
|
Open Access |
OpenAccess |
| Notes |
; Open access funding provided by Austrian Science Fund (FWF). This project was funded by the FWF Project P28238-N29. KS acknowledges IMPRS-SurMat for funding. Uwe Tezins, Andreas Sturm and Christian Bross are acknowledged for their support at the FIB & APT facilities at MPIE. We gratefully acknowledge the thorough and constructive reviews by Herbert Kroll and Luis Sanchez Munoz, who substantially contributed to improving an earlier version of the manuscript. ; |
Approved |
Most recent IF: 1.4; 2020 IF: 1.521 |
| Call Number |
UA @ admin @ c:irua:170208 |
Serial |
6611 |
| Permanent link to this record |
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| Author |
Wang, H.S.; Chen, L.; Elibol, K.; He, L.; Wang, H.; Chen, C.; Jiang, C.; Li, C.; Wu, T.; Cong, C.X.; Pennycook, T.J.; Argentero, G.; Zhang, D.; Watanabe, K.; Taniguchi, T.; Wei, W.; Yuan, Q.; Meyer, J.C.; Xie, X. |
| Title |
Towards chirality control of graphene nanoribbons embedded in hexagonal boron nitride |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Nature Materials |
Abbreviated Journal |
Nat Mater |
| Volume |
|
Issue |
|
Pages |
1-10 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
Oriented trenches are created in h-BN using different catalysts, and used as templates to grow seamlessly integrated armchair and zigzag graphene nanoribbons with chirality-dependent electrical and magnetic conductance properties. The integrated in-plane growth of graphene nanoribbons (GNRs) and hexagonal boron nitride (h-BN) could provide a promising route to achieve integrated circuitry of atomic thickness. However, fabrication of edge-specific GNRs in the lattice of h-BN still remains a significant challenge. Here we developed a two-step growth method and successfully achieved sub-5-nm-wide zigzag and armchair GNRs embedded in h-BN. Further transport measurements reveal that the sub-7-nm-wide zigzag GNRs exhibit openings of the bandgap inversely proportional to their width, while narrow armchair GNRs exhibit some fluctuation in the bandgap-width relationship. An obvious conductance peak is observed in the transfer curves of 8- to 10-nm-wide zigzag GNRs, while it is absent in most armchair GNRs. Zigzag GNRs exhibit a small magnetic conductance, while armchair GNRs have much higher magnetic conductance values. This integrated lateral growth of edge-specific GNRs in h-BN provides a promising route to achieve intricate nanoscale circuits. |
| 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 |
000571692500001 |
Publication Date |
2020-09-21 |
| 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 |
1476-1122; 1476-4660 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
41.2 |
Times cited |
3 |
Open Access |
Not_Open_Access |
| Notes |
; H.W. and X.X. thank J.H. Edgar (Kansas State University, USA) for supplying the partial h-BN crystals. H. S. Wang, L. Chen and H. Wang thank M. Liu, X. Qiu and J. Pan from NCNT of China, F. Liou, H. Tsai, M. Crommie from UCB, USA, J. Xue and P. Yu from ShanghaiTech University and S. Wang from SJTU for nc-AFM measurement. H. S. Wang, L. Chen and H. Wang thank B. Sun and S. Li from Hunan University for the fusion of the STEM image and the electron energy loss spectroscopy mapping images. Funding: The work was partially supported by the National Key R&D program (Grant No. 2017YFF0206106), the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDB30000000), the National Science Foundation of China (Grant No. 51772317, 51302096, 61774040, 91964102), the Science and Technology Commission of Shanghai Municipality (Grant No. 16ZR1442700, 16ZR1402500 18511110700), Shanghai Rising-Star Program (A type) (Grant No.18QA1404800), the Hubei Provincial Natural Science Foundation of China (Grant No. ZRMS2017000370), China Postdoctoral Science Foundation (Grant No. 2017M621563, 2018T110415), and the Fundamental Research Funds of Wuhan City (No. 2016060101010075). C.L. acknowledges support from the European Union's Horizon 2020 research and innovation programme under the Marie Skodowska-Curie grants No. 656378 – Interfacial Reactions. T.J.P. acknowledges funding from European Union's Horizon 2020 Research and Innovation Programme under the Marie Sklodowska-Curie grant agreement no. 655760-DIGIPHASE. K.W. and T.T. acknowledge support from the Elemental Strategy Initiative conducted by the MEXT, Japan and the CREST (JPMJCR15F3), JST. C.X.C. acknowledges financial support from the National Young 1000 Talent Plan of China and the National Key R&D Program of China (No. 2018YFA0703700). L.H. acknowledges financial support from the programme of China Scholarships Council (No. 201706160037). ; |
Approved |
Most recent IF: 41.2; 2020 IF: 39.737 |
| Call Number |
UA @ admin @ c:irua:171944 |
Serial |
6633 |
| Permanent link to this record |
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| Author |
Pourbabak, S.; Orekhov, A.; Schryvers, D. |
| Title |
Twin-jet electropolishing for damage-free transmission electron microscopy specimen preparation of metallic microwires |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Microscopy Research And Technique |
Abbreviated Journal |
Microsc Res Techniq |
| Volume |
|
Issue |
|
Pages |
1-7 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
A method to prepare TEM specimens from metallic microwires and based on conventional twin-jet electropolishing is introduced. The wire is embedded in an opaque epoxy resin medium and the hardened resin is mechanically polished to reveal the wire on both sides. The resin containing wire is then cut into discs of the appropriate size. The obtained embedded wire is electropolished in a conventional twin-jet electropolishing machine until electron transparency in large areas without radiation damage is achieved. |
| 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 |
000567944200001 |
Publication Date |
2020-09-28 |
| 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 |
|
Edition |
|
| ISSN |
1059-910x |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.5 |
Times cited |
|
Open Access |
OpenAccess |
| Notes |
; Fonds Wetenschappelijk Onderzoek, Grant/Award Number: G.0366.15N ; |
Approved |
Most recent IF: 2.5; 2020 IF: 1.147 |
| Call Number |
UA @ admin @ c:irua:171969 |
Serial |
6642 |
| Permanent link to this record |
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| Author |
Jorgensen, M.; Shea, P.T.; Tomich, A.W.; Varley, J.B.; Bercx, M.; Lovera, S.; Cerny, R.; Zhou, W.; Udovic, T.J.; Lavallo, V.; Jensen, T.R.; Wood, B.C.; Stavila, V. |
| Title |
Understanding superionic conductivity in lithium and sodium salts of weakly coordinating closo-hexahalocarbaborate anions |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Chemistry of materials |
Abbreviated Journal |
|
| Volume |
32 |
Issue |
4 |
Pages |
1475-1487 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
Solid-state ion conductors based on closo-polyborate anions combine high ionic conductivity with a rich array of tunable properties. Cation mobility in these systems is intimately related to the strength of the interaction with the neighboring anionic network and the energy for reorganizing the coordination polyhedra. Here, we explore such factors in solid electrolytes with two anions of the weakest coordinating ability, [HCB11H5Cl6](-) and [HCB11H5Br6](-), and a total of 11 polymorphs are identified for their lithium and sodium salts. Our approach combines ab initio molecular dynamics, synchrotron X-ray powder diffraction, differential scanning calorimetry, and AC impedance measurements to investigate their structures, phase-transition behavior, anion orientational mobilities, and ionic conductivities. We find that M(HCB11H5X6) (M = Li, Na, X = Cl, Br) compounds exhibit order-disorder polymorphic transitions between 203 and 305 degrees C and display Li and Na superionic conductivity in the disordered state. Through detailed analysis, we illustrate how cation disordering in these compounds originates from a competitive interplay among the lattice symmetry, the anion reorientational mobility, the geometric and electronic asymmetry of the anion, and the polarizability of the halogen atoms. These factors are compared to other closo-polyborate-based ion conductors to suggest guidelines for optimizing the cation-anion interaction for fast ion mobility. This study expands the known solid-state poly(carba)borate-based materials capable of liquid-like ionic conductivities, unravels the mechanisms responsible for fast ion transport, and provides insights into the development of practical superionic solid electrolytes. |
| Address |
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Thesis |
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Place of Publication |
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Editor |
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Wos |
000517351300014 |
Publication Date |
2020-01-23 |
| 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 |
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ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
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Times cited |
5 |
Open Access |
OpenAccess |
| Notes |
; The authors gratefully acknowledge support from the Hydrogen Materials-Advanced Research Consortium (HyMARC), established as part of the Energy Materials Network under the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Fuel Cell Technologies Office, under Contract no. AC04-94AL85000. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy's National Nuclear Security Administration under Contract no. DE-NA-0003525. A portion of this work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract no. ACS2-07NA27344. We also gratefully thank Kyoung Kweon for useful discussions. The views and opinions of the authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. Neither the United States Government nor any agency thereof nor any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. The Danish council for independent research, technology and production, HyNanoBorN (4181-00462) and SOS-MagBat (9041-00226B) and NordForsk, The Nordic Neutron Science Program, project FunHy (81942), and the Carlsberg Foundation are acknowledged for funding. Affiliation with the Center for Integrated Materials Research (iMAT) at Aarhus University is gratefully acknowledged. V.L. acknowledges the NSF for partial support of this project (DMR-1508537). The authors would like to thank the Swiss-Norwegian beamlines (BM01) at the ESRF, Grenoble, for the help with the data collection, DESY for access to Petra III, at beamline P02.1, and Diamond for access to beamline I11. ; |
Approved |
Most recent IF: NA |
| Call Number |
UA @ admin @ c:irua:167754 |
Serial |
6645 |
| Permanent link to this record |
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| Author |
Han, Y.; Zeng, Y.; Hendrickx, M.; Hadermann, J.; Stephens, P.W.; Zhu, C.; Grams, C.P.; Hemberger, J.; Frank, C.; Li, S.; Wu, M.X.; Retuerto, M.; Croft, M.; Walker, D.; Yao, D.-X.; Greenblatt, M.; Li, M.-R. |
| Title |
Universal a-cation splitting in LiNbO₃-type structure driven by intrapositional multivalent coupling |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Journal Of The American Chemical Society |
Abbreviated Journal |
J Am Chem Soc |
| Volume |
142 |
Issue |
15 |
Pages |
7168-7178 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
Understanding the electric dipole switching in multiferroic materials requires deep insight of the atomic-scale local structure evolution to reveal the ferroelectric mechanism, which remains unclear and lacks a solid experimental indicator in high-pressure prepared LiNbO3-type polar magnets. Here, we report the discovery of Zn-ion splitting in LiNbO3-type Zn2FeNbO6 established by multiple diffraction techniques. The coexistence of a high-temperature paraelectric-like phase in the polar Zn2FeNbO6 lattice motivated us to revisit other high-pressure prepared LiNbO3-type A(2)BB'O-6 compounds. The A-site atomic splitting (similar to 1.0-1.2 angstrom between the split-atom pair) in B/B'-mixed Zn2FeTaO6 and O/N-mixed ZnTaO2N is verified by both powder X-ray diffraction structural refinements and high angle annular dark field scanning transmission electron microscopy images, but is absent in single-B-site ZnSnO3. Theoretical calculations are in good agreement with experimental results and suggest that this kind of A-site splitting also exists in the B-site mixed Mn-analogues, Mn2FeMO6 (M = Nb, Ta) and anion-mixed MnTaO2N, where the smaller A-site splitting (similar to 0.2 angstrom atomic displacement) is attributed to magnetic interactions and bonding between A and B cations. These findings reveal universal A-site splitting in LiNbO3-type structures with mixed multivalent B/B', or anionic sites, and the splitting-atomic displacement can be strongly suppressed by magnetic interactions and/or hybridization of valence bands between d electrons of the A- and B-site cations. |
| 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 |
000526300600046 |
Publication Date |
2020-03-27 |
| 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 |
0002-7863 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
15 |
Times cited |
1 |
Open Access |
Not_Open_Access |
| Notes |
; This work was supported by the National Science Foundation of China (NSFC-21875287), the Program for Guangdong Introducing Innovative and Entrepreneurial Teams (2017ZT07C069), and an NSF-DMR-1507252 grant (U.S.). Use of the NSLS, Brookhaven National Laboratory, was supported by the DOE BES (DE-AC02-98CH10886). M.R. is thankful for the Spanish Juan de la Cierva grant FPDI-2013-17582. Y.Z. and D.-X.Y. are supported by NKRDPC-2018YFA0306001, NKRDPC-2017YFA0206203, NSFC-11974432, NSFG-2019A1515011337, the National Supercomputer Center in Guangzhou, and the Leading Talent Program of Guangdong Special Projects. Work on IOP, CAS, was supported by NSFC and MOST grants. A portion of this research at ORNL's Spallation Neutron Source was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy. J.H. and M.H. thank the FWO for support for the electron microscopy studies through grant G035619N. We thank beamline BL14B1 (Shanghai Synchrotron Radiation Facility) for providing beam time and help during the experiments. ; |
Approved |
Most recent IF: 15; 2020 IF: 13.858 |
| Call Number |
UA @ admin @ c:irua:170294 |
Serial |
6646 |
| Permanent link to this record |
| |
|
| |
| Author |
Canossa, S.; Graiff, C.; Crocco, D.; Predieri, G. |
| Title |
Water structures and packing efficiency in methylene blue cyanometallate salts |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Crystals |
Abbreviated Journal |
Crystals |
| Volume |
10 |
Issue |
7 |
Pages |
558 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
Crystal structure prediction is the holy grail of crystal engineering and is key to its ambition of driving the formation of solids based on the selection of their molecular constituents. However, this noble quest is hampered by the limited predictability of the incorporation of solvent molecules, first and foremost the ubiquitous water. In this context, we herein report the structure of four methylene blue cyanometallate phases, where anions with various shapes and charges influence the packing motif and lead to the formation of differently hydrated structures. Importantly, water molecules are observed to play various roles as isolated fillings, dimers, or an infinite network with up to 13 water molecules per repeating unit. Each crystal structure has been determined by single-crystal X-ray diffraction and evaluated with the aid of Hirshfeld surface analysis, focussing on the role of water molecules and the hierarchy of different classes of interactions in the overall supramolecular landscape of the crystals. Finally, the collected pieces of evidence are matched together to highlight the leading role of MB stacking and to derive an explanation for the observed hydration diversity based on the structural role of water molecules in the crystal architecture. |
| 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 |
000554226900001 |
Publication Date |
2020-07-01 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
2073-4352 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
1.566 |
Times cited |
|
Open Access |
OpenAccess |
| Notes |
; The Elettra Synchrotron (CNR Trieste) is gratefully acknowledged for the beamtime allocated at the beamline XRD1 (proposal nr 20175216). S.C. acknowledges the Research Foundation Flanders (FWO) for supporting his research (grant nr. 12ZV120N). ; |
Approved |
Most recent IF: NA |
| Call Number |
UA @ admin @ c:irua:171279 |
Serial |
6653 |
| Permanent link to this record |
| |
|
| |
| Author |
Leemans, J.; Singh, S.; Li, C.; Ten Brinck, S.; Bals, S.; Infante, I.; Moreels, I.; Hens, Z. |
| Title |
Near-Edge Ligand Stripping and Robust Radiative Exciton Recombination in CdSe/CdS Core/Crown Nanoplatelets |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Journal Of Physical Chemistry Letters |
Abbreviated Journal |
J Phys Chem Lett |
| Volume |
11 |
Issue |
9 |
Pages |
3339-3344 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
We address the relation between surface chemistry and optoelectronic properties in semiconductor nanocrystals using core/crown CdSe/CdS nanoplatelets passivated by cadmium oleate (Cd(Ol)2) as model systems. We show that addition of butylamine to a nanoplatelet (NPL) dispersion maximally displaces ∼40% of the original Cd(Ol)2 capping. On the basis of density functional theory simulations, we argue that this behavior reflects the preferential displacement of Cd(Ol)2 from (near)-edge surface sites. Opposite from CdSe core NPLs, core/crown NPL dispersions can retain 45% of their initial photoluminescence efficiency after ligand displacement, while radiative exciton recombination keeps dominating the luminescent decay. Using electron microscopy observations, we assign this robust photoluminescence to NPLs with a complete CdS crown, which prevents charge carrier trapping in the near-edge surface sites created by ligand displacement. We conclude that Z-type ligands such as cadmium carboxylates can provide full electronic passivation of (100) facets yet are prone to displacement from (near)-edge surface sites. |
| 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 |
000535177500024 |
Publication Date |
2020-05-07 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
1948-7185 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
5.7 |
Times cited |
24 |
Open Access |
OpenAccess |
| Notes |
Universiteit Gent, GOA 01G01019 ; Fonds Wetenschappelijk Onderzoek, 17006602 FWO17/PDO/184 ; H2020 European Research Council, 714876 Phocona 815128 Realnano ; SIM-Flanders, SBO-QDOCCO ; Z.H. and S.B. acknowledge support by SIM-Flanders (SBO-QDOCCO). Z.H. acknowledges support by FWO-Vlaanderen (research project 17006602). Z.H. and I.M. acknowledge support by Ghent University (GOA n◦ 01G01019). J.L. acknowledges FWO-vlaanderen for a fellowship (SB PhD fellow at FWO). Sh.S acknowledges FWO postdoctoral funding (FWO17/PDO/184). This project has further received funding from the European Research Counsil under the European Union’s Horizon 2020 research and innovation programme (ERC Consolidator grant no. 815128 REALNANO and starting grant no. 714876 PHOCONA).; sygma |
Approved |
Most recent IF: 5.7; 2020 IF: 9.353 |
| Call Number |
EMAT @ emat @c:irua:173994 |
Serial |
6657 |
| Permanent link to this record |
| |
|
| |
| Author |
Imran, M.; Ramade, J.; Di Stasio, F.; De Franco, M.; Buha, J.; Van Aert, S.; Goldoni, L.; Lauciello, S.; Prato, M.; Infante, I.; Bals, S.; Manna, L. |
| Title |
Alloy CsCdxPb1–xBr3Perovskite Nanocrystals: The Role of Surface Passivation in Preserving Composition and Blue Emission |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Chemistry Of Materials |
Abbreviated Journal |
Chem Mater |
| Volume |
32 |
Issue |
|
Pages |
acs.chemmater.0c03825 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
Various strategies have been proposed to engineer the band gap of metal halide perovskite nanocrystals (NCs) while preserving their structure and composition and thus ensuring spectral stability of the emission color. An aspect that has only been marginally investigated is how the type of surface passivation influences the structural/color stability of AMX3 perovskite NCs composed of two different M2+ cations. Here, we report the synthesis of blue-emitting Cs-oleate capped CsCdxPb1–xBr3 NCs, which exhibit a cubic perovskite phase containing Cd-rich domains of Ruddlesden–Popper phases (RP phases). The RP domains spontaneously transform into pure orthorhombic perovskite ones upon NC aging, and the emission color of the NCs shifts from blue to green over days. On the other hand, postsynthesis ligand exchange with various Cs-carboxylate or ammonium bromide salts, right after NC synthesis, provides monocrystalline NCs with cubic phase, highlighting the metastability of RP domains. When NCs are treated with Cs-carboxylates (including Cs-oleate), most of the Cd2+ ions are expelled from NCs upon aging, and the NCs phase evolves from cubic to orthorhombic and their emission color changes from blue to green. Instead, when NCs are coated with ammonium bromides, the loss of Cd2+ ions is suppressed and the NCs tend to retain their blue emission (both in colloidal dispersions and in electroluminescent devices), as well as their cubic phase, over time. The improved compositional and structural stability in the latter cases is ascribed to the saturation of surface vacancies, which may act as channels for the expulsion of Cd2+ ions from NCs. |
| 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 |
000603288800034 |
Publication Date |
2020-12-04 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
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| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0897-4756 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
8.6 |
Times cited |
44 |
Open Access |
OpenAccess |
| Notes |
European Commission; Fonds Wetenschappelijk Onderzoek, G.0267.18N ; H2020 European Research Council, 770887 815128 851794 ; We acknowledge funding from the FLAG-ERA JTC2019 project PeroGas. S.B., and S.V.A. acknowledges funding from the European Research Council under the European Union’s Horizon 2020 research and innovation program (ERC Consolidator Grants #815128REALNANO and #770887PICOMETRICS) and from the Research Foundation Flanders (FWO, Belgium) through project funding G.0267.18N. F.D.S. acknowledges the funding from ERC starting grant NANOLED (851794). The computational work was carried out on the Dutch National e-infrastructure with the support of the SURF Cooperative; sygma |
Approved |
Most recent IF: 8.6; 2020 IF: 9.466 |
| Call Number |
EMAT @ emat @c:irua:174004 |
Serial |
6659 |
| Permanent link to this record |
| |
|
| |
| Author |
Savchenko, T.M.; Buzzi, M.; Howald, L.; Ruta, S.; Vijayakumar, J.; Timm, M.; Bracher, D.; Saha, S.; Derlet, P.M.; Béché, A.; Verbeeck, J.; Chantrell, R.W.; Vaz, C.A.F.; Nolting, F.; Kleibert, A. |
| Title |
Single femtosecond laser pulse excitation of individual cobalt nanoparticles |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Physical Review B |
Abbreviated Journal |
Phys Rev B |
| Volume |
102 |
Issue |
20 |
Pages |
205418 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
Laser-induced manipulation of magnetism at the nanoscale is a rapidly growing research topic with potential for applications in spintronics. In this work, we address the role of the scattering cross section, thermal effects, and laser fluence on the magnetic, structural, and chemical stability of individual magnetic nanoparticles excited by single femtosecond laser pulses. We find that the energy transfer from the fs laser pulse to the nanoparticles is limited by the Rayleigh scattering cross section, which in combination with the light absorption of the supporting substrate and protective layers determines the increase in the nanoparticle temperature. We investigate individual Co nanoparticles (8 to 20 nm in size) as a prototypical model system, using x-ray photoemission electron microscopy and scanning electron microscopy upon excitation with single femtosecond laser pulses of varying intensity and polarization. In agreement with calculations, we find no deterministic or stochastic reversal of the magnetization in the nanoparticles up to intensities where ultrafast demagnetization or all-optical switching is typically reported in thin films. Instead, at higher fluences, the laser pulse excitation leads to photo-chemical reactions of the nanoparticles with the protective layer, which results in an irreversible change in the magnetic properties. Based on our findings, we discuss the conditions required for achieving laser-induced switching in isolated nanomagnets. |
| 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 |
000589602000005 |
Publication Date |
2020-11-16 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
2469-9950 |
ISBN |
|
Additional Links |
UA library record; WoS full record |
| Impact Factor |
3.7 |
Times cited |
1 |
Open Access |
OpenAccess |
| Notes |
This work received funding by the Swiss National Foundation (SNF) (Grants No. 200021160186 and No. 2002153540), the Swiss Nanoscience Institute (SNI) (Grant No. SNI P1502), the European Union’s Horizon 2020 research and innovation programme under Grant Agreement No. 737093 (FEMTOTERABYTE), and the COST Action CA17123 (MAGNETOFON). Part of this work was performed at the SIM beamline of the Swiss Light Source (SLS), Paul Scherrer Institut, Villigen, Switzerland. Part of the simulations were undertaken on the VIKING cluster, which is a high-performance compute facility provided by the University of York. We kindly acknowledge Anja Weber from PSI for preparation of substrates with marker structures. A.B. and Jo Verbeeck acknowledge funding through FWO Project No. G093417N (“Compressed sensing enabling low dose imaging in transmission electron microscopy”) from the Flanders Research Fund. Jo Verbeeck acknowledges funding from the European Union’s Horizon 2020 research and innovation program under Grant Agreement No. 823717 – ESTEEM3. S.S. acknowledges ETH Zurich Post-Doctoral fellowship and Marie Curie actions for people COFUND program.; esteem3JRA; esteem3reported |
Approved |
Most recent IF: 3.7; 2020 IF: 3.836 |
| Call Number |
EMAT @ emat @c:irua:174273 |
Serial |
6669 |
| Permanent link to this record |
| |
|
| |
| Author |
Xu, X.; Jones, M.A.; Cassidy, S.J.; Manuel, P.; Orlandi, F.; Batuk, M.; Hadermann, J.; Clarke, S.J. |
| Title |
Magnetic Ordering in the Layered Cr(II) Oxide Arsenides Sr2CrO2Cr2As2and Ba2CrO2Cr2As2 |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Inorganic Chemistry |
Abbreviated Journal |
Inorg Chem |
| Volume |
59 |
Issue |
21 |
Pages |
15898-15912 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
Sr2CrO2Cr2As2 and Ba2CrO2Cr2As2 with Cr2+ ions in CrO2 sheets and in CrAs layers crystallize with the Sr2Mn3Sb2O2 structure (space group I4/mmm, Z = 2) and lattice parameters a = 4.00800(2) Å, c = 18.8214(1) Å (Sr2CrO2Cr2As2) and a = 4.05506(2) Å, c = 20.5637(1) Å (Ba2CrO2Cr2As2) at room temperature. Powder neutron diffraction reveals checkerboard-type antiferromagnetic ordering of the Cr2+ ions in the arsenide layers below TN1Sr, of 600(10) K (Sr2CrO2Cr2As2) and TN1Ba 465(5) K (Ba2CrO2Cr2As2) with the moments initially directed perpendicular to the layers in both compounds. Checkerboard-type antiferromagnetic ordering of the Cr2+ ions in the oxide layer below 230(5) K for Ba2CrO2Cr2As2 occurs with these moments also perpendicular to the layers, consistent with the orientation preferences of d4 moments in the two layers. In contrast, below 330(5) K in Sr2CrO2Cr2As2, the oxide layer Cr2+ moments are initially oriented in the CrO2 plane; but on further cooling, these moments rotate to become perpendicular to the CrO2 planes, while the moments in the arsenide layers rotate by 90° with the moments on the two sublattices remaining orthogonal throughout [behavior recently reported independently by Liu et al. [Liu et al. Phys. Rev. B 2018, 98, 134416]]. In Sr2CrO2Cr2As2, electron diffraction and high resolution powder X-ray diffraction data show no evidence for a structural distortion that would allow the two Cr2+ sublattices to couple, but high resolution neutron powder diffraction data suggest a small incommensurability between the magnetic structure and the crystal structure, which may account for the coupling of the two sublattices and the observed spin reorientation. The saturation values of the Cr2+ moments in the CrO2 layers (3.34(1) μB (for Sr2CrO2Cr2As2) and 3.30(1) μB (for Ba2CrO2Cr2As2)) are larger than those in the CrAs layers (2.68(1) μB for Sr2CrO2Cr2As2 and 2.298(8) μB for Ba2CrO2Cr2As2) reflecting greater covalency in the arsenide layers. |
| 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 |
000588738100035 |
Publication Date |
2020-11-02 |
| Series Editor |
|
Series Title |
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Abbreviated Series Title |
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| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0020-1669 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
4.6 |
Times cited |
|
Open Access |
OpenAccess |
| Notes |
We thank the UK EPSRC (EP/M020517/1 and EP/P018874/ 1) and the Leverhulme Trust (RPG-2014-221) for funding and the ISIS pulsed neutron and muon source (RB1610357 and RB1700075) and the Diamond Light Source Ltd. (EE13284 and EE18786) for the award of beam time. We thank Dr. A. Baker and Dr. C. Murray for support on I11. |
Approved |
Most recent IF: 4.6; 2020 IF: 4.857 |
| Call Number |
EMAT @ emat @c:irua:176058 |
Serial |
6704 |
| Permanent link to this record |
| |
|
| |
| Author |
Kamminga, M.E.; Batuk, M.; Hadermann, J.; Clarke, S.J. |
| Title |
Misfit phase (BiSe)1.10NbSe2 as the origin of superconductivity in niobium-doped bismuth selenide |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Communications Materials |
Abbreviated Journal |
Commun Mater |
| Volume |
1 |
Issue |
1 |
Pages |
82 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
Topological superconductivity is of great contemporary interest and has been proposed in doped Bi<sub>2</sub>Se<sub>3</sub>, in which electron-donating atoms such as Cu, Sr or Nb have been intercalated into the Bi<sub>2</sub>Se<sub>3</sub>structure. For Nb<sub><italic>x</italic></sub>Bi<sub>2</sub>Se<sub>3</sub>, with<italic>T</italic><sub>c</sub> ~ 3 K, it is assumed in the literature that Nb is inserted in the van der Waals gap. However, in this work an alternative origin for the superconductivity in Nb-doped Bi<sub>2</sub>Se<sub>3</sub>is established. In contrast to previous reports, it is deduced that Nb intercalation in Bi<sub>2</sub>Se<sub>3</sub>does not take place. Instead, the superconducting behaviour in samples of nominal composition Nb<sub><italic>x</italic></sub>Bi<sub>2</sub>Se<sub>3</sub>results from the (BiSe)<sub>1.10</sub>NbSe<sub>2</sub>misfit phase that is present in the sample as an impurity phase for small<italic>x</italic>(0.01 ≤ <italic>x</italic> ≤ 0.10) and as a main phase for large<italic>x</italic>(<italic>x</italic> = 0.50). The structure of this misfit phase is studied in detail using a combination of X-ray diffraction and transmission electron microscopy techniques. |
| Address |
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| Corporate Author |
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Thesis |
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Place of Publication |
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Editor |
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Wos |
000610580800001 |
Publication Date |
2020-11-10 |
| 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 |
|
Edition |
|
| ISSN |
2662-4443 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
|
Times cited |
|
Open Access |
OpenAccess |
| Notes |
M.E.K. was supported by the Netherlands Organisation for Scientific Research (NWO, grant code 019.181EN.003). We also acknowledge support from the EPSRC (EP/ R042594/1, EP/P018874/1, EP/M020517/1) and the Leverhulme Trust (RPG-2018-377). J.H. acknowledges support from the University of Antwerp through BOF Grant No. 31445. We thank DLS Ltd for beam time (EE18786), Dr Clare Murray for assistance on I11 and Dr Jon Wade from the Department of Earth Sciences, University of Oxford for performing the SEM measurements. We also thank Dr Michal Dušak and Dr Václav Petřiček for their advice concerning the use of the Jana2006 software. |
Approved |
Most recent IF: NA |
| Call Number |
EMAT @ emat @c:irua:176116 |
Serial |
6705 |
| Permanent link to this record |
| |
|
| |
| Author |
Lin, S.-C.; Kuo, C.-T.; Shao, Y.-C.; Chuang, Y.-D.; Geessinck, J.; Huijben, M.; Rueff, J.-P.; Graff, I.L.; Conti, G.; Peng, Y.; Bostwick, A.; Gullikson, E.; Nemsak, S.; Vailionis, A.; Gauquelin, N.; Verbeeck, J.; Ghiringhelli, G.; Schneider, C.M.; Fadley, C.S. |
| Title |
Two-dimensional electron systems in perovskite oxide heterostructures : role of the polarity-induced substitutional defects |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Physical review materials |
Abbreviated Journal |
|
| Volume |
4 |
Issue |
11 |
Pages |
115002 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
The discovery of a two-dimensional electron system (2DES) at the interfaces of perovskite oxides such as LaAlO3 and SrTiO3 has motivated enormous efforts in engineering interfacial functionalities with this type of oxide heterostructures. However, the fundamental origins of the 2DES are still not understood, e.g., the microscopic mechanisms of coexisting interface conductivity and magnetism. Here we report a comprehensive spectroscopic investigation on the depth profile of 2DES-relevant Ti 3d interface carriers using depthand element-specific techniques like standing-wave excited photoemission and resonant inelastic scattering. We found that one type of Ti 3d interface carriers, which give rise to the 2DES are located within three unit cells from the n-type interface in the SrTiO3 layer. Unexpectedly, another type of interface carriers, which are polarity-induced Ti-on-Al antisite defects, reside in the first three unit cells of the opposing LaAlO3 layer (similar to 10 angstrom). Our findings provide a microscopic picture of how the localized and mobile Ti 3d interface carriers distribute across the interface and suggest that the 2DES and 2D magnetism at the LaAlO3/SrTiO3 interface have disparate explanations as originating from different types of interface carriers. |
| Address |
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Thesis |
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Place of Publication |
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Editor |
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| Language |
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Wos |
000592432200004 |
Publication Date |
2020-11-20 |
| 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 |
2475-9953 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
3.4 |
Times cited |
7 |
Open Access |
OpenAccess |
| Notes |
; We thank G. M. De Luca and L. Braicovich for discussions. Charles S. Fadley was deceased on August 1, 2019. We are grateful for his significant contributions to this work. We thank Advanced Light Source for the access to Beamline 8.0.3 (qRIXS) via Proposal No. 09892 and beamline 7.0.2 (MAESTRO) via Proposal No. RA-00291 that contributed to the results presented here. We thank synchrotron SOLEIL (via Proposal No. 99180118) for the access to Beamline GALAXIES. This work was supported by the U.S. Department of Energy (DOE) under Contract No. DE-AC02-05CH11231 (Advanced Light Source), and by DOE Contract No. DE-SC0014697 through the University of California, Davis (S.-C.L., C.-T.K, and C.S.F.), and from the Julich Research Center, Peter Grunberg Institute, PGI-6. I. L. G. wishes to thank Brazilian scientific agencies CNPQ (Project No. 200789/2017-1) and CAPES (CAPES-PrInt-UFPR) for their financial support. J.V. and N.G. acknowledge funding from the Geconcentreerde Onderzoekacties (GOA) project “Solarpaint” of the University of Antwerp and the European Union's horizon 2020 research and innovation program ES-TEEM3 under grant agreement no 823717. The Qu-Ant-EM microscope used in this study was partly funded by the Hercules fund from the Flemish Government. ; esteem3TA; esteem3reported |
Approved |
Most recent IF: 3.4; 2020 IF: NA |
| Call Number |
UA @ admin @ c:irua:174316 |
Serial |
6713 |
| Permanent link to this record |
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| |
| Author |
Skaggs, C.M.; Kang, C.-J.; Perez, C.J.; Hadermann, J.; Emge, T.J.; Frank, C.E.; Pak, C.; Lapidus, S.H.; Walker, D.; Kotliar, G.; Kauzlarich, S.M.; Tan, X.; Greenblatt, M. |
| Title |
Ambient and high pressure CuNiSb₂ : metal-ordered and metal-disordered NiAs-type derivative pnictides |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Inorganic Chemistry |
Abbreviated Journal |
Inorg Chem |
| Volume |
59 |
Issue |
19 |
Pages |
14058-14069 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
The mineral Zlatogorite, CuNiSb2, was synthesized in the laboratory for the first time by annealing elements at ambient pressure (CuNiSb2-AP). Rietveld refinement of synchrotron powder X-ray diffraction data indicates that CuNiSb2-AP crystallizes in the NiAs-derived structure (P (3) over bar m1, #164) with Cu and Ni ordering. The structure consists of alternate NiSb6 and CuSb6 octahedral layers via face-sharing. The formation of such structure instead of metal disordered NiAs-type structure (P6(3)/mmc, #194) is validated by the lower energy of the ordered phase by first-principle calculations. Interatomic crystal orbital Hamilton population, electron localization function, and charge density analysis reveal strong Ni-Sb, Cu-Sb, and Cu-Ni bonding and long weak Sb-Sb interactions in CuNiSb2-AP. The magnetic measurement indicates that CuNiSb2-AP is Pauli paramagnetic. First-principle calculations and experimental electrical resistivity measurements reveal that CuNiSb2-AP is a metal. The low Seebeck coefficient and large thermal conductivity suggest that CuNiSb2 is not a potential thermoelectric material. Single crystals were grown by chemical vapor transport. The high pressure sample (CuNiSb2-8 GPa) was prepared by pressing CuNiSb2-AP at 700 degrees C and 8 GPa. However, the structures of single crystal and CuNiSb2-8 GPa are best fit with a disordered metal structure in the P (3) over bar m1 space group, corroborated by transmission electron microscopy. |
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| Language |
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Wos |
000580381700028 |
Publication Date |
2020-09-20 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0020-1669 |
ISBN |
|
Additional Links |
UA library record; WoS full record |
| Impact Factor |
4.6 |
Times cited |
|
Open Access |
OpenAccess |
| Notes |
|
Approved |
Most recent IF: 4.6; 2020 IF: 4.857 |
| Call Number |
UA @ admin @ c:irua:174331 |
Serial |
6714 |
| Permanent link to this record |
| |
|
| |
| Author |
Sun, M.-H.; Zhou, J.; Hu, Z.-Y.; Chen, L.-H.; Li, L.-Y.; Wang, Y.-D.; Xie, Z.-K.; Turner, S.; Van Tendeloo, G.; Hasan, T.; Su, B.-L. |
| Title |
Hierarchical zeolite single-crystal reactor for excellent catalytic efficiency |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Matter |
Abbreviated Journal |
|
| Volume |
3 |
Issue |
4 |
Pages |
1226-1245 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
As a size- and shape-selective catalyst, zeolites are widely used in petroleum and fine-chemicals processing. However, their small micropores severely hinder molecular diffusion and are sensitive to coke formation. Hierarchically porous zeolite single crystals with fully interconnected, ordered, and tunable multimodal porosity at macro-, meso-, and microlength scale, like in leaves, offer the ideal solution. However, their synthesis remains highly challenging. Here, we report a versatile confined zeolite crystallization process to achieve these superior properties. Such zeolite single crystals lead to significantly improved mass transport properties by shortening the diffusion length while maintaining shape-selective properties, endowing them with a high efficiency of zeolite crystals, enhanced catalytic activities and lifetime, highly reduced coke formation, and reduced deactivation rate in bulky-molecule reactions and methanol-to-olefins process. Their industrial utilization can lead to the design of innovative and intensified reactors and processes with highly enhanced efficiency and minimum energy consumption. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000581132600021 |
Publication Date |
2020-08-12 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
|
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
|
Times cited |
|
Open Access |
OpenAccess |
| Notes |
|
Approved |
Most recent IF: NA |
| Call Number |
UA @ admin @ c:irua:174329 |
Serial |
6727 |
| Permanent link to this record |
| |
|
| |
| Author |
Mahadi, A.H.; Ye, L.; Fairclough, S.M.; Qu, J.; Wu, S.; Chen, W.; Papaioannou, E.; Ray, B.; Pennycook, T.J.; Haigh, S.J.; Young, N.P.; Tedsree, K.; Metcalfe, I.S.; Tsang, S.C.E. |
| Title |
Beyond surface redox and oxygen mobility at pd-polar ceria (100) interface : underlying principle for strong metal-support interactions in green catalysis |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Applied Catalysis B-Environmental |
Abbreviated Journal |
Appl Catal B-Environ |
| Volume |
270 |
Issue |
|
Pages |
118843 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
When ceria is used as a support for many redox catalysis involved in green catalysis, it is well-known that the overlying noble metal can gain access to a significant quantity of oxygen atoms with high mobility and fast reduction and oxidation properties under mild conditions. However, it is as yet unclear what the underlying principle and the nature of the ceria surface involved are. By using two tailored morphologies of ceria nanocrystals, namely cubes and rods, it is demonstrated from Scanning Transmission Electron Microscopy with Electron Energy Loss Spectroscopy (STEM-EELS) mapping and Pulse Isotopic Exchange (PIE) that ceria nano-cubes terminated with a polar surface (100) can give access to more than the top most layer of surface oxygen atoms. Also, they give higher oxygen mobility than ceria nanorods with a non-polar facet of (110). A new insight for the possible additional role of polar ceria surface plays in the oxygen mobility is obtained from Density Functional Theory (DFT) calculations which suggest that the (100) surface sites that has more than half-filled O on same plane can drive oxygen atoms to oxidise adsorbate(s) on Pd due to the strong electrostatic repulsion. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000526110500007 |
Publication Date |
2020-03-04 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0926-3373 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
22.1 |
Times cited |
|
Open Access |
|
| Notes |
|
Approved |
Most recent IF: 22.1; 2020 IF: 9.446 |
| Call Number |
UA @ admin @ c:irua:183959 |
Serial |
6856 |
| Permanent link to this record |
| |
|
| |
| Author |
Zewdie, M.C.; Van Passel, S.; Moretti, M.; Annys, S.; Tenessa, D.B.; Ayele, Z.A.; Tsegaye, E.A.; Cools, J.; Minale, A.S.; Nyssen, J. |
| Title |
Pathways how irrigation water affects crop revenue of smallholder farmers in northwest Ethiopia: A mixed approach |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Agricultural Water Management |
Abbreviated Journal |
Agr Water Manage |
| Volume |
233 |
Issue |
|
Pages |
106101 |
| Keywords |
A1 Journal article; Economics; Engineering sciences. Technology; Engineering Management (ENM); Sustainable Energy, Air and Water Technology (DuEL) |
| Abstract |
The relationship between irrigation water availability and crop revenue is multifaceted. However, most of the previous studies focused only on the direct effect of irrigation water on crop revenue or considered that the indirect effect passes only through the farmers’ improved farm inputs usage. Nevertheless, unlike previous studies, this study argues that a one-sided argument that irrigation water directly causes high crop revenue or indirectly affects crop revenue only via the farmers’ improved farm inputs usage is incomplete, as irrigation water not only directly contributes to crop revenue but also indirectly conduces to crop revenue via both the type of crops produced and the farmers’ improved farm inputs usage. Considering the previous studies’ limitations, this study investigates pathways how small-scale irrigation water affects crop revenue and identifies challenges of small-scale irrigation farming in Fogera district, Ethiopia. Results endorsed that irrigation water has both direct and indirect effects on crop revenue. The indirect effect is 67 percent of the total effect and it is mediated by both the type of crops produced and farmers’ improved farm inputs usage. The result also indicated that irrigation user farmers have a higher income, more livestock assets and resources and better food, housing, and cloths than the non-users. Moreover, challenges related to agricultural output and input market were identified as the most severe problem followed by crop disease. The findings of our study suggest that to utilize the benefits of irrigation water properly, it is crucial to encourage farmers to use more improved farm inputs and to shift from staple to cash crop production. Moreover, farmers are frequently exposed to cheating by illegal brokers in the output market, therefore it is also important to increase farmers’ accessibility to output and input markets, the quality of improved farm inputs, and the bargaining power of farmers with market information. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000525291200025 |
Publication Date |
2020-02-29 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0378-3774 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
6.7 |
Times cited |
|
Open Access |
|
| Notes |
Bahir Dar University – Institutional University Cooperation; |
Approved |
Most recent IF: 6.7; 2020 IF: 2.848 |
| Call Number |
ENM @ enm @c:irua:167592 |
Serial |
6353 |
| Permanent link to this record |
| |
|
| |
| Author |
Peeters, M.; Compernolle, T.; Van Passel, S. |
| Title |
Simulation of a controlled water heating system with demand response remunerated on imbalance market pricing |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Journal of building engineering |
Abbreviated Journal |
|
| Volume |
27 |
Issue |
27 |
Pages |
100969 |
| Keywords |
A1 Journal article; Economics; Engineering sciences. Technology; Economics; Engineering Management (ENM) |
| Abstract |
Buildings are responsible for 40% of our worldwide energy consumption and 50% of this energy is converted for Heating Ventilation Air Conditioning (HVAC) systems in buildings. The increasing share of renewable energy production required to make the transition towards a carbon neutral energy system challenges the stability of the grid. Through demand response it becomes possible to activate these systems in support of grid balancing. However, this flexibility is currently not rewarded in the market. We simulate a domestic water heater participating in the balancing of the electricity net and calculated the revenue from this action. We simulate a water heater in connection with an Economic Model Predictive Controller (EMPC) which takes future usage, energy cost, and reward for delivering balanced power into account. We show that the choice of an EMPC controller is valid as it allows the setpoint to change if certain conditions are met, leading to a more optimal revenue stream from selling flexibility. We find that the economic benefits of participating in delivering balancing power is considerable and offset an increase in energy costs. The increase in energy consumption could be justified as the participation in net stabilisation allows the macro-system to integrate more renewable energy sources. More importantly, the simulations also show that the poorer the energy performance of the water heater, the more flexibility can be sold. From a policy point of view, a minimal energy performance should be determined before allowing participation in net stabilisation. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000502361000075 |
Publication Date |
2019-09-27 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
|
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
|
Times cited |
|
Open Access |
|
| Notes |
; Tine Compernolle thanks the Research Foundation Flanders (FWO) for funding her postdoctoral mandate [grant number 12M7417N]. ; |
Approved |
Most recent IF: NA |
| Call Number |
UA @ admin @ c:irua:164236 |
Serial |
6248 |
| Permanent link to this record |
| |
|
| |
| Author |
Peeters, M.; Compernolle, T.; Van Passel, S. |
| Title |
Influence of information provided at the moment of a fire alarm on the choice of exit |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Fire Safety Journal |
Abbreviated Journal |
Fire Safety J |
| Volume |
117 |
Issue |
|
Pages |
103221-103228 |
| Keywords |
A1 Journal article; Economics; Engineering Management (ENM); Center for Oncological Research (CORE) |
| Abstract |
The data generated in buildings are used for all types of purposes. The quality of information used in assisting people to escape an emergency situation is of importance. In practice today, none of the data-generating systems that aid in the escape from emergency situations is validated on a regular basis. This study is based on the smart building concept. The rationale behind this concept is to provide information about a building and the usage of that building at each moment in time. An experiment was conducted to measure the impact of different types of information on participants' choice of exit, exit time and distance travelled. Seven identical floors of one building were used with different setups to see if the choice of exit is influenced by the type of information provided at the moment of an alarm. It was found that the information does have a significant impact on the choice of exit, escape speed and distance travelled. Furthermore, it was shown that false information can increase the time it takes to leave the building and the distance travelled, impacting the survival rate. The more imperative information is visualised, the stronger its influence is on the choices made. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000579650800011 |
Publication Date |
2020-09-15 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0379-7112 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
3.1 |
Times cited |
|
Open Access |
|
| Notes |
|
Approved |
Most recent IF: 3.1; 2020 IF: 1.165 |
| Call Number |
UA @ admin @ c:irua:175125 |
Serial |
6929 |
| Permanent link to this record |
| |
|
| |
| Author |
Sharafi, L.; Zarafshani, K.; Keshavarz, M.; Azadi, H.; Van Passel, S. |
| Title |
Drought risk assessment: Towards drought early warning system and sustainable environment in western Iran |
Type |
A1 Journal Article |
| Year |
2020 |
Publication |
Ecological Indicators |
Abbreviated Journal |
Ecological Indicators |
| Volume |
114 |
Issue |
|
Pages |
106276 |
| Keywords |
A1 Journal Article; Drought; Early warning system; Risk management; Vulnerability; Environmental risk; Resilient farming; Engineering Management (ENM) ; |
| Abstract |
Prolonged drought is considered as a creeping natural hazard, which has created a financial burden and unsustainable environment in Iran. Moreover, the effect of drought phenomenon in rural areas is more extensive, causing significant challenges to the rural economy in general and agricultural production in particular. A common strategy to manage drought is based on crisis management (ex-ante). However, for effective drought management, risk management seems to be more in line with drought early warning systems. This quantitative study used risk assessment, which is the function of two elements such as hazard (SPI and SDI indices) and vulnerability (exposure, sensitivity, and adaptive capacity). This study aims to build the foundations for drought early warning systems in limited resource areas such as Kermanshah Township in the northwestern part of Iran. The population of this study comprised of wheat farmers in which 293 farmers were selected using multistage cluster sampling method. In the next step, the drought risk map for Kermanshah Township was developed, which revealed that the majority of villages are at intense environmental risk. The result of this study has implications for drought management practitioners. For example, the results can aid policymakers in the design of an early warning system in order to reduce risk and thus empower farmers toward resilient farming. |
| Address |
|
| Corporate Author |
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Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000559966500006 |
Publication Date |
2020-04-09 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
1470160X |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
|
Times cited |
|
Open Access |
|
| Notes |
|
Approved |
Most recent IF: NA |
| Call Number |
ENM @ enm @c:irua:170071 |
Serial |
6380 |
| Permanent link to this record |
| |
|
| |
| Author |
Jalali, H.; Ghorbanfekr, H.; Hamid, I.; Neek-Amal, M.; Rashidi, R.; Peeters, F.M. |
| Title |
Out-of-plane permittivity of confined water |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Physical Review E |
Abbreviated Journal |
Phys Rev E |
| Volume |
102 |
Issue |
2 |
Pages |
022803 |
| Keywords |
A1 Journal article; Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
| Abstract |
The dielectric properties of confined water is of fundamental interest and is still controversial. For water confined in channels with height smaller than h = 8 angstrom, we found a commensurability effect and an extraordinary decrease in the out-of-plane dielectric constant down to the limit of the dielectric constant of optical water. Spatial resolved polarization density data obtained from molecular dynamics simulations are found to be antisymmetric across the channel and are used as input in a mean-field model for the dielectric constant as a function of the height of the channel for h > 15 angstrom. Our results are in excellent agreement with a recent experiment [L. Fumagalli et al., Science 360, 1339 (2018)]. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000560660400004 |
Publication Date |
2020-08-11 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
1539-3755; 1550-2376 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.366 |
Times cited |
38 |
Open Access |
|
| Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Methusalem program. ; |
Approved |
Most recent IF: NA |
| Call Number |
UA @ admin @ c:irua:171157 |
Serial |
6574 |
| Permanent link to this record |
| |
|
| |
| Author |
Bafekry, A.; Stampfl, C.; Shayesteh, S.F. |
| Title |
A first-principles study of C3N nanostructures : control and engineering of the electronic and magnetic properties of nanosheets, tubes and ribbons |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Chemphyschem |
Abbreviated Journal |
Chemphyschem |
| Volume |
21 |
Issue |
2 |
Pages |
164-174 |
| Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
| Abstract |
Using first-principles calculations we systematically investigate the atomic, electronic and magnetic properties of novel two-dimensional materials (2DM) with a stoichiometry C3N which has recently been synthesized. We investigate how the number of layers affect the electronic properties by considering monolayer, bilayer and trilayer structures, with different stacking of the layers. We find that a transition from semiconducting to metallic character occurs which could offer potential applications in future nanoelectronic devices. We also study the affect of width of C3N nanoribbons, as well as the radius and length of C3N nanotubes, on the atomic, electronic and magnetic properties. Our results show that these properties can be modified depending on these dimensions, and depend markedly on the nature of the edge states. Functionalization of the nanostructures by the adsorption of H adatoms is found induce metallic, half-metallic, semiconducting and ferromagnetic behavior, which offers an approach to tailor the properties, as can the application of strain. Our calculations give insight into this new family of C3N nanostructures, which reveal unusual electronic and magnetic properties, and may have great potential in applications such as sensors, electronics and optoelectronic at the nanoscale. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000503453100001 |
Publication Date |
2019-11-09 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
1439-4235 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.9 |
Times cited |
27 |
Open Access |
|
| Notes |
; ; |
Approved |
Most recent IF: 2.9; 2020 IF: 3.075 |
| Call Number |
UA @ admin @ c:irua:165045 |
Serial |
6282 |
| Permanent link to this record |
| |
|
| |
| Author |
Bafekry, A.; Stampfl, C.; Ghergherehchi, M.; Shayesteh, S.F. |
| Title |
A first-principles study of the effects of atom impurities, defects, strain, electric field and layer thickness on the electronic and magnetic properties of the C2N nanosheet |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Carbon |
Abbreviated Journal |
Carbon |
| Volume |
157 |
Issue |
157 |
Pages |
371-384 |
| Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
| Abstract |
Using the first-principles calculations, we explore the structural and novel electronic/optical properties of the C2N nanosheet. To this goal, we systematically investigate the affect of layer thickness, electrical field and strain on the electronic properties of the C2N nanosheet. By increasing the thickness of C2N, we observed that the band gap decreases. Moreover, by applying an electrical field to bilayer C2N, the band gap decreases and a semiconductor-to-metal transition can occur. Our results also confirm that uniaxial and biaxial strain can effectively alter the band gap of C2N monolayer. Furthermore, we show that the electronic and magnetic properties of C2N can be modified by the adsorption and substitution of various atoms. Depending on the species of embedded atoms, they may induce semiconductor (O, C, Si and Be), metal (S, N, P, Na, K, Mg and Ca), dilute-magnetic semiconductor (H, F, B), or ferro-magnetic-metal (Cl, Li) character in C2N monolayer. It was also found that the inclusion of hydrogen or oxygen impurities and nitrogen vacancies, can induce magnetism in the C2N monolayer. These extensive calculations can be useful to guide future studies to modify the electronic/optical properties of two-dimensional materials. (C) 2019 Elsevier Ltd. All rights reserved. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000502548500044 |
Publication Date |
2019-10-22 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0008-6223 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
10.9 |
Times cited |
49 |
Open Access |
|
| Notes |
; This work was supported by the National Research Foundation of Korea grant funded by the Korea government (MSIT) (NRF-2017R1A2B2011989). We are thankful for comments by Meysam Baghery Tagani from department of physics in University of Guilan and Bohayra Mortazavi from Gottfried Wilhelm Leibniz Universitat Hannover, Hannover, Germany. ; |
Approved |
Most recent IF: 10.9; 2020 IF: 6.337 |
| Call Number |
UA @ admin @ c:irua:165024 |
Serial |
6283 |
| Permanent link to this record |
| |
|
| |
| 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 |
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Thesis |
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| 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 |
| Permanent link to this record |
| |
|
| |
| Author |
Gonzalez-Garcia, A.; Lopez-Perez, W.; Gonzalez-Hernandez, R.; Rivera-Julio, J.; Espejo, C.; Milošević, M.V.; Peeters, F.M. |
| Title |
Two-dimensional hydrogenated buckled gallium arsenide: an ab initio study |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Journal Of Physics-Condensed Matter |
Abbreviated Journal |
J Phys-Condens Mat |
| Volume |
32 |
Issue |
14 |
Pages |
145502 |
| Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
| Abstract |
First-principles calculations have been carried out to investigate the stability, structural and electronic properties of two-dimensional (2D) hydrogenated GaAs with three possible geometries: chair, zigzag-line and boat configurations. The effect of van der Waals interactions on 2D H-GaAs systems has also been studied. These configurations were found to be energetic and dynamic stable, as well as having a semiconducting character. Although 2D GaAs adsorbed with H tends to form a zigzag-line configuration, the energy differences between chair, zigzag-line and boat are very small which implies the metastability of the system. Chair and boat configurations display a – direct bandgap nature, while pristine 2D-GaAs and zigzag-line are indirect semiconductors. The bandgap sizes of all configurations are also hydrogen dependent, and wider than that of pristine 2D-GaAs with both PBE and HSE functionals. Even though DFT-vdW interactions increase the adsorption energies and reduce the equilibrium distances of H-GaAs systems, it presents, qualitatively, the same physical results on the stability and electronic properties of our studied systems with PBE functional. According to our results, 2D buckled gallium arsenide is a good candidate to be synthesized by hydrogen surface passivation as its group III-V partners 2D buckled gallium nitride and boron nitride. The hydrogenation of 2D-GaAs tunes the bandgap of pristine 2D-GaAs, which makes it a potential candidate for optoelectronic applications in the blue and violet ranges of the visible electromagnetic spectrum. |
| Address |
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Thesis |
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Place of Publication |
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Editor |
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| Language |
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Wos |
000507894400001 |
Publication Date |
2019-12-11 |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0953-8984 |
ISBN |
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Additional Links |
UA library record; WoS full record |
| Impact Factor |
2.7 |
Times cited |
2 |
Open Access |
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| Notes |
; This work has been carried out by the financial support of Universidad del Norte and Colciencias (Administrative Department of Science, Technology and Research of Colombia) under Convocatoria 712-Convocatoria para proyectos de investigacion en Ciencias Basicas, ano 2015, Cod: 121571250192, Contrato 110-216. The authors gratefully acknowledge the support from the High Performance Computing core facility CalcUA and the TOPBOF project at the University of Antwerp, Belgium; and the computing time granted on the supercomputer Mogon at Johannes Gutenberg University Mainz (hpc.uni-mainz.de). ; |
Approved |
Most recent IF: 2.7; 2020 IF: 2.649 |
| Call Number |
UA @ admin @ c:irua:165644 |
Serial |
6330 |
| Permanent link to this record |
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| Author |
Vanherck, J.; Bacaksiz, C.; Sorée, B.; Milošević, M.V.; Magnus, W. |
| Title |
2D ferromagnetism at finite temperatures under quantum scrutiny |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Applied Physics Letters |
Abbreviated Journal |
Appl Phys Lett |
| Volume |
117 |
Issue |
5 |
Pages |
052401 |
| Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
| Abstract |
Recent years have seen a tremendous rise of two-dimensional (2D) magnetic materials, several of which were verified experimentally. However, most of the theoretical predictions to date rely on ab initio methods, at zero temperature and fluctuation-free, while one certainly expects detrimental quantum fluctuations at finite temperatures. Here, we present the solution of the quantum Heisenberg model for honeycomb/hexagonal lattices with anisotropic exchange interaction up to third nearest neighbors and in an applied field in arbitrary direction, which answers the question whether long-range magnetization can indeed survive in the ultrathin limit of materials, up to which temperature, and what the characteristic excitation (magnon) frequencies are, all essential to envisaged applications of magnetic 2D materials. We find that long-range magnetic order persists at finite temperature for materials with overall easy-axis anisotropy. We validate the calculations on the examples of monolayers CrI3, CrBr3, and MnSe2. Moreover, we provide an easy-to-use tool to calculate Curie temperatures of new 2D computational materials. |
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Thesis |
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Place of Publication |
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Wos |
000559330100001 |
Publication Date |
2020-08-03 |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0003-6951; 1077-3118 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
4 |
Times cited |
8 |
Open Access |
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| Notes |
; This work was supported by the Research Foundation-Flanders (FWO) and the special research funds of the University of Antwerp (BOF-UA). ; |
Approved |
Most recent IF: 4; 2020 IF: 3.411 |
| Call Number |
UA @ admin @ c:irua:171176 |
Serial |
6445 |
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| Author |
Sabani, D.; Bacaksiz, C.; Milošević, M.V. |
| Title |
Ab initio methodology for magnetic exchange parameters: Generic four-state energy mapping onto a Heisenberg spin Hamiltonian |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Physical Review B |
Abbreviated Journal |
Phys Rev B |
| Volume |
102 |
Issue |
1 |
Pages |
014457-14458 |
| Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
| Abstract |
The recent development in the field of two-dimensional magnetic materials urges reliable theoretical methodology for determination of magnetic properties. Among the available methods, ab initio four-state energy mapping based on density functional theory stands out as a powerful technique to calculate the magnetic exchange interaction in the Heisenberg spin model. Although the required formulas were explained in earlier works, the considered Hamiltonian in those studies always corresponded to the specific case that the off-diagonal part of J matrix is antisymmetric, which may be misleading in other cases. Therefore, using the most general form of the Heisenberg spin Hamiltonian, we here derive the generic formulas. With a proper choice of four different magnetic states, a single formula governs all elements of the exchange interaction matrix for any considered pair of spin sites. |
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Place of Publication |
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Editor |
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Wos |
000554409500002 |
Publication Date |
2020-07-31 |
| 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 |
3.7 |
Times cited |
13 |
Open Access |
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| Notes |
; This work was supported by the Research Foundation-Flanders (FWO-Vlaanderen) and the Special Research Funds of the University of Antwerp (TOPBOF). The computational resources and services used in this work were provided by the VSC (Flemish Supercomputer Center), funded by the Research Foundation-Flanders (FWO-Vlaanderen) and the Flemish Government, Department EWI. ; |
Approved |
Most recent IF: 3.7; 2020 IF: 3.836 |
| Call Number |
UA @ admin @ c:irua:171203 |
Serial |
6448 |
| Permanent link to this record |
