Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
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Article Citation - WoS: 4Citation - Scopus: 4Anisotropic Single-Layer Tilted Α-Bi: Identification of Uniaxial Strain Via Raman Spectrum(Amer Chemical Soc, 2024) Dogan, Kadir Can; Yagmurcukardes, MehmetIn the present study, the structural, vibrational, electronic, and elastic properties of single-layer alpha-Bi are investigated by performing density functional theory-based first-principles calculations. Structural optimizations show that free-standing alpha-Bi possesses a tilted black phosphorus-like anisotropic structure. The phonon band dispersions and linear-elastic parameters reveal the dynamical and mechanical stability of the alpha-Bi structure, respectively. In addition, quantum molecular dynamics simulations indicate the thermal stability of the single layer at room temperature. Electronically, it is found that alpha-Bi exhibits an indirect band gap semiconducting behavior, whose hole and electron effective masses are shown to be orientation-dependent with the latter being more anisotropic. Such anisotropic effective masses reveal orientation-dependent transport properties in single-layer alpha-Bi. Moreover, the orientation-dependent elastic features of alpha-Bi show that at an angle of 45 degrees with respect to the zigzag (ZZ) orientation, an auxetic behavior is predicted for the structure. Furthermore, the impact of uniaxial strains along the two main orientations (ZZ and armchair directions) is investigated on the vibrational properties of single-layer alpha-Bi. The phononic stability of the structure is first predicted at the strain limits (+/- 5) for both directions, and the results reveal the preserved stability of the single layer under both compressive and tensile strains. The calculated Raman spectra under uniaxial strains show that the type (compressive or tensile) and the direction of the applied strain can be deduced from the Raman spectra analysis. Overall, strain-induced modifications in the Raman spectrum of 2D alpha-Bi in terms of the peak positions may be useful tools for the characterization of induced strain in experimental studies.Article Citation - WoS: 1Anisotropic Structural, Vibrational, Electronic, Optical, and Elastic Properties of Single-Layer Hafnium Pentatelluride: an <i>ab Initio</I> Study(Royal Soc Chemistry, 2024) Dogan, Kadir Can; Cetin, Zebih; Yagmurcukardes, MehmetMotivated by the highly anisotropic nature of bulk hafnium pentatelluride (HfTe<INF>5</INF>), the structural, vibrational, electronic, optical, and elastic properties of single-layer two-dimensional (2D) HfTe<INF>5</INF> were investigated by performing density functional theory (DFT)-based first-principles calculations. Total energy and geometry optimizations reveal that the 2D single-layer form of HfTe<INF>5</INF> exhibits in-plane anisotropy. The phonon band structure shows dynamic stability of the free-standing layer and the predicted Raman spectrum displays seven characteristic Raman-active phonon peaks. In addition to its dynamic stability, HfTe<INF>5</INF> is shown to exhibit thermal stability at room temperature, as confirmed by quantum molecular dynamics simulations. Moreover, the obtained elastic stiffness tensor elements indicate the mechanical stability of HfTe<INF>5</INF> with its orientation-dependent soft nature. The electronic band structure calculations show the indirect-gap semiconducting behavior of HfTe<INF>5</INF> with a narrow electronic band gap energy. The optical properties of HfTe<INF>5</INF>, in terms of its imaginary dielectric function, absorption coefficient, reflectance, and transmittance, are shown to exhibit strong in-plane anisotropy. Furthermore, structural analysis of several point defects and their oxidized structures was performed by means of simulated STM images. Among the considered vacancy defects, namely , , V<INF>Te<INF>out</INF></INF>, V<INF>Te<INF>in</INF></INF>, , and V<INF>Hf</INF>, the formation of V<INF>Te<INF>out</INF></INF> is revealed to be the most favorable defect. While and V<INF>Hf</INF> defects lead to local magnetism, only the oxygen-substituted V<INF>Hf</INF> structure possesses magnetism among the oxidized defects. Moreover, it is found that all the bare and oxidized vacant sites can be distinguished from each other through the STM images. Overall, our study indicates not only the fundamental anisotropic features of single-layer HfTe<INF>5</INF>, but also shows the signatures of feasible point defects and their oxidized structures, which may be useful for future experiments on 2D HfTe<INF>5</INF>.Correction Chlorinated Phosphorene for Energy Application (vol 231, 112625, 2024)(Elsevier, 2024) Hassani, Nasim; Yagmurcukardes, Mehmet; Peeters, Francois M.; Neek-Amal, Mehdi[No Abstract Available]Correction Chlorinated Phosphorene for Energy Application (vol 231, 112625, 2024)(Elsevier, 2024) Hassani, Nasim; Yagmurcukardes, Mehmet; Peeters, Francois M.; Neek-Amal, Mehdi[No Abstract Available]