Browsing by Author "Ozisik, H."
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Item Open Access Mechanical, electronic, and optical properties of Bi2S3 and Bi2Se3 compounds: first principle investigations(Springer Berlin Heidelberg, 2014) Koc, H.; Ozisik, H.; Deligoz, E.; Mamedov, A. M.; Özbay, EkmelThe structural, mechanical, electronic, and optical properties of orthorhombic Bi2S3 and Bi2Se3 compounds have been investigated by means of first principles calculations. The calculated lattice parameters and internal coordinates are in very good agreement with the experimental findings. The elastic constants are obtained, then the secondary results such as bulk modulus, shear modulus, Young's modulus, Poisson's ratio, anisotropy factor, and Debye temperature of polycrystalline aggregates are derived, and the relevant mechanical properties are also discussed. Furthermore, the band structures and optical properties such as real and imaginary parts of dielectric functions, energy-loss function, the effective number of valance electrons, and the effective optical dielectric constant have been computed. We also calculated some non-linearities for Bi2S3 and Bi2Se3 (tensors of elasto-optical coefficients) under pressureItem Open Access Optical and electronic properties of orthorhombic and trigonal AXO3 (A=Cd, Zn; X=Sn, Ge): first principle calculation(Taylor and Francis Inc., 2016) Ozisik, H.; Simsek S.; Deligoz, E.; Mamedov, A. M.; Özbay, EkmelElectronic structure and optical properties of the CdXO3 and ZnXO3 (X˭Ge, Sn) compounds have been investigated based on density functional theory. According to the predictive results, reveal that the CdXO3 and ZnXO3 would be candidates for a high performance lead free optical crystal, which will avoid the environmental toxicity problem of the lead-based materials.Item Open Access Optical and magnetic properties of some XMnSb and Co2YZ compounds: ab initio calculations(Wiley-VCH Verlag, 2017) Palaz S.; Koc, H.; Ozisik, H.; Deligoz, E.; Mamedov, A. M.; Özbay, EkmelIn present work, our research is mainly focused on the electronic structures, optical, and magnetic properties of XMnSb (X = Ni, Cu, Pd), Co2YZ (Y = Ti; Z=Si, Ge, Sn), and Co2YZ (Y =Mn; Z=Al, Ga, Si) Heusler compounds by using ab initio calculations within the generalized gradient approximation. The calculations are performed by using the Vienna ab initio simulation package based on the density functional theory. The band structure of these Heusler alloys for majority spin and minority spin were calculated and the majority spin states cross the Fermi level and thus have the metallic character, while the minority spin states open the band gaps around the Fermi level and thus have the narrow-band semiconducting nature. We also find that these Heusler compounds have the indirect band gaps in the minority spin channel. The real and imaginary parts of dielectric functions and hence the optical functions such as energy-loss function, the effective number of valance electrons and the effective optical dielectric constant for XMnSb and Co2YZ compounds were also calculated. In addition, we also show the variations of the total magnetic moment per f.u. and minority spin gap width of these compounds with optimized lattice constants: minority spin gap width decreases with increasing the lattice constants. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim