Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 1Citation - Scopus: 1First-Principles Investigation of Structural, Raman and Electronic Characteristics of Single Layer Ge3n4(Elsevier, 2022) Yayak, Yankı Öncü; Sözen, Yiğit; Tan, Fırat; Güngen, Deniz; Gao, Q.; Kang, J.; Yağmurcukardeş, Mehmet; Şahin, HasanBy means of density functional theory-based first-principle calculations, the structural, vibrational and electronic properties of single-layer Ge3N4 are investigated. Structural optimizations and phonon band dispersions reveal that single-layer ultrathin form of Ge3N4 possesses a dynamically stable buckled structure with large hexagonal holes. Predicted Raman spectrum of single-layer Ge3N4 indicates that the buckled holey structure of the material exhibits distinctive vibrational features. Electronic band dispersion calculations indicate the indirect band gap semiconducting nature of single-layer Ge3N4. It is also proposed that single-layer Ge3N4 forms type-II vertical heterostructures with various planar and puckered 2D materials except for single-layer GeSe which gives rise to a type-I band alignment. Moreover, the electronic properties of single-layer Ge3N4 are investigated under applied external in-plane strain. It is shown that while the indirect gap behavior of Ge3N4 is unchanged by the applied strain, the energy band gap increases (decreases) with tensile (compressive) strain. © 2021 Elsevier B.V.Article Citation - WoS: 15Citation - Scopus: 18Computing Optical Properties of Ultra-Thin Crystals(John Wiley and Sons Inc., 2016) Şahin, Hasan; Torun, Engin; Bacaksız, Cihan; Horzum, Şeyda; Kang, J.; Senger, Ramazan Tuğrul; Peeters, François M.An overview is given of recent advances in experimental and theoretical understanding of optical properties of ultra-thin crystal structures (graphene, phosphorene, silicene, MoS2 , MoSe2 , WS2 , WSe2 , h-AlN, h-BN, fluorographene, and graphane). Ultra-thin crystals are atomically thick-layered crystals that have unique properties which differ from their 3D counterpart. Because of the difficulties in the synthesis of few-atom-thick crystal structures, which are thought to be the main building blocks of future nanotechnology, reliable theoretical predictions of their electronic, vibrational, and optical properties are of great importance. Recent studies revealed the reliable predictive power of existing theoretical approaches based on density functional theory.Article Citation - WoS: 22Citation - Scopus: 22Electronic and Magnetic Properties of 1t-Tise2 Nanoribbons(IOP Publishing Ltd., 2015) Özaydın, H. Duygu; Şahin, Hasan; Kang, J.; Peeters, François M.; Şenger, Ramazan TuğrulMotivated by the recent synthesis of single layer TiSe2,we used state-of-the-art density functional theory calculations, to investigate the structural and electronic properties of zigzag and armchairedged nanoribbons (NRs) of this material. Our analysis reveals that, differing from ribbons of other ultra-thin materials such as graphene, TiSe2 NRs have some distinctive properties. The electronic band gap of the NRs decreases exponentially with the width and vanishes for ribbons wider than 20 Å. For ultranarrow zigzag-edged NRs we find odd-even oscillations in the band gap width, although their band structures show similar features. Moreover, our detailed magnetic-ground-state analysis reveals that zigzag and arm chair edged ribbons have non-magnetic ground states. Passivating the dangling bonds with hydrogen at the edges of the structures influences the band dispersion. Our results shed light on the characteristic properties of T phase NRs of similar crystal structures.