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Author Li, L.L.; Moldovan, D.; Xu, W.; Peeters, F.M.
Title Electronic properties of bilayer phosphorene quantum dots in the presence of perpendicular electric and magnetic fields Type A1 Journal article
Year 2017 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 96 Issue (down) 15 Pages 155425
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Using the tight-binding approach, we investigate the electronic properties of bilayer phosphorene (BLP) quantum dots (QDs) in the presence of perpendicular electric and magnetic fields. Since BLP consists of two coupled phosphorene layers, it is of interest to examine the layer-dependent electronic properties of BLP QDs, such as the electronic distributions over the two layers and the so-produced layer-polarization features, and to see how these properties are affected by the magnetic field and the bias potential. We find that in the absence of a bias potential only edge states are layer polarized while the bulk states are not, and the layer-polarization degree (LPD) of the unbiased edge states increases with increasing magnetic field. However, in the presence of a bias potential both the edge and bulk states are layer polarized, and the LPD of the bulk (edge) states depends strongly (weakly) on the interplay of the bias potential and the interlayer coupling. At high magnetic fields, applying a bias potential renders the bulk electrons in a BLP QD to be mainly distributed over the top or bottom layer, resulting in layer-polarized bulk Landau levels (LLs). In the presence of a large bias potential that can drive a semiconductor-to-semimetal transition in BLP, these bulk LLs exhibit different magnetic-field dependences, i.e., the zeroth LLs exhibit a linearlike dependence on the magnetic field while the other LLs exhibit a square-root-like dependence.
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Publisher American Physical Society Place of Publication New York, N.Y Editor
Language Wos 000412699800005 Publication Date 2017-10-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 28 Open Access
Notes ; This work was financially supported by the Flemish Science Foundation (FWO-Vl), the National Natural Science Foundation of China (Grant No. 11574319), and the Chinese Academy of Sciences. ; Approved Most recent IF: 3.836
Call Number UA @ lucian @ c:irua:146686 Serial 4782
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Author Li, Q.N.; Xu, W.; Xiao, Y.M.; Ding, L.; Van Duppen, B.; Peeters, F.M.
Title Optical absorption window in Na₃Bi based three-dimensional Dirac electronic system Type A1 Journal article
Year 2020 Publication Journal Of Applied Physics Abbreviated Journal J Appl Phys
Volume 128 Issue (down) 15 Pages 155707
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We present a detailed theoretical study of the optoelectronic properties of a Na3Bi based three-dimensional Dirac electronic system (3DDES). The optical conductivity is evaluated using the energy-balance equation derived from a Boltzmann equation, where the electron Hamiltonian is taken from a simplified k . p approach. We find that for short-wavelength irradiation, the optical absorption in Na3Bi is mainly due to inter-band electronic transitions. In contrast to the universal optical conductance observed for graphene, the optical conductivity for Na3Bi based 3DDES depends on the radiation frequency but not on temperature, carrier density, and electronic relaxation time. In the radiation wavelength regime of about 5 mu m, < lambda < 200 mu m, an optical absorption window is found. This is similar to what is observed in graphene. The position and width of the absorption window depend on the direction of the light polarization and sensitively on temperature, carrier density, and electronic relaxation time. Particularly, we demonstrate that the inter-band optical absorption channel can be switched on and off by applying the gate voltage. This implies that similar to graphene, Na3Bi based 3DDES can also be applied in infrared electro-optical modulators. Our theoretical findings are helpful in gaining an in-depth understanding of the basic optoelectronic properties of recently discovered 3DDESs.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000585807400004 Publication Date 2020-10-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-8979; 1089-7550 ISBN Additional Links UA library record; WoS full record
Impact Factor 3.2 Times cited 1 Open Access
Notes ; This work was supported by the National Natural Science Foundation of China (NNSFC Nos. U1930116, U1832153, 11764045, 11574319, and 11847054) and the Center of Science and Technology of Hefei Academy of Science (No. 2016FXZY002). Applied Basic Research Foundation of Department of Science and Technology of Yunnan Province (No. 2019FD134), the Department of Education of Yunnan Province (No. 2018JS010), the Young Backbone Teachers Training Program of Yunnan University, and the Department of Science and Technology of Yunnan Province are acknowledged. ; Approved Most recent IF: 3.2; 2020 IF: 2.068
Call Number UA @ admin @ c:irua:173591 Serial 6571
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Author Xu, W.; Dong, H.M.; Li, L.L.; Yao, J.Q.; Vasilopoulos, P.; Peeters, F.M.
Title Optoelectronic properties of graphene in the presence of optical phonon scattering Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 82 Issue (down) 12 Pages 125304-125304,9
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We study in detail the optoelectronic properties of graphene. Considering the electron interactions with photons and phonons, we employ the mass- and energy-balance equations to self-consistently evaluate the photoinduced carrier densities, the optical conductance, and the transmission coefficient in the presence of a linearly polarized radiation field. We demonstrate that the photoinduced carrier densities increase around the electron-photon-phonon resonant transition. They depend strongly on the radiation intensity and frequency, temperature, and dark carrier density. For short-wavelength radiation (L<3 μm), we obtain the universal optical conductance σ0=e2/(4ℏ). Importantly, there exists an optical-absorption window in the radiation wavelength range 4100 μm, which is induced by different transition energies required for interband and intraband optical absorption. The position and width of this window depend sensitively on the temperature and the carrier density of the system. These theoretical results are in line with recent experimental findings and indicate that graphene exhibits important features not only in the visible regime but also in the midinfrared bandwidth.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000281516500009 Publication Date 2010-09-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 28 Open Access
Notes ; This work was supported by the Chinese Academy of Sciences, National Natural Science Foundation of China, and Department of Science and Technology of Yunnan Province. ; Approved Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:84260 Serial 2496
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Author Xu, W.; Peeters, F.M.; Devreese, J.T.
Title Streaming-to-accumulation transition in a 2-dimensional electron-system in a polar semiconductor Type A1 Journal article
Year 1992 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 46 Issue (down) 12 Pages 7571-7580
Keywords A1 Journal article; Condensed Matter Theory (CMT); Theory of quantum systems and complex systems
Abstract Hot-electron transport is studied for a two-dimensional electron gas coupled to longitudinal-optical phonons in crossed electric and magnetic fields. At low electric and high magnetic fields the electrons are accumulated, while at high electric fields they are in a streaming state. We develop a streaming-to-accumulation transition model and compare the results with that from a Monte Carlo simulation.
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Publisher Place of Publication Lancaster, Pa Editor
Language Wos A1992JQ37800028 Publication Date 2002-07-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0163-1829;1095-3795; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.736 Times cited 13 Open Access
Notes Approved PHYSICS, APPLIED 28/145 Q1 #
Call Number UA @ lucian @ c:irua:103023 Serial 3174
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Author Man, L.F.; Xu, W.; Xiao, Y.M.; Wen, H.; Ding, L.; Van Duppen, B.; Peeters, F.M.
Title Terahertz magneto-optical properties of graphene hydrodynamic electron liquid Type A1 Journal article
Year 2021 Publication Physical Review B Abbreviated Journal Phys Rev B
Volume 104 Issue (down) 12 Pages 125420
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The discovery of the hydrodynamic electron liquid (HEL) in graphene [D. Bandurin et al., Science 351, 1055 (2016) and J. Crossno et al., Science 351, 1058 (2016)] has marked the birth of the solid-state HEL which can be probed near room temperature in a table-top setup. Here we examine the terahertz (THz) magneto-optical (MO) properties of a graphene HEL. Considering the case where the magnetic length l(B) = root h/eB is comparable to the mean-free path l(ee) for electron-electron interaction in graphene, the MO conductivities are obtained by taking a momentum balance equation approach on the basis of the Boltzmann equation. We find that when l(B) similar to l(ee), the viscous effect in a HEL can weaken significantly the THz MO effects such as cyclotron resonance and Faraday rotation. The upper hybrid and cyclotron resonance magnetoplasmon modes omega(+/-) are also obtained through the RPA dielectric function. The magnetoplasmons of graphene HEL at large wave-vector regime are affected by the viscous effect, and results in red-shifts of the magnetoplasmon frequencies. We predict that the viscosity in graphene HEL can affect strongly the magneto-optical and magnetoplasmonic properties, which can be verified experimentally.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000704419300004 Publication Date 2021-09-15
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 4 Open Access OpenAccess
Notes Approved Most recent IF: 3.836
Call Number UA @ admin @ c:irua:182518 Serial 7029
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Author Li, L.L.; Xu, W.; Peeters, F.M.
Title Optical conductivity of topological insulator thin films Type A1 Journal article
Year 2015 Publication Journal of applied physics Abbreviated Journal J Appl Phys
Volume 117 Issue (down) 117 Pages 175305
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We present a detailed theoretical study on the optoelectronic properties of topological insulator thin film (TITFs). The k . p approach is employed to calculate the energy spectra and wave functions for both the bulk and surface states in the TITF. With these obtained results, the optical conductivities induced by different electronic transitions among the bulk and surface states are evaluated using the energy-balance equation derived from the Boltzmann equation. We find that for Bi2Se3-based TITFs, three characteristic regimes for the optical absorption can be observed. (i) In the low radiation frequency regime (photon energy (h) over bar omega < 200 meV), the free-carrier absorption takes place due to intraband electronic transitions. An optical absorption window can be observed. (ii) In the intermediate radiation frequency regime (200 < (h) over bar omega < 300 meV), the optical absorption is induced mainly by interband electronic transitions from surface states in the valance band to surface states in the conduction band and an universal value sigma(0) = e(2) / (8<(h)over bar>) for the optical conductivity can be obtained. (iii) In the high radiation frequency regime ((h) over bar omega > 300 meV), the optical absorption can be achieved via interband electronic transitions from bulk and surface states in the valance band to bulk and surface states in the conduction band. A strong absorption peak can be observed. These interesting findings indicate that optical measurements can be applied to identify the energy regimes of bulk and surface states in the TITF. (C) 2015 AIP Publishing LLC.
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Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000354984100615 Publication Date 2015-05-06
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-8979;1089-7550; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.068 Times cited 9 Open Access
Notes ; This work was supported by the National Natural Science Foundation of China (Grant No. 11304316), Ministry of Science and Technology of China (Grant No. 2011YQ130018), Department of Science and Technology of Yunnan Province, and by the Chinese Academy of Sciences. ; Approved Most recent IF: 2.068; 2015 IF: 2.183
Call Number c:irua:126412 Serial 2473
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Author Zhao, C.X.; Xu, W.; Li, L.L.; Zhang, C.; Peeters, F.M.
Title Terahertz plasmon-polariton modes in graphene driven by electric field inside a Fabry-Perot cavity Type A1 Journal article
Year 2015 Publication Journal of applied physics Abbreviated Journal J Appl Phys
Volume 117 Issue (down) 117 Pages 223104
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We present a theoretical study on plasmon-polariton modes in graphene placed inside an optical cavity and driven by a source-to-drain electric field. The electron velocity and electron temperature are determined by solving self-consistently the momentum-and energy-balance equations in which electron interactions with impurities, acoustic-, and optic-phonons are included. Based on many-body self-consistent field theory, we develop a tractable approach to study plasmon-polariton in an electron gas system. We find that when graphene is placed inside a Fabry-Perot cavity, two branches of the plasmon-polariton modes can be observed and these modes are very much optic-or plasmon-like. The frequencies of these modes depend markedly on driving electric field especially at higher resonant frequency regime. Moreover, the plasmon-polariton frequency in graphene is in terahertz (THz) bandwidth and can be tuned by changing the cavity length, gate voltage, and driving electric field. This work is pertinent to the application of graphene-based structures as tunable THz plasmonic devices. (C) 2015 AIP Publishing LLC.
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Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000356176100004 Publication Date 2015-06-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-8979;1089-7550; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.068 Times cited 13 Open Access
Notes ; This work was supported by the Ministry of Science and Technology of China (Grant No. 2011YQ130018), Department of Science and Technology of Yunnan Province, and by the Chinese Academy of Sciences. F.M.P. was a specially appointed Professor for foreign expert at the Chinese Academy of Sciences. ; Approved Most recent IF: 2.068; 2015 IF: 2.183
Call Number c:irua:127076 Serial 3507
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Author Zhang, H.Y.; Xiao, Y.M.; N. Li, Q.; Ding, L.; Van Duppen, B.; Xu, W.; Peeters, F.M.
Title Anisotropic and tunable optical conductivity of a two-dimensional semi-Dirac system in the presence of elliptically polarized radiation Type A1 Journal article
Year 2022 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 105 Issue (down) 11 Pages 115423-115429
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We investigate the effect of ellipticity ratio of the polarized radiation field on optoelectronic properties of a two-dimensional (2D) semi-Dirac (SD) system. The optical conductivity is calculated within the energy balance equation approach derived from the semiclassical Boltzmann equation. We find that there exists the anisotropic optical absorption induced via both the intra-and interband electronic transition channels in the perpendicular xx and yy directions. Furthermore, we examine the effects of the ellipticity ratio, the temperature, the carrier density, and the band-gap parameter on the optical conductivity of the 2D SD system placed in transverse and vertical directions, respectively. It is shown that the ellipticity ratio, temperature, carrier density, and band-gap parameter can play the important roles in tuning the strength, peak position, and shape of the optical conductivity spectrum. The results obtained from this study indicate that the 2D SD system can be a promising anisotropic and tunable optical and optoelectronic material for applications in innovative 2D optical and optoelectronic devices, which are active in the infrared and terahertz bandwidths.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000802810700002 Publication Date 2022-03-22
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.7 Times cited 3 Open Access OpenAccess
Notes Approved Most recent IF: 3.7
Call Number UA @ admin @ c:irua:188660 Serial 7125
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Author Zhao, X.N.; Xu, W.; Xiao, Y.M.; Van Duppen, B.
Title Spin polarization in monolayer MoS₂ in the presence of proximity-induced interactions Type A1 Journal article
Year 2020 Publication International Journal Of Modern Physics C Abbreviated Journal Int J Mod Phys C
Volume 31 Issue (down) 10 Pages 2050143
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract When monolayer (ML) MoS2 is placed on a substrate, the proximity-induced interactions such as the Rashba spin-orbit coupling (RSOC) and exchange interaction (EI) can be introduced. Thus, the electronic system can behave like a spintronic device. In this study, we present a theoretical study on how the presence of the RSCO and EI can lead to the band splitting, the lifting of the valley degeneracy and to the spin polarization in n- and p-type ML MoS2. We find that the maxima of the in-plane spin orientation in the conduction and valence bands in ML MoS2 depend on the Rashba parameter and the effective Zeeman field factor. At a fixed Rashba parameter, the minima of the split conduction band and the maxima of the split valence band along with the spin polarization in ML MoS2 can be tuned effectively by varying the effective Zeeman field factor. On the basis that the EI can be induced by placing the ML MoS2 on a ferromagnetic substrate or by magnetic doping in ML MoS2, we predict that the interesting spintronic effects can be observed in n- and p-type ML MoS2. This work can be helpful to gain an in-depth understanding of the basic physical properties of ML MoS2 for application in advanced electronic and optoelectronic devices.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000583803200009 Publication Date 2020-06-09
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0129-1831 ISBN Additional Links UA library record; WoS full record
Impact Factor 1.9 Times cited Open Access
Notes ; This work was supported by the Ministry of Science and Technology of China (Grant No. 2011YQ130018), Department of Science and Technology of Yunnan Province and by the Chinese Academy of Sciences. ; Approved Most recent IF: 1.9; 2020 IF: 1.171
Call Number UA @ admin @ c:irua:173635 Serial 6609
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Author Xiao, Y.M.; Xu, W.; Zhang, Y.Y.; Peeters, F.M.
Title Optoelectronic properties of ABC-stacked trilayer graphene Type A1 Journal article
Year 2013 Publication Physica status solidi: B: basic research Abbreviated Journal Phys Status Solidi B
Volume 250 Issue (down) 1 Pages 86-94
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We present a theoretical study on the optoelectronic properties of ABC-stacked trilayer graphene (TLG). The optical conductance and light transmittance are evaluated through using the energy-balance equation derived from the Boltzmann equation for an air/graphene/dielectric-wafer system in the presence of linearly polarized radiation field. The results obtained from two band structure models are examined and compared. For short wavelength radiation, the universal optical conductance sigma(0) = 3e(2)/(4h) can be obtained. Importantly, there exists an optical absorption window in the radiation wavelength range 10-200 mu m, which is induced by different transition energies required for inter- and intra-band optical absorption channels. As a result, we find that the position and width of this window depend sensitively on temperature and carrier density of the system, especially the lower frequency edge. There is a small characteristic absorption peak at about 82 mu m where the largest interband transition states exist in the ABC-stacked TLG model, in contrast to the relatively smooth curves in a simplified model. These theoretical results indicate that TLG has some interesting and important physical properties which can be utilized to realize infrared or THz optoelectronic devices.
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Corporate Author Thesis
Publisher Place of Publication Berlin Editor
Language Wos 000313347500011 Publication Date 2012-08-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0370-1972; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.674 Times cited 6 Open Access
Notes ; This work was supported by the National Natural Science Foundation of China (grant no. 10974206), Department of Science and Technology of Yunnan Province, and by the Chinese Academy of Sciences. One of us (F.M.P.) was a Specially Appointed Foreign Professor of the Chinese Academy of Sciences. ; Approved Most recent IF: 1.674; 2013 IF: 1.605
Call Number UA @ lucian @ c:irua:110109 Serial 2495
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Author Li, L.L.; Partoens, B.; Xu, W.; Peeters, F.M.
Title Electric-field modulation of linear dichroism and Faraday rotation in few-layer phosphorene Type A1 Journal article
Year 2019 Publication 2D materials Abbreviated Journal 2D Mater
Volume 6 Issue (down) 1 Pages 015032
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Electro-optical modulators, which use an electric voltage (or an electric field) to modulate a beam of light, are essential elements in present-day telecommunication devices. Using a self-consistent tight-binding approach combined with the standard Kubo formula, we show that the optical conductivity and the linear dichroism of few-layer phosphorene can be modulated by a perpendicular electric field. We find that the field-induced charge screening plays a significant role in modulating the optical conductivity and the linear dichroism. Distinct absorption peaks are induced in the conductivity spectrum due to the strong quantum confinement along the out-of-plane direction and to the field-induced forbidden-to-allowed transitions. The field modulation of the linear dichroism becomes more pronounced with increasing number of phosphorene layers. We also show that the Faraday rotation is present in few-layer phosphorene even in the absence of an external magnetic field. This optical Hall effect is induced by the reduced lattice symmetry of few-layer phosphorene. The Faraday rotation is greatly influenced by the field-induced charge screening and is strongly dependent on the strength of perpendicular electric field and on the number of phosphorene layers.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000454321100002 Publication Date 2018-11-28
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2053-1583 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.937 Times cited 23 Open Access
Notes ; This work was financially supported by the Flemish Science Foundation (FWO-Vl) and by the FLAG-ERA project TRANS-2D-TMD. ; Approved Most recent IF: 6.937
Call Number UA @ admin @ c:irua:156776 Serial 5207
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Author Dong, H.M.; Qin, H.; Zhang, J.; Peeters, F.M.; Xu, W.
Title Terahertz absorption window in bilayer graphene Type H1 Book chapter
Year 2009 Publication Abbreviated Journal
Volume Issue (down) Pages 247-248
Keywords H1 Book chapter; Condensed Matter Theory (CMT)
Abstract We present a detailed theoretical study of terahertz (THz) optical absorption in bilayer graphene. Considering an air/graphene/dielectric-wafer system, we find that there is an absorption window in the range 3 similar to 30 THz. Such an absorption window is induced by different transition energies required for inter- and intra-band optical absorption in the presence of the Pauli blockade effect. As a result, the position and width of this THz absorption window depend sensitively on temperature and carrier density of the system. These results are pertinent to the applications of recently developed graphene systems as novel optoelectronic devices such as THz photo-detectors.
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Corporate Author Thesis
Publisher Ieee Place of Publication New York, N.Y. Editor
Language Wos Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN 978-1-4244-5416-7 Additional Links UA library record; WoS full record;
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:99225 Serial 3506
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Author Ning, S.; Xu, W.; Ma, Y.; Loh, L.; Pennycook, T.J.; Zhou, W.; Zhang, F.; Bosman, M.; Pennycook, S.J.; He, Q.; Loh, N.D.
Title Accurate and Robust Calibration of the Uniform Affine Transformation Between Scan-Camera Coordinates for Atom-Resolved In-Focus 4D-STEM Datasets Type A1 Journal article
Year 2022 Publication Microscopy and microanalysis Abbreviated Journal Microsc Microanal
Volume Issue (down) Pages 1-11
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Accurate geometrical calibration between the scan coordinates and the camera coordinates is critical in four-dimensional scanning transmission electron microscopy (4D-STEM) for both quantitative imaging and ptychographic reconstructions. For atomic-resolved, in-focus 4D-STEM datasets, we propose a hybrid method incorporating two sub-routines, namely a J-matrix method and a Fourier method, which can calibrate the uniform affine transformation between the scan-camera coordinates using raw data, without a priori knowledge about the crystal structure of the specimen. The hybrid method is found robust against scan distortions and residual probe aberrations. It is also effective even when defects are present in the specimen, or the specimen becomes relatively thick. We will demonstrate that a successful geometrical calibration with the hybrid method will lead to a more reliable recovery of both the specimen and the electron probe in a ptychographic reconstruction. We will also show that, although the elimination of local scan position errors still requires an iterative approach, the rate of convergence can be improved, and the residual errors can be further reduced if the hybrid method can be firstly applied for initial calibration. The code is made available as a simple-to-use tool to correct affine transformations of the scan-camera coordinates in 4D-STEM experiments.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000767045700001 Publication Date 2022-03-09
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1431-9276 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.8 Times cited Open Access OpenAccess
Notes N. D. Loh kindly acknowledges support from NUS Early Career Research Award (R-154-000-B35-133), MOE’s AcRF Tier 1 grant nr. R-284-000-172-114 and NRF CRP grant number NRF-CRP16-2015-05. Q. He would also like to acknowledge the support of the National Research Foundation (NRF) Singapore, under its NRF Fellowship (NRF-NRFF11-2019-0002). W. Zhou acknowledges the support from Beijing Outstanding Young Scientist Program (BJJWZYJH01201914430039). F. Zhang acknowledges the support of the National Natural Science Foundation of China (11775105, 12074167). T. J. Pennycook acknowledges funding under the European Union’s Horizon 2020 research and innovation programme from the European Research Council (ERC) Grant agreement No. 802123-HDEM. Approved Most recent IF: 2.8
Call Number EMAT @ emat @c:irua:186958 Serial 6957
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Author Xu, W.; Van Alphen, S.; Galvita, V.V.; Meynen, V.; Bogaerts, A.
Title Effect of Gas Composition on Temperature and CO2Conversion in a Gliding Arc Plasmatron reactor: Insights for Post‐Plasma Catalysis from Experiments and Computation Type A1 Journal Article
Year 2024 Publication ChemSusChem Abbreviated Journal ChemSusChem
Volume Issue (down) Pages
Keywords A1 Journal Article; CO2 conversion · Plasma · Gliding arc plasmatron · Temperature profiles · Computational modelling; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Abstract Plasma‐based CO<sub>2</sub>conversion has attracted increasing interest. However, to understand the impact of plasma operation on post‐plasma processes, we studied the effect of adding N<sub>2</sub>, N<sub>2</sub>/CH<sub>4</sub>and N<sub>2</sub>/CH<sub>4</sub>/H<sub>2</sub>O to a CO<sub>2</sub>gliding arc plasmatron (GAP) to obtain valuable insights into their impact on exhaust stream composition and temperature, which will serve as feed gas and heat for post‐plasma catalysis (PPC). Adding N<sub>2</sub>improves the CO<sub>2</sub>conversion from 4 % to 13 %, and CH<sub>4</sub>addition further promotes it to 44 %, and even to 61 % at lower gas flow rate (6 L/min), allowing a higher yield of CO and hydrogen for PPC. The addition of H<sub>2</sub>O, however, reduces the CO<sub>2</sub>conversion from 55 % to 22 %, but it also lowers the energy cost, from 5.8 to 3 kJ/L. Regarding the temperature at 4.9 cm post‐plasma, N<sub>2</sub>addition increases the temperature, while the CO<sub>2</sub>/CH<sub>4</sub>ratio has no significant effect on temperature. We also calculated the temperature distribution with computational fluid dynamics simulations. The obtained temperature profiles (both experimental and calculated) show a decreasing trend with distance to the exhaust and provide insights in where to position a PPC bed.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001200297300001 Publication Date 2024-04-11
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1864-5631 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 8.4 Times cited Open Access
Notes We acknowledge the VLAIO Catalisti Moonshot project D2M and the VLAIO Catalisti transition project CO2PERATE (HBC.2017.0692) for financial support. We acknowledge Gilles Van Loon for his help to make the quartz and steel devices for the reactor. Vladimir V. Galvita also acknowledges a personal grant from the Research Fund of Ghent University (BOF; 01N16319). Approved Most recent IF: 8.4; 2024 IF: 7.226
Call Number PLASMANT @ plasmant @c:irua:205101 Serial 9128
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Author Xu, W.; Buelens, L.C.; Galvita, V.V.; Bogaerts, A.; Meynen, V.
Title Improving the performance of gliding arc plasma-catalytic dry reforming via a new post-plasma tubular catalyst bed Type A1 Journal Article
Year 2024 Publication Journal of CO2 Utilization Abbreviated Journal Journal of CO2 Utilization
Volume 83 Issue (down) Pages 102820
Keywords A1 Journal Article; Dry reforming Gliding arc plasma Plasma catalytic DRM Ni-based mixed oxide Post-plasma catalysis; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Abstract A combination of a gliding arc plasmatron (GAP) reactor and a newly designed tubular catalyst bed (N-bed) was applied to investigate the post-plasma catalytic (PPC) effect for dry reforming of methane (DRM). As comparison, a traditional plasma catalyst bed (T-bed) was also utilized. The post-plasma catalytic effect of a Ni-based mixed oxide (Ni/MO) catalyst with a thermal catalytic performance of 77% CO2 and 86% CH4 conversion at 700 ℃ was studied. Although applying the T-bed had little effect on plasma based CO2 and CH4 conversion, an increase in selectivity to H2 was obtained with a maximum value of 89% at a distance of 2 cm. However, even when only α-Al2O3 packing material was used in the N-bed configuration, compared to the plasma alone and the T-bed, an increase of the CO2 and CH4 conversion from 53% and 53% to 69% and 69% to 83% was achieved. Addition of the Ni/MO catalyst further enhanced the DRM reaction, resulting in conversions of 79% for CO2 and 91% for

CH4. Hence, although no insulation nor external heating was applied to the N-bed post plasma, it provides a slightly better conversion than the thermal catalytic performance with the same catalyst, while being fully electrically driven. In addition, an enhanced CO selectivity to 96% was obtained and the energy cost was reduced from ~ 6 kJ/L (plasma alone) to 4.3 kJ/L. To our knowledge, it is the first time that a post-plasma catalytic system achieves this excellent catalytic performance for DRM without extra external heating or insulation.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date 2024-05-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2212-9820 ISBN Additional Links
Impact Factor 7.7 Times cited Open Access
Notes Wencong Xu, Vladimir V. Galvita, Annemie Bogaerts, and Vera Meynen would like to acknowledge the VLAIO Catalisti Moonshot project D2M and the VLAIO Catalisti transition project CO2PERATE (HBC.2017.0692). Lukas C. Buelens acknowledges financial support from the Fund for Scientific Research Flanders (FWO Flanders) through a postdoctoral fellowship grant 12E5623N. Vladimir V. Galvita also acknowledges a personal grant from the Research Fund of Ghent University (BOF; 01N16319). Approved Most recent IF: 7.7; 2024 IF: 4.292
Call Number PLASMANT @ plasmant @ Serial 9131
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Author Leadley, D.R.; Nicholas, R.J.; Singleton, J.; Xu, W.; Peeters, F.M.; Devreese, J.T.; Perenboom, J.A.A.J.; van Bockstal, L.; Herlach, F.; Harris, J.J.; Foxon, C.T.
Title Collapse of high field magnetophonon resonance in GaAs-GaAlAs heterojunctions Type A1 Journal article
Year 1994 Publication Physical review letters Abbreviated Journal Phys Rev Lett
Volume 73 Issue (down) Pages 589-592
Keywords A1 Journal article; Condensed Matter Theory (CMT); Theory of quantum systems and complex systems
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos A1994NZ23700021 Publication Date 2002-07-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-9007; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 7.512 Times cited 24 Open Access
Notes Approved no
Call Number UA @ lucian @ c:irua:9278 Serial 383
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Author Xu, W.; Peeters, F.M.; Devreese, J.T.; Leadley, D.R.; Nicholas, R.J.
Title Destruction of magnetophonon resonance in high magnetic fields from impurity and phonon scattering in heterojunctions Type A1 Journal article
Year 1996 Publication International journal of modern physics: B: condensed matter physics, statistical physics, applied physics Abbreviated Journal Int J Mod Phys B
Volume 10 Issue (down) Pages 169-202
Keywords A1 Journal article; Condensed Matter Theory (CMT); Theory of quantum systems and complex systems
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Singapore Editor
Language Wos A1996TR56200002 Publication Date 2004-10-12
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0217-9792;1793-6578; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 0.937 Times cited 11 Open Access
Notes Approved CHEMISTRY, PHYSICAL 54/144 Q2 # PHYSICS, ATOMIC, MOLECULAR & CHEMICAL 9/35 Q2 #
Call Number UA @ lucian @ c:irua:15803 Serial 664
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Author Xu, W.; Leadley, D.R.; Peeters, F.M.; Devreese, J.T.; Nicholas, R.J.; Harris, J.J.; Foxon, C.T.
Title Destruction of magnetophonon resonance in high mobility heterojunctions from competition between elastic and inelastic scattering Type P3 Proceeding
Year 1994 Publication Proceedings of the International Conference on the Physics of Semiconductors Abbreviated Journal
Volume 22 Issue (down) Pages 839-842
Keywords P3 Proceeding; Condensed Matter Theory (CMT); Theory of quantum systems and complex systems
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved no
Call Number UA @ lucian @ c:irua:9284 Serial 665
Permanent link to this record
 
 
Author Xu, W.; Peeters, F.M.; Devreese, J.T.
Title Diffusion-to-streaming transition in a two-dimensional electron system in a polar semiconductor Type A1 Journal article
Year 1991 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 43 Issue (down) Pages 14134-14141
Keywords A1 Journal article; Condensed Matter Theory (CMT); Theory of quantum systems and complex systems
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos A1991FQ97400035 Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121; 0163-1829 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.736 Times cited 24 Open Access
Notes Approved no
Call Number UA @ lucian @ c:irua:913 Serial 701
Permanent link to this record
 
 
Author Leadley, D.R.; Nicholas, R.J.; Singleton, J.; Xu, W.; Peeters, F.M.; Devreese, J.T.; van Bockstal, L.; Herlach, F.; Perenboom, J.A.A.J.; Harris, J.J.; Foxon, C.T.
Title Disappearance of magnetophonon resonance at high magnetic fields in GaAs-GaAlAs heterojunctions Type A1 Journal article
Year 1994 Publication Surface science : a journal devoted to the physics and chemistry of interfaces Abbreviated Journal Surf Sci
Volume 305 Issue (down) Pages 327-331
Keywords A1 Journal article; Condensed Matter Theory (CMT); Theory of quantum systems and complex systems
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos A1994ND67400061 Publication Date 2002-10-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0039-6028; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.925 Times cited 1 Open Access
Notes Approved
Call Number UA @ lucian @ c:irua:9280 Serial 728
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Author Leadley, D.R.; Nicholas, R.J.; Xu, W.; Peeters, F.M.; Devreese, J.T.; Foxon, C.T.; Harris, J.J.
Title High-field magneto-resistance in GaAs-GaAlAs heterojunctions Type A1 Journal article
Year 1993 Publication Physica: B : condensed matter Abbreviated Journal Physica B
Volume 184 Issue (down) Pages 197-201
Keywords A1 Journal article; Condensed Matter Theory (CMT); Theory of quantum systems and complex systems
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos A1993KU62100039 Publication Date 2002-10-17
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0921-4526; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.319 Times cited 4 Open Access
Notes Approved
Call Number UA @ lucian @ c:irua:5746 Serial 1428
Permanent link to this record
 
 
Author Xu, W.; Peeters, F.M.; Devreese, J.T.
Title The hot electron distribution of two-dimensional electrons in a polar semiconductor at zero temperature Type A3 Journal article
Year 1991 Publication Journal of physics: C: condensed matter Abbreviated Journal
Volume 3 Issue (down) Pages 1783-1791
Keywords A3 Journal article; Condensed Matter Theory (CMT); Theory of quantum systems and complex systems
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos A1991FE35700009 Publication Date 0000-00-00
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 1 Open Access
Notes Approved no
Call Number UA @ lucian @ c:irua:948 Serial 1490
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Author Xiao, Y.M.; Xu, W.; Peeters, F.M.
Title Infrared to terahertz absorption window in mono- and multi-layer graphene systems Type A1 Journal article
Year 2014 Publication Optics communications Abbreviated Journal Opt Commun
Volume 328 Issue (down) Pages 135-142
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We present a theoretical study on optical properties such as optical conductance and light transmission coefficient for mono- and multi-layer graphene systems with AB- and ABC-stacking. Considering an air/graphene/dielectric-water structure, the optical coefficients for those graphene systems are examined and compared. The universal optical conductance sigma(N)(0)=N pi e(2)/(2h) for N layer graphene systems in the visible region is verified. For N 3 layer graphene, the mini-gap induced absorption edges can be observed in odd layers AB-stacked multilayer graphene, where the number and position of the absorption edges are decided by the layers number N. Meanwhile, we can observe the optical absorption windows for those graphene systems in the infrared to terahertz bandwidth (0.2-150 THz). The absorption window is induced by different transition energies required for inter- and intra-band optical absorption channels. We find that the depth and width of the absorption window can be tuned not only via varying temperature and electron density but also by changing the number of graphene layers and the stacking order. These theoretical findings demonstrate that mono- and multi-layer graphene systems can be applied as frequency tunable optoelectronic devices working in infrared to terahertz bandwidth. (C) 2014 Elsevier B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000336970000022 Publication Date 2014-05-14
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0030-4018; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.588 Times cited 7 Open Access
Notes ; This work was supported by the Ministry of Science and Technology of China (Grant no, 2011YQ130018), Department of Science and Technology of Yunnan Province, and by the Chinese Academy of Sciences. ; Approved Most recent IF: 1.588; 2014 IF: 1.449
Call Number UA @ lucian @ c:irua:118364 Serial 1666
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Author Xu, W.; Vasilopoulos, P.; Das, M.P.; Peeters, F.M.
Title The low-temperature self-consistent g factor for heterostructures in strong magnetic fields Type A1 Journal article
Year 1995 Publication Journal of physics : condensed matter Abbreviated Journal J Phys-Condens Mat
Volume 7 Issue (down) Pages 4419-4432
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos A1995RC23600011 Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0953-8984 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.346 Times cited 20 Open Access
Notes Approved no
Call Number UA @ lucian @ c:irua:12196 Serial 1853
Permanent link to this record
 
 
Author Xu, W.; Vasilopoulos, P.; Das, M.P.; Peeters, F.M.
Title Self-consistent g* factor and spin-split Landau levels in strong magnetic fields and at low temperatures Type P3 Proceeding
Year 1995 Publication Abbreviated Journal
Volume Issue (down) Pages 743-746
Keywords P3 Proceeding; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher World Scientific Place of Publication Singapore Editor
Language Wos Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved MATERIALS SCIENCE, MULTIDISCIPLINARY 96/271 Q2 #
Call Number UA @ lucian @ c:irua:12203 Serial 2974
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Author Xu, W.; Peeters, F.M.; Devreese, J.T.
Title Warm-electron transport in a two-dimensional semiconductor Type A1 Journal article
Year 1992 Publication Semiconductor science and technology Abbreviated Journal Semicond Sci Tech
Volume 7 Issue (down) Pages 1251-1256
Keywords A1 Journal article; Condensed Matter Theory (CMT); Theory of quantum systems and complex systems
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos A1992JT73000006 Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0268-1242 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.19 Times cited 3 Open Access
Notes Approved no
Call Number UA @ lucian @ c:irua:2915 Serial 3903
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Author Zhou, S.; Xu, W.; Xiao, Y.; Xiao, H.; Zhang, J.; Wang, Z.; He, G.; Liu, J.; Li, Y.; Peeters, F.M.
Title Influence of neutron irradiation on X-ray diffraction, Raman spectrum and photoluminescence from pyrolytic and hot-pressed hexagonal boron nitride Type A1 Journal article
Year 2023 Publication Journal of luminescence Abbreviated Journal
Volume 263 Issue (down) Pages 120118-8
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Hexagonal boron nitride (hBN) is considered as an ideal semiconductor material for solid-state neutron detector, owing to its large neutron scattering section because of the low atomic number of B and excellent physical properties. Here we study the influence of neutron irradiation on crystal structure and on intermediate energy state (IMES) levels induced by the presence of impurities and defects in hBN. Large-size and thick pyrolytic and hot-pressed hBN (PBN and HBN) samples, which can be directly applied for neutron detector devices, are prepared and bombarded by neutrons with different irradiation fluences. The SEM and TEM are used to observe the sample difference of PBN and HBN. X-ray diffraction and Raman spectroscopy are applied to examine the influence of neutron irradiation on lattice structures along different crystal directions of PBN and HBN samples. Photoluminescence (PL) is employed to study the effect of neutron irradiation on IMESs in these samples. We find that the neutron irradiation does not alter the in-plane lattice structures of both PBN and HBN samples, but it can release the inter-layer tensions induced by sample growth of the PBN samples. Interestingly and surprisingly, the neutron irradiation does not affect the IMES levels responsible for PL generation, where PL is attributed mainly from phonon-assisted radiative electron-hole coupling for both PBN and HBN samples. Furthermore, the results indicate that the neutron irradiation can weaken the effective carrier-phonon coupling and exciton transitions in PBN and HBN samples. Overall, both PBN and HBN samples show some degree of the resistance to neutron irradiation in terms of these basic physical properties. The interesting and important findings from this work can help us to gain an in-depth understanding of the influence of neutron irradiation on basic physical properties of hBN materials. These effects can be taken into account when designing and applying the hBN materials for neutron detectors.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001077086300001 Publication Date 2023-08-09
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-2313 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.6 Times cited 1 Open Access
Notes Approved Most recent IF: 3.6; 2023 IF: 2.686
Call Number UA @ admin @ c:irua:200393 Serial 9047
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Author Xu, W.
Title Plasma-catalytic DRM : study of LDH derived catalyst for DRM in a GAP plasma system Type Doctoral thesis
Year 2023 Publication Abbreviated Journal
Volume Issue (down) Pages 350 p.
Keywords Doctoral thesis; Laboratory of adsorption and catalysis (LADCA); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Plasma is considered one of the promising technologies to solve greenhouse gas problems, as it can activate CO2 and CH4 at relatively low temperatures. Among the various types of plasmas, the gliding arc plasmatron (GAP) is promising, as it has a high level of non-equilibrium and high electron density. Nevertheless, the conversion of CO2 and CH4 in the GAP reactor is limited. Therefore, combining the GAP reactor with catalysts and making use of the heat produced by the plasma to provide thermal energy to the catalyst, forming a post-plasma catalytic (PPC) system, is hypothesized to improve its performance. Therefore, in this PhD research, we investigate important aspects of the PPC concept towards the use of the heat produced by GAP plasma to heat the plasma bed, without additional energy input. Aiming at this, based on a literature study (chapter 1), Ni-loaded layered double hydroxide (LDH) derived catalyst with good thermal catalytic DRM performance were chosen as the catalyst material. Before applying the LDH as a support material, the rehydration property of calcined LDH in moist and liquid environment was studied as part of chapter 2. The data indicated that after high temperatures calcination (600-900 C), the obtained layered double oxides (LDOs) can rehydrate into LDH, although, the rehydrated LDH were different from the original LDH. In chapter 3, different operating conditions, such as gas flow rate, gas compositions (e.g. CH4/CO2 ratio and nitrogen dilution), and addition of H2O were studied to investigate optimal conditions for PPC DRM, identifying possible differences in temperature profiles and exhaust gas compositions that might influence the catalytic performance. Subsequently, the impact of different PPC configurations, making use of the heat and exhaust gas composition produced by the GAP plasma, is shown in Chapter 4. Experiments studying the impact of adjusting the catalyst bed distance to the post-plasma, the catalyst amount, the influence of external heating (below 250 C) and the addition of H2O are discussed. As only limited improvement in the performance was achieved, a new type of catalyst bed was designed and utilized, as described in chapter 5. This improved configuration can realize better heat and mass transfer by directly connecting to the GAP device. The performance was improved and became comparable to the traditional thermal catalytic DRM results obtained at 800 C, although obtained by a fully electrically driven plasma.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:201534 Serial 9074
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Author Xiao, H.; Zhang, Z.; Xu, W.; Wang, Q.; Xiao, Y.; Ding, L.; Huang, J.; Li, H.; He, B.; Peeters, F.M.
Title Terahertz optoelectronic properties of synthetic single crystal diamond Type A1 Journal article
Year 2023 Publication Diamond and related materials Abbreviated Journal
Volume 139 Issue (down) Pages 110266-110268
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract A systematic investigation is undertaken for studying the optoelectronic properties of single crystal diamond (SCD) grown by microwave plasma chemical vapor deposition (MPCVD). It is indicated that, without intentional doping and surface treatment during the sample growth, the terahertz (THz) optical conduction in SCD is mainly affected by surface H-terminations, -OH-, O- and N-based functional groups. By using THz time-domain spectroscopy (TDS), we measure the transmittance, the complex dielectric constant and optical conductivity σ(ω) of SCD. We find that SCD does not show typical semiconductor characteristics in THz regime, where σ(ω) cannot be described rightly by the conventional Drude formula. Via fitting the real and imaginary parts of σ(ω) to the Drude-Smith formula, the ratio of the average carrier density to the effective electron mass γ = ne/m*, the electronic relaxation time τ and the electronic backscattering or localization factor can be determined optically. The temperature dependence of these parameters is examined. From the temperature dependence of γ, a metallic to semiconductor transition is observed at about T = 10 K. The temperature dependence of τ is mainly induced by electron coupling with acoustic-phonons and there is a significant effect of photon-induced electron backscattering or localization in SCD. This work demonstrates that THz TDS is a powerful technique in studying SCD which contains H-, N- and O-based bonds and has low electron density and high dc resistivity. The results obtained from this study can benefit us to gain an in-depth understanding of SCD and may provide new guidance for the application of SCD as electronic, optical and optoelectronic materials.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date 2023-08-02
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0925-9635 ISBN Additional Links UA library record
Impact Factor 4.1 Times cited Open Access
Notes Approved Most recent IF: 4.1; 2023 IF: 2.561
Call Number UA @ admin @ c:irua:200920 Serial 9103
Permanent link to this record
 
 
Author Zhou, S.; Zhang, C.; Xu, W.; Zhang, J.; Xiao, Y.; Ding, L.; Wen, H.; Cheng, X.; Hu, C.; Li, H.; Li, X.; Peeters, F.M.
Title Observation of temperature induced phase transitions in TiO superconducting thin film via infrared measurement Type A1 Journal article
Year 2024 Publication Infrared physics and technology Abbreviated Journal
Volume 137 Issue (down) Pages 105160-105169
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract In contrast to conventional polycrystalline titanium oxide (TiO), it was found recently that the superconducting transition temperature Tc can be significantly enhanced from about 2 K to 7.4 K in cubic TiO thin films grown epitaxially on alpha-Al2O3 substrates. This kind of TiO film is also expected to have distinctive optoelectronic properties, which are still not very clear up to now. Herein, by using infrared (IR) reflection measurement we investigate the temperature-dependent optoelectronic response of a cubic TiO thin film, in which temperature induced phase transitions are observed. The semiconductor-, metallic- and semiconductor-like electronic phases of this superconducting film are found in the temperature regimes from 10 to 110 K, 110 to 220 K and above 220 K, respectively. The results obtained optically are consistent with those measured by transport experiment. Furthermore, based on an improved reflection model developed here, we extract the complex optical conductivity of the cubic TiO thin film. We are able to approximately determine the characteristic parameters (e.g., effective electron mass, carrier density, scattering time, etc.) for different electronic phases by fitting the optical conductivity with the modified Lorentz formula. These results not only deepen our understanding of the fundamental physics for cubic TiO thin films but also may find applications in optoelectronic devices based on superconductors.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001170490200001 Publication Date 2024-01-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1350-4495 ISBN Additional Links UA library record; WoS full record
Impact Factor 3.3 Times cited Open Access
Notes Approved Most recent IF: 3.3; 2024 IF: 1.713
Call Number UA @ admin @ c:irua:204853 Serial 9162
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