1. 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, izvirni znanstveni članek Opis: 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.
Ključne besede: density functional theory, electronic band structure, topological insulators, work functions, scanning tunneling microscopy, atomic structure, antimony, angle-resolved photoemission spectroscopy, core level shifts
Objavljeno v RUNG: 20.03.2025; Ogledov: 193; Prenosov: 4
 Celotno besedilo (2,71 MB)
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2. Single crystal synthesis and surface electronic structure of Bi_{1.993}Cr_{0.007}Se_{3}Sandra Gardonio, Zipporah Rini Benher, Mattia Fanetti, Paolo Moras, Polina M. Sheverdyaeva, Matjaž Valant, 2024, izvirni znanstveni članek Ključne besede: topological insulators, magnetic atoms, crystal synthesis, formation of clusters, surface electronic structure
Objavljeno v RUNG: 21.08.2024; Ogledov: 1220; Prenosov: 8
Celotno besedilo (2,05 MB)
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3. 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, izvirni znanstveni članek Ključne besede: density functional theory, spin-resolved ARPES, electronic structure, topological insulators, 2D materials, antimonene
Objavljeno v RUNG: 18.07.2023; Ogledov: 2424; Prenosov: 5
Celotno besedilo (4,26 MB)
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4. Electronic and chemical surface properties of Bi2Se3 derived compoundsZipporah Rini Benher, doktorska disertacija Ključne besede: Bismuth selenide derived compounds, surface chemical and electronic properties, topological insulators, single crystals, phase separation, inorganic bulk heterostructures, ix
Bridgman method, X-ray powder diffraction, scanning electron microscopy, photoelectron spectroscopy
Objavljeno v RUNG: 16.12.2022; Ogledov: 3380; Prenosov: 32
Celotno besedilo (9,56 MB) |
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6. Electronic properties of phases in the quasi-binary Bi[sub]2Se[sub]3-Bi[sub]2S[sub]3 systemZipporah Rini Benher, Sandra Gardonio, Mattia Fanetti, Paolo Moras, Asish K. Kundu, Chiara Bigi, Matjaž Valant, 2021, izvirni znanstveni članek Opis: We explored the properties of the quasi-binary Bi2Se3–Bi2S3 system over a wide compositional range. X-ray diffraction analysis demonstrates that rhombohedral crystals can be synthesized within the solid solution interval 0–22 mol% Bi2S3, while at 33 mol% Bi2S3 only orthorhombic crystals are obtained. Core level photoemission spectroscopy reveals the presence of Bi3+, Se2− and S2− species and the absence of metallic species, thus indicating that S incorporation into Bi2Se3 proceeds prevalently through the substitution of Se with S. Spin- and angle-resolved photoemission spectroscopy shows that topological surface states develop on the surfaces of the Bi2Se3−ySy (y ≤0.66) rhombohedral crystals, in close analogy with the prototypical case of Bi2Se3, while the orthorhombic crystals with higher S content turn out to be trivial semiconductors. Our results connect unambiguously the phase diagram and electronic properties of the Bi2Se3–Bi2S3 system.
Ključne besede: topological insulator, quasi-binary Bi2Se3-Bi2S3 system, electronic properties
Objavljeno v RUNG: 29.03.2021; Ogledov: 3474; Prenosov: 0
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7. Looking for a topological insulator in the tetradymite familyZipporah Rini Benher, Sandra Gardonio, Mattia Fanetti, Polina M. Sheverdyaeva, Paolo Moras, Matjaž Valant, 2019, objavljeni povzetek znanstvenega prispevka na konferenci Opis: Materials that are topological insulators (TI) manifest a novel state for their electrons. They possess topological surface states that are not destroyed by the presence of non-magnetic impurities on their surfaces. This unique property lies in the bulk band structure and it is typically found in narrow gap semiconductor with strong spin-orbit coupling.
Bi2Se3 and Bi2Te3 belong to the class of compounds called tetradymites and are considered as the 3D-prototypical TI materials. However, these compounds are not usually insulators but have metallic bulk conductivity as a consequence of intrinsic defect doping: vacancies and anti-site defects. For these reasons, it is difficult to electrically gate these materials for the manipulation and control of charge carriers for realizing devices. This led to the search for other topological materials, which might have better insulating behavior in their bulk.
Theoretical studies have pointed out that ternary variants of the Bi2Se3 and Bi2Te3, such as Bi2Te2Se, Bi2Te2S, Bi2Se2S Sb2Te2Se and Sb2Te2S, should be stable TIs and potentially offer a chemical way to control TI behavior, in particular by lowering native doping. Among the cited ternary compounds, Bi2Se2S should manifest a genuine topological spin-transport regime hosting an isolated Dirac cone with the Dirac point in the gap as well. However, it has been poorly studied from the TI experimental perspective.
Therefore, to uncover the full potential of the predicted topological electronic properties of the Bi-Se-S system, in this presentation we will revisit the crystallographic and electronic structure of Bi2Se3-Bi2S3 solid solutions. The combined use of bulk and surface sensitive techniques such as X-ray diffraction (XRD), low energy electron diffraction (LEED), scanning electron microscopy (SEM) with Energy Dispersive X-ray spectroscopy (EDX) and X-ray photoemission spectroscopy (XPS) was applied to analyze single crystal samples grown by us. The quality of the single crystals was suitable for rigorous measurement of the electronic properties by means of Angle Resolved Photoemission Spectroscopy. We unambiguously showed that within a certain solid solution range, the single crystals of Bi-Se-S have a rombohedral structure with the topological surface states as theoretically predicted.
Ključne besede: topological insulators, ternary tetradymite, electronic properties.
Objavljeno v RUNG: 19.12.2019; Ogledov: 5521; Prenosov: 0
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