Browsing by Subject "Structural estimation"

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    First principles prediction of the elastic, electronic, and optical properties of Sb 2S 3 and Sb 2Se 3 compounds
    (2012) Koc H.; Mamedov, A.M.; Deligoz, E.; Ozisik H.
    We have performed a first principles study of structural, mechanical, electronic, and optical properties of orthorhombic Sb 2S 3 and Sb 2Se 3 compounds using the density functional theory within the local density approximation. The lattice parameters, bulk modulus, and its pressure derivatives of these compounds have been obtained. The second-order elastic constants have been calculated, and the other related quantities such as the Young's modulus, shear modulus, Poisson's ratio, anisotropy factor, sound velocities, Debye temperature, and hardness have also been estimated in the present work. The linear photon-energy dependent dielectric functions and some optical properties such as the energy-loss function, the effective number of valence electrons and the effective optical dielectric constant are calculated. Our structural estimation and some other results are in agreement with the available experimental and theoretical data. © 2012 Elsevier Masson SAS. All rights reserved.
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    Optical properties of the narrow-band ferroelectrics: first principle calculations
    (Taylor & Francis Inc., 2015) Koc, H.; Simsek S.; Mamedov, A. M.; Özbay, Ekmel
    Based on density functional theory, we have studied the electronic, and optical properties of narrow-band ferroelectric compounds - (Ge,Sn) Te. Generalized gradient approximation has been used for modeling exchange-correlation effects. The lattice parameters of the considered compounds have been calculated. The calculated electronic band structure shows that GeTe and SnTe compounds have a direct forbidden band gap of 0.742 and 0.359. The real and imaginary parts of dielectric functions and therefore, the optical functions such as energy-loss function, as well as the effective number of valance electrons and the effective optical dielectric constant are all calculated. Our structural estimation and some other results are in agreement with the available experimental and theoretical data. © 2015 Taylor & Francis Group, LLC.
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    Structural, elastic, and electronic properties of topological insulators: Sb2Te3 and Bi2Te3
    (IEEE, 2013) Koc H.; Mamedov, Amirullah M.; Özbay, Ekmel
    We have performed a first principles study of structural, elastic, and electronic properties of rhombohedral Sb2Te3 and Bi 2Te3 compounds using the density functional theory within the local density approximation. The lattice parameters of considered compounds have been calculated. The second-order elastic constants have been calculated, and the other related quantities such as the Young's modulus, shear modulus, Poisson's ratio, anisotropy factor, sound velocities, and Debye temperature have also been estimated in the present work. The calculated electronic band structure shows that Sb2Te3 and Bi2Te 3 compounds have a direct forbidden band gap. Our structural estimation and some other results are in agreement with the available experimental and theoretical data. © 2013 IEEE.