2- ENSTİTÜLER
http://hdl.handle.net/123456789/52
2017-09-20T12:43:40ZBand Structure and Optical Properties of BiOCl: Density Functional Calculation
http://hdl.handle.net/123456789/468
Band Structure and Optical Properties of BiOCl: Density Functional Calculation
Koc, Hüsnü, Harun and Amirullah M. Akkuş and Mamedov
The electronic band structures, density of states (DOS) and optical properties of BiOCl Crystal are investigated using the density functional theory under the local density approximation (LDA). The obtained electronic band structure show that BiOCl crystal has an indirect forbidden band gap of 2.45 eV. The structural optimization for BiOCl has been performed using the LDA. The result of the structure optimization of BiOCl have been
compared with the experimental results and have been found to be in good agreement with these results. 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.
2014-02-27T00:00:00ZMechanical, electronic, and optical properties of Bi2S3 and Bi2Se3 compounds: first principle investigations
http://hdl.handle.net/123456789/467
Mechanical, electronic, and optical properties of Bi2S3 and Bi2Se3 compounds: first principle investigations
Koc, Ozisik, Deligoz, Mamedov, and Ozbay
The 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, nisotropy 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 nonlinearities for Bi2S3 and Bi2Se3 (tensors of elasto-optical coefficients) under pressure.
2014-03-16T00:00:00ZElectron Spectroscopy and The Electronic Structure of KNbO3: First Principle Calculations
http://hdl.handle.net/123456789/466
Electron Spectroscopy and The Electronic Structure of KNbO3: First Principle Calculations
Simsek, Şevket, Hüsnü, V.A, Amirullah M. and Ekmel Koc, Terepakov, Mamedov, and Ozbay
The electronic structures of KNbO3 were calculated within the density functional theory,
and their evolution was analyzed as the crystal-field symmetry changes from cubic to
rhombohedral via tetragonal phase. We carried out electron-energy loss spectroscopy
experiments by using synchrotron radiation and compared the results with the theoretical
spectra calculated within Density Functional Theory. The dominant role of the NbO6
octahedra in the formation of the energy spectra of KNbO3 compound was demonstrated.
The anomalous behavior of plasmons in ferroelectrics was exhibited by the function
representing the characteristic energy loss in the region of phase transition.
2014-05-01T00:00:00ZFirst principles prediction of the elastic, electronic, and optical properties of Sb2S3 and Sb2Se3 compounds
http://hdl.handle.net/123456789/465
First principles prediction of the elastic, electronic, and optical properties of Sb2S3 and Sb2Se3 compounds
Koc, Ozisik, Deligoz, Mamedov, and Ozbay
We have performed a first principles study of structural, mechanical, electronic, and optical properties of orthorhombic Sb2S3 and Sb2Se3 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 photonenergy 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. Ourstructural estimation and some other results are in agreement with the available experimental and theoretical data.
2012-06-06T00:00:00Z