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| Author | Lima, I.L.C.; Milošević, M.V.; Peeters, F.M.; Chaves, A. | ||||
| Title | Tuning of exciton type by environmental screening | Type | A1 Journal article | ||
| Year | 2023 | Publication | Physical review B | Abbreviated Journal | |
| Volume | 108 | Issue | 11 | Pages | 115303-115308 |
| Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
Abstract  |
We theoretically investigate the binding energy and electron-hole (e-h) overlap of excitonic states confined at the interface between two-dimensional materials with type-II band alignment, i.e., with lowest conduction and highest valence band edges placed in different materials, arranged in a side-by-side planar heterostructure. We propose a variational procedure within the effective mass approximation to calculate the exciton ground state and apply our model to a monolayer MoS2/WS2 heterostructure. The role of nonabrupt interfaces between the materials is accounted for in our model by assuming a WxMo1-xS2 alloy around the interfacial region. Our results demonstrate that (i) interface-bound excitons are energetically favorable only for small interface thickness and/or for systems under high dielectric screening by the materials surrounding the monolayer, and that (ii) the interface exciton binding energy and its e-h overlap are controllable by the interface width and dielectric environment. | ||||
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| Language | Wos | 001077758300002 | Publication Date | 2023-09-08 | |
| 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 | |
| Impact Factor | 3.7 | Times cited | Open Access | ||
| Notes | Approved | Most recent IF: 3.7; 2023 IF: 3.836 | |||
| Call Number | UA @ admin @ c:irua:200356 | Serial | 9110 | ||
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| Author | De Beule, C.; Ziani, N.T.; Zarenia, M.; Partoens, B.; Trauzettel, B. | ||||
| Title | Correlation and current anomalies in helical quantum dots | Type | A1 Journal article | ||
| Year | 2016 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
| Volume | 94 | Issue | 94 | Pages | 155111 |
| Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
| Abstract |
We theoretically investigate the ground-state properties of a quantum dot defined on the surface of a strong three-dimensional time-reversal invariant topological insulator. Confinement is realized by ferromagnetic barriers and Coulomb interaction is treated numerically for up to seven electrons in the dot. Experimentally relevant intermediate interaction strengths are considered. The topological origin of the dot has several consequences: (i) spin polarization increases and the ground state exhibits quantum phase transitions at specific angular momenta as a function of interaction strength, (ii) the onset of Wigner correlations takes place mainly in one spin channel, and (iii) the ground state is characterized by a robust persistent current that changes sign as a function of the distance from the center of the dot. | ||||
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| Language | Wos | 000385242200001 | Publication Date | 2016-10-07 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9950;2469-9969; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 3 | Open Access | |
| Notes | ; We thank F. Cavaliere, F. Crepin, C. Felser, and B. Yan for interesting discussions, and S. Curreli for performing the finite-element calculation of the magnetic field in COMSOL. C.D.B. and M.Z. are supported by the Flemish Research Foundation (FWO). N.T.Z. and B.T. acknowledge financial support by the DFG (SPP1666 and SFB1170 “ToCoTronics”), the Helmholtz Foundation (VITI), and the ENB Graduate School on “Topological Insulators.” ; | Approved | Most recent IF: 3.836 | ||
| Call Number | UA @ lucian @ c:irua:137234 | Serial | 4351 | ||
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| Author | Van der Donck, M.; Peeters, F.M. | ||||
| Title | Rich many-body phase diagram of electrons and holes in doped monolayer transition metal dichalcogenides | Type | A1 Journal article | ||
| Year | 2018 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
| Volume | 98 | Issue | 11 | Pages | 115432 |
| Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
| Abstract |
We use a variational technique to study the many-body phase diagram of electrons and holes in n-doped and p-doped monolayer transition metal dichalcogenides (TMDs). We find a total of four different phases. (i) A fully spin polarized and valley polarized ferromagnetic state. (ii) A state with no global spin polarization but with spin polarization in each valley separately, i.e., spin-valley locking. (iii) A state with spin polarization in one of the valleys and little to no spin polarization in the other valley. (iv) A paramagnetic state with no valley polarization. These phases are separated by first-order phase transitions and are determined by the particle density and the dielectric constant of the substrate. We find that in the presence of a perpendicular magnetic field the four different phases persist. In the case of n-doped MoS2, a fifth phase, which is completely valley polarized but not spin polarized, appears for magnetic fields larger than 7 T and for magnetic fields larger than 23 T completely replaces the second phase. | ||||
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| Publisher | American Physical Society | Place of Publication | New York, N.Y | Editor | |
| Language | Wos | 000445507000009 | Publication Date | 2018-09-24 | |
| 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 | 8 | Open Access | |
| Notes | ; This work was supported by the Research Foundation of Flanders (FWO-Vl) through an aspirant research grant for MVDD and by the FLAG-ERA project TRANS-2D-TMD. ; | Approved | Most recent IF: 3.836 | ||
| Call Number | UA @ lucian @ c:irua:153622UA @ admin @ c:irua:153622 | Serial | 5125 | ||
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| Author | Bercx, M.; Partoens, B.; Lamoen, D. | ||||
| Title | Quantitative modeling of secondary electron emission from slow-ion bombardment on semiconductors | Type | A1 Journal article | ||
| Year | 2019 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
| Volume | 99 | Issue | 8 | Pages | 085413 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) | ||||
| Abstract |
When slow ions incident on a surface are neutralized, the excess potential energy is passed on to an electron inside the surface, leading to emission of secondary electrons. The microscopic description of this process, as well as the calculation of the secondary electron yield, is a challenging problem due to its complexity as well as its sensitivity to surface properties. One of the first quantitative descriptions was articulated in the 1950s by Hagstrum, who based his calculation on a parametrization of the density of states of the material. In this paper, we present a model for calculating the secondary electron yield, derived from Hagstrum’s initial approach. We use first-principles density functional theory calculations to acquire the necessary input and introduce the concept of electron cascades to Hagstrum’s model in order to improve the calculated spectra, as well as remove its reliance on fitting parameters. We apply our model to He+ and Ne+ ions incident on Ge(111) and Si(111) and obtain yield spectra that match closely to the experimental results of Hagstrum. |
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| Language | Wos | 000458367800010 | Publication Date | 2019-02-11 | |
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| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9950 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 5 | Open Access | OpenAccess |
| Notes | We would like to thank Prof. D. Depla for the useful discussions on the secondary electron yield. Furthermore, we acknowledge financial support of FWO-Vlaanderen through project G.0216.14N. The computational resources and services used in this work were provided by the VSC (Flemish Supercomputer Center) and the HPC infrastructure of the University of Antwerp (CalcUA), both funded by the FWOVlaanderen and the Flemish Government-department EWI. | Approved | Most recent IF: 3.836 | ||
| Call Number | EMAT @ emat @UA @ admin @ c:irua:157174 | Serial | 5154 | ||
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| Author | Mirzakhani, M.; Peeters, F.M.; Zarenia, M. | ||||
| Title | Circular quantum dots in twisted bilayer graphene | Type | A1 Journal article | ||
| Year | 2020 | Publication | Physical Review B | Abbreviated Journal | Phys Rev B |
| Volume | 101 | Issue | 7 | Pages | 075413 |
| Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
| Abstract |
Within a tight-binding approach, we investigate the effect of twisting angle on the energy levels of circular bilayer graphene (BLG) quantum dots (QDs) in both the absence and presence of a perpendicular magnetic field. The QDs are defined by an infinite-mass potential, so that the specific edge effects are not present. In the absence of magnetic field (or when the magnetic length is larger than the moire length), we show that the low-energy states in twisted BLG QDs are completely affected by the formation of moire patterns, with a strong localization at AA-stacked regions. When magnetic field increases, the energy gap of an untwisted BLG QD closes with the edge states, localized at the boundaries between the AA- and AB-stacked spots in a twisted BLG QD. Our observation of the spatial localization of the electrons in twisted BLG QDs can be experimentally probed by low-bias scanning tunneling microscopy measurements. | ||||
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| Language | Wos | 000512772200004 | Publication Date | 2020-02-13 | |
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| ISSN | 2469-9969; 2469-9950 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.7 | Times cited | 13 | Open Access | |
| Notes | ; We gratefully acknowledge discussions with I. Snyman. M.Z. acknowledges support from the U.S. Department of Energy (Office of Science) under Grant No. DE-FG0205ER46203. ; | Approved | Most recent IF: 3.7; 2020 IF: 3.836 | ||
| Call Number | UA @ admin @ c:irua:166493 | Serial | 6470 | ||
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| Author | Saberi-Pouya, S.; Vazifehshenas, T.; Salavati-Fard, T.; Farmanbar, M.; Peeters, F.M. | ||||
| Title | Strong anisotropic optical conductivity in two-dimensional puckered structures : the role of the Rashba effect | Type | A1 Journal article | ||
| Year | 2017 | Publication | Physical review B | Abbreviated Journal | Phys Rev B |
| Volume | 96 | Issue | 7 | Pages | 075411 |
| Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
| Abstract |
within the Kubo formalism. We show that the anisotropic Rashba effect caused by an external field significantly changes the magnitude of the spin splitting. Furthermore, we obtain an analytical expression for the longitudinal optical conductivity associated with interband transitions as a function of the frequency for arbitrary polarization angle. We find that the diagonal components of the optical conductivity tensor are direction dependent and the optical absorption spectrum exhibits a strongly anisotropic absorption window. The height and width of this absorption window are very sensitive to the anisotropy of the system. While the height of absorption peak increases with increasing effective mass anisotropy ratio, the peak intensity is larger when the light polarization is along the armchair direction. Moreover, the absorption peak width becomes broader as the density-of-states mass or Rashba interaction is enhanced. These features in the optical absorption spectrum can be used to determine parameters relevant for spintronics. | ||||
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| Publisher | American Physical Society | Place of Publication | New York, N.Y | Editor | |
| Language | Wos | 000407097100005 | Publication Date | 2017-08-09 | |
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| ISSN | 2469-9969; 2469-9950 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 16 | Open Access | |
| Notes | ; ; | Approved | Most recent IF: 3.836 | ||
| Call Number | UA @ lucian @ c:irua:145725 | Serial | 4752 | ||
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| Author | Zuniga-Puelles, E.; Levytskyi, V.; Özden, A.; Guerel, T.; Bulut, N.; Himcinschi, C.; Sevik, C.; Kortus, J.; Gumeniuk, R. | ||||
| Title | Thermoelectric properties and scattering mechanisms in natural PbS | Type | A1 Journal article | ||
| Year | 2023 | Publication | Physical review B | Abbreviated Journal | |
| Volume | 107 | Issue | 19 | Pages | 195203-195215 |
| Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
| Abstract |
X-ray diffraction and energy dispersive x-ray spectroscopic analyses showed a natural galena (PbS) crystal from Freiberg in Saxony (Germany) to be a single phase specimen [rock salt (NaCl) structure type, space group Fm3m, a = 5.932(1) angstrom] with stoichiometric composition and an enhanced dislocation density (8 approximate to 1011 cm-2). The latter parameter leads to an increase of the electrical resistivity in the high-temperature regime, as well as to the appearance of phonon resonance with a characteristic frequency coPR = 3.8(1) THz. Being in the same range (i.e., 3-5.5 THz) with the sulfur optical modes of highest group velocities, it results in a drastic reduction (by similar to 75%) of thermal conductivity (K) at lower temperatures (i.e., < 100 K), as well as in the appearance of a characteristic minimum in K at T approximate to 30 K. Furthermore, the studied galena is characterized by phonon-drag behavior and by temperature dependent switch of the charge carrier scattering mechanism regime (i.e., scattering on dislocations for T < 100 K, on acoustic phonons for 100 K < T < 170 K and on both acoustic and optical phonons for 170 K < T < 300 K). The combined theoretical calculation and optical spectroscopic study confirm this mineral to be a direct gap degenerate semiconductor. The possible origins of the second-order Raman spectrum are discussed. | ||||
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| Language | Wos | 001009980400008 | Publication Date | 2023-05-30 | |
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| 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 | Open Access | Not_Open_Access | |
| Notes | Approved | Most recent IF: 3.7; 2023 IF: 3.836 | |||
| Call Number | UA @ admin @ c:irua:197808 | Serial | 8943 | ||
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