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2. Mastering the growth of antimonene on ▫$Bi_2Se_3$▫ : strategies and insightsRoberto Flammini, Conor Hogan, Stefano Colonna, Fabio Ronci, Mauro Satta, Marco Papagno, Ziya S. Aliev, Sergey V. Eremeev, Zipporah Rini Benher, Sandra Gardonio, 2025, original scientific article Abstract: Antimonene, the two-dimensional phase of antimony, appears in two distinct allotropes when epitaxially grown on Bi2Se3: the puckered asymmetric washboard (α) and buckled honeycomb (β) bilayer structures. As-deposited antimony films exhibit varying proportions of single α and β structures. We identify the conditions necessary for ordered, pure-phase growth of single to triple β-antimonene bilayers. Additionally, we determine their electronic structure, work function, and characteristic core-level binding energies, offering an explanation for the relatively large chemical shifts observed among the different phases. This study not only establishes a protocol for achieving a single β phase of antimonene but also provides key signatures for distinguishing between the different allotropes using standard spectroscopic and microscopic techniques.
Keywords: density functional theory, electronic band structure, topological insulators, work functions, scanning tunneling microscopy, atomic structure, antimony, angle-resolved photoemission spectroscopy, core level shifts
Published in RUNG: 20.03.2025; Views: 1042; Downloads: 7
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3. Initial oxidation of low index Mg surfaces investigated by SCLS and DFTZhe Xing, Mattia Fanetti, Sandra Gardonio, Elsebeth Schröder, Dmytro Orlov, 2024, original scientific article Keywords: oxidation mechanism, surface core level shift, density functional theory, surface reconstruction, magnesium oxidation
Published in RUNG: 25.07.2024; Views: 2184; Downloads: 11
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4. Giant and tunable out-of-plane spin polarization of topological antimonenePolina M. Sheverdyaeva, Conor Hogan, Gustav Bihlmayer, Jun Fujii, Ivana Vobornik, Matteo Jugovac, Asish K. Kundu, Sandra Gardonio, Zipporah Rini Benher, Giovanni di Santo, 2023, original scientific article Keywords: density functional theory, spin-resolved ARPES, electronic structure, topological insulators, 2D materials, antimonene
Published in RUNG: 18.07.2023; Views: 3184; Downloads: 5
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5. Infrared spectra in amorphous alumina : a combined ab initio and experimental studyLuigi Giacomazzi, Nikita S. Shcheblanov, Mikhail E. Povarnitsyn, Yanbo Li, Andraž Mavrič, Barbara Zupančič, Jože Grdadolnik, Alfredo Pasquarello, 2023, original scientific article Abstract: We present a combined study based on the experimental measurements of an infrared (IR) dielectric function and first-principles calculations of IR spectra and the vibrational density of states (VDOS) of amorphous alumina (am−Al2O3). In particular, we show that the main features of the imaginary part of the dielectric function ε2(ω) at ∼380 and 630 cm−1 are related to the motions of threefold-coordinated oxygen atoms, which are the vast majority of oxygen atoms in am-Al2O3. Our analysis provides an alternative point of view with respect to an earlier suggested assignment of the vibrational modes, which relates them to the stretching and bending vibrational modes of AlOn (n=4, 5, and 6) polyhedra. Our assignment is based on the additive decomposition of the VDOS and ε2(ω) spectra, which shows that (i) the band at ∼380cm−1 features oxygen motions occurring in a direction normal to the plane defined by the three nearest-neighbor aluminum atoms, i.e., out-of-plane motions of oxygen atoms; (ii) Al-O stretching vibrations (i.e., in-plane motions of oxygen atoms) appear at frequencies above ∼500cm−1, which characterize the vibrational modes underlying the band at ∼630cm−1. Aluminum and fourfold-coordinated oxygen atoms contribute uniformly to the VDOS and ε2(ω) spectra in the frequency region ∼350–650 cm−1 without causing specific features. Our numerical results are in good agreement with the previous and presently obtained experimental data on the IR dielectric function of am−Al2O3 films. Finally, we show that the IR spectrum can be modeled successfully by assuming isotropic Born charges for aluminum atoms and fourfold-coordinated oxygen atoms, while requiring the use of three parameters, defined in a local reference frame, for the anisotropic Born charges of threefold-coordinated oxygen atoms.
Keywords: dielectric properties, microstructure, amorphous materials, density functional calculations, infrared techniques, aluminium oxide
Published in RUNG: 10.05.2023; Views: 3584; Downloads: 12
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6. Ultrafast relaxation of photoexcited superfluid He nanodropletsM. Mudrich, A.C. LaForge, A. Ciavardini, P. O'Keeffe, C. Callegari, M. Coreno, A. Demidovich, M. Devetta, M. Di Fraia, M. Drabbels, P. Finetti, O. Gessner, C. Grazioli, A. Hernando, D.M. Neumark, Y. Ovcharenko, P. Piseri, O. Plekan, K.C. Prince, R. Richter, M.P. Ziemkiewicz, T. Moller, J. Eloranta, M. Pi, M. Barranco, F. Stienkemeier, 2020, original scientific article Keywords: helium, helium nanodroplet, nanomaterial, density functional theory, dipole, excitation, ionization, photoelectron spectroscopy, photoexcitation, photon, simulation, ultraviolet radiation, ultrafast photoemission, free electron laser, ultrafast spectrscopy
Published in RUNG: 20.01.2022; Views: 3274; Downloads: 0
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7. Carbon and Nitrogen K-Edge NEXAFS Spectra of Indole, 2,3-Dihydro-7-azaindole, and 3-FormylindoleAurora Ponzi, Elisa Bernes, Daniele Toffoli, Giovanna Fronzoni, Carlo Callegari, Alessandra Ciavardini, Michele Di Fraia, Robert Richter, Kevin Charles Prince, Hanan Sa'adeh, Michele Devetta, Davide Faccialà, Caterina Vozzi, Lorenzo Avaldi, Paola Bolognesi, Mattea Castrovilli, Daniele Catone, Marcello Coreno, Oksana Plekan, 2021, original scientific article Keywords: Carbon and nitrogen, General description, Hybrid functional, Near-edge X-ray absorption fine structure spectrum, Relevant features, Rydberg character, Theoretical spectra, Time dependent density functional theory
Published in RUNG: 19.01.2022; Views: 3610; Downloads: 0
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10. Characterization of Mg low-index surfaces by first-principlesMiha Gunde, 2017, master's thesis Abstract: In this work, three surfaces, namely, Mg(0001), Mg(10 ̄1 0) and Mg(11 ̄2 0) are investigated by means of Density Functional Theory and Generalized Gradient Approximation first-principle calculations. The surfaces have been characterized in terms of their interlayer distances, surface energies, Projected Density of States and Surface Core Level Shifts. Contrary to what was found in previous studies based on Density Functional Theory-Local Density Approximation, the use of Generalized Gradient Approximation exchange correlation functional unravels the oscillatory behavior of both interlayer distances and Surface Core Level Shifts of Mg(10 ̄1 0). Moreover,
the Projected Density Of States of un-reconstructed Mg(11 ̄2 0) exhibit the typical quantisation of electronic levels associated to a 2D-confinement of a 3D nearly-free electron gas, as observed in nano-wires, and a Peierls instability along the unconfined direction. Different possible reconstructions on Mg(11 ̄2 0) have then been investigated. In particular, it is found that the
surface energy of (2X1) and (3X1) reconstructions is almost degenerate and lower than the surface energy of the unreconstructed Mg(11 ̄2 0) surface. Because of the quasi-degeneracy of surface energies, Mg(11 ̄2 0) surface should be composed by a combination of all the quasi degenerate phases.
Keywords: Density Functional Theory, first-principle calculations, Mg surface, Surface Core-Level Shift, surface relaxation, surface reconstruction
Published in RUNG: 04.07.2017; Views: 7935; Downloads: 2118
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