Browsing by Author "Erdinc, Bahattin"

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Ab Initio Calculation of Physical Properties of Sodium Chloride
(Amer Scientific Publishers, 2013) Dogan, Emel Kilit; Secuk, Nurullah; Erdinc, Bahattin; Soyalp, Fethi; Akkus, Harun
We have calculated the structural, electronic, optical, dynamical, and thermodynamical properties of sodium chloride crystal using the density functional theory within the generalized gradient approximation. The calculated results for each physical property are presented and compared with available experimental data and previous theoretical data. There are controversial reports in the literature on the electronic band structure of sodium chloride. We especially present data and comments about this controversial subject.
Ab-Initio Calculations of Physical Properties of Alkali Chloride Xcl (X = K, Rb and Li) Under Pressure
(Elsevier, 2015) Erdinc, Bahattin; Secuk, Mehmet Nurullah; Aycibin, Murat; Gulebagan, Sinem Erden; Dogan, Emel Kilit; Akkus, Harun
Structural properties, electronic band structure, real and imaginary parts of complex dielectric function of alkali chloride XCl (K, Rb and Li) compounds were investigated under various pressures using first principles calculations. Moreover, Gibbs free energies were also calculated at those pressures. Calculated results of the Gibbs free energy show that LiCl does not show any structural phase transition. However, structural phase transitions of KCl and RbCl occur from NaCl (B1) to CsCl (B2) at 4.5 and 1.7 GPa pressures, respectively. The electronic band gaps under pressure were also calculated. The calculated physical properties of these compounds are compared with the previous theoretical and experimental results and a good agreement was observed. (c) 2015 The Authors. Published by Elsevier B. V. This is an open access article under the CC BY-NC-ND license.
Ab-Initio Study of Csgecl3 Compound in Paraelectric and Ferroelectric Phases
(Taylor & Francis Ltd, 2016) Erdinc, Bahattin; Secuk, Mehmet Nurullah; Aycibin, Murat; Gulebagan, Sinem Erden; Dogan, Emel Kilit; Akkus, Harun
Structural optimization, electronic energy band structure, density of states, optical, lattice dynamic and thermodynamic properties of CsGeCl3 compound in paraelectric and ferroelectric phases were investigated using the DFT in the GGA and LDA approximations. The obtained results of CsGeCl3 crystal were compared with the available theoretical and experimental results and have been found to be in good agreement with these results.
Ab-Initio Study of the Electronic Structure and Optical Properties of Kno3 in the Ferroelectric Phase
(Iop Publishing Ltd, 2009) Erdinc, Bahattin; Akkus, Harun
The electronic band structure and optical properties of the ferroelectric phase III of KNO3 have been investigated by the first-principle pseudopotential method using the density functional theory under the generalized gradient approximation (GGA) and local density approximation (LDA). The calculated band structure shows that the ferroelectric phase III of KNO3 has a direct band gap with a value of 1.76 eV at the point of the first Brillouin zone (BZ). The structural optimization of KNO3 has been performed using the GGA and LDA. The results of the structure optimization have been compared with the experimental results and have been found to be in good agreement with these results. Moreover, the linear photon-energy-dependent dielectric functions and some optical constants such as energy-loss functions for volume and surface, extinction, reflectivity and absorption coefficients, refractive index and effective number of valance electrons per unit cell participating in the interband transitions have been calculated.
Calculation of Electronic Band Structure of Ferroelectric Semiconductor Bismuth Niobium Oxyfluoride (Bi2nbo5f) Crystal
(Gazi Univ, 2014) Erdinc, Bahattin; McCabe, Emma; Duran, Duygu; Secuk, M. Nurullah; Gulebaglan, Sinem Erden; Dogan, Emel Kilit; Akkus, Harun
In this study, the geometric structural optimization, electronic band structure and density of states ( DOS) for electrons of ferroelectric Bi2NbO5F structure with space group Pca21 have been investigated using the density functional theory (DFT) under the local density approximation (LDA). The ground state properties of ferroelectric Bi2NbO5F structure are studied. The computed ground state properties and experimental results are consistent. The energy band structure of Bi2NbO5F compound below T-c shows that it is a ferroelectric semiconductor with narrow band gap of 0.0589 eV. Unfortunately, there is neither experimental nor theoretical electronic band structure study of Bi2NbO5F crystal in the literature, so we could not compare our results.
Density Functional Calculations of the Electronic Band Structure and Optical Properties of Kcaf3
(Gazi Univ, 2011) Erdinc, Bahattin
The electronic band structure and optical properties of cubic KCaF3 are studied using the density functional theory. The calculated band structure of cubic KCaF3 shows an indirect band gap with two values of 5.95 eV and 5.94 eV at the M -> Gamma and Gamma -> R lines of Brillouin zone, respectively. The structural optimization has been performed using the generalized gradient approximation (GGA). The calculated structure optimization of KCaF3 has been compared with experimental results. Good agreement between theoretical and experimental results was observed. Moreover, some optical constants such as energy-loss functions for volume and surface, coefficients of extinction, reflectivity and absorption, refractive index and effective number of valence electrons per unit cell participating in the inter-band transitions and the linear photon-energy-dependent dielectric functions have been calculated.
Dft Study of Cscaf3: Eu
(Gazi Univ, 2016) Aycibin, Murat; Erdinc, Bahattin
In this article, we studied some changes on structural, optical and electronic properties of CsCaF3 when it is doped with Eu atom. All properties of doped CsCaF3 are calculated using the full potential linearized augmented plane wave to the density functional theory. The exchange-correlation potential is evaluated using generalized gradient approximation. This work presents comparison of undoped and doped with Eu atoms of CsCaF3 compound. Moreover, we show that CsCaF3: Eu has indirect band gap with the Generalized Gradient Approximation and doping makes energy band gap values decreases.
Electronic and Optical Properties of Gas: a First-Principles Study
(Gazi Univ, 2010) Erdinc, Bahattin; Akkus, Harun; Goksen, Kadir
The electronic band structure and optical properties of hexagonal GaS are investigated using the density functional theory. The calculated band structure shows that the crystal has an indirect band gap with the value of 1.54 eV in the Brillouin zone at the Gamma -> M. The structural optimization has been performed using the generalized gradient approximation (GGA) and the local density approximation (LDA). The calculated structure optimization of GaS has been compared with the experimental results and has been found to be in good agreement with each other. Furthermore, the linear photon-energy-dependent dielectric functions and some optical constants such as energy-loss functions for volume and surface, extinction, reflectivity and absorption coefficients, refractive index and effective number of valence electrons per unit cell participating in the interband transitions have been calculated.
Electronic and Optical Properties of Γ-Ag3si by Using First Principles
(Korean Physical Soc, 2010) Erdinc, Bahattin; Akkus, Harun
The electronic energy band structure and the optical properties of gamma-Ag3SI are calculated by using density functional theory under the local density approximation (LDA). The calculated electronic band structure shows that gamma-Ag3SI has an indirect gap with a value of 0.46 eV at the M -> Gamma points in the Brillouin zone. A structural optimization has been performed by using the LDA. The optical spectra of the gamma-Ag3SI in the photon range up to 30 eV are calculated by using a first-principles method under the scissor approximation. The real and the imaginary parts of the dielectric function as functions of the photon energy and, thus, the optical constants, such as the energy-loss function, the refractive index, and the effective number of electrons, are investigated. The calculated structural optimization of gamma-Ag3SI is compared with the experimental results and is found to be in good agreement with the experimental data.
Electronic Band Structure and Linear Optical Properties of Paraelectric Kio3
(Iop Publishing Ltd, 2009) Erdinc, Bahattin; Akkus, Harun
The electronic energy band structure, partial (PDOS) and total density of states (DOS), and linear optical properties of the paraelectric KIO3 single crystal are calculated using density functional theory (DFT) in its local density approximation (LDA). The calculated band structure for paraelectric KIO3 indicates that the crystal has a direct bandgap. Using LDA and generalized gradient approximation (GGA), structural optimization has been performed. The optical spectra of the paraelectric KIO3 in the photon energy range up to 30 eV are investigated under the scissor approximation. The real and imaginary parts of the frequency-dependent linear dielectric function, as well as related quantities such as energy-loss function, refractive index and effective number of valence electrons, are calculated. The calculated structural optimization and bandgap of the paraelectric KIO3 have been compared with experimental data and have been found to be in good agreement with the experimental results.
Electronic Structure and Lattice Dynamics of Baceo3 Compound in Cubic Phase
(Springer, 2014) Aycibin, Murat; Erdinc, Bahattin; Akkus, Harun
In this paper, electronic band structure, total density of states, and optical, lattice dynamic and thermo-dynamic properties of BaCeO3 compound in cubic phase were investigated using density functional theory within the generalized gradient approximation. The calculated lattice constant is consistent with the experimental result. In cubic phase, BaCeO3 has a semiconductor character with 2.17 eV band gap.
First-Principles Investigation of Structural, Electronic, Optical and Dynamical Properties in Csau
(de Gruyter Open Ltd, 2011) Erdinc, Bahattin; Soyalp, Fethi; Akkus, Harun
The structural, electronic, optical and dynamical properties of CsAu compound in the CsCl(B2) phase were investigated using the density functional theory (DFT) within the generalized gradient approximation (GGA). The calculated lattice constant, static bulk modulus and first-order pressure derivative of the bulk modulus are reported and compared with previous experimental and theoretical calculations. The calculated electronic band structure for this compound is in good agreement with available theoretical and experimental studies. The present band calculation indicates that CsAu compound has an indirect gap at R -> X points. Furthermore, the linear photon-energy-dependent dielectric functions have been calculated. For the first time, the electronic structure results are used, within the implementation of a linear-response technique, for calculations of phonon properties.
First-Principles Study of Electronic and Optical Properties of Cubic Agtao3 Structure in Paraelectric Phase at Different Pressures
(Taylor & Francis Ltd, 2016) Erdinc, Bahattin; Dede, Melike
In the present article, a theoretical study of structural properties, energy band structure, total (TDOS) and partial (PDOS) density of states, real and imaginary parts of photon frequency dependent complex dielectric function of cubic AgTaO3 in paraelectric phase was presented by ab-initio calculations using DFT-LDA in the ABINIT code. The obtained energy band structure under various pressures shows that AgTaO3 has an indirect band gap at the Gamma and M points in the first Brillouin zone which increases by increasing pressure. Calculated results for energy band gap and optical properties under pressure are given and these results were compared with the experimental results and previous calculations.
First-Principles Study of Nacdf3
(Wiley-v C H verlag Gmbh, 2009) Akkus, Harun; Erdinc, Bahattin
The electronic structure, density of states and linear optical properties of NaCdF3 are studied using density functional methods in the local density approximation (LDA) and the generalized gradient approximation (GGA). The calculated band structure of NaCdF3, shows a direct band gap at the Gamma-point in the Brillouin zone. The structural optimization of NaCdF3 is performed using the LDA and the GGA. The calculated structural optimization of NaCdF3 is compared with previous results and is found to be in good-agreement with those results. The optical spectra of NaCdF3 in the photon energy range up to 30 eV are investigated under the scissor approximation. The real and imaginary parts of the dielectric function as a function of the photon energy and hence optical constants Such as refractive index, energy loss for volume and surface, extinction coefficient, reflectivity and absorption coefficient have been calculated. (c) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Linear Optical Properties of Ferroelectric Semiconductor Bi2nbo5f Crystal
(Taylor & Francis Ltd, 2015) Duran, Duygu; Erdinc, Bahattin; Aycibin, Murat; Akkus, Harun
In this paper, we investigated the electronic band structure, total and partial density of states and optical properties of ferroelectric Bi2NbO5F structure with space group Pca2(1) using the density functional theory under the generalized gradient approximation. Our computational results show that Bi2NbO5F compound is a ferroelectric semiconductor with a narrow band gap. Due to anisotropy, linear optical properties of component were calculated for three crystallographic directions.
Physical Properties of Rbau Compound
(Elsevier Science Bv, 2014) Aycibin, Murat; Dogan, Emel Kilit; Gulebaglan, Sinem E.; Secuk, M. Nurullah; Erdinc, Bahattin; Akkus, Harun
In this paper, we investigated electronic, optic, elastic, dynamic and thermodynamic properties of RbAu compound by density functional theory within the generalized gradient approximation. The calculated static value of real part of dielectric constant is 6.7. The calculated electronic band structure of RbAu shows that RbAu is a semiconductor with an indirect band gap of 0.36 eV. Besides, RbAu obeys mechanical stability and it demonstrates elastic anisotropy. 540K is classical limit for specific heat of RbAu. (C) 2014 The Authors. Published by Elsevier B.V.
Structural and Electronic Properties of Zincblende Phase of Tl X Ga1-X as Y P1-Y Quaternary Alloys: First-Principles Study
(Sciendo, 2013) Gulebaglan, Sinem E.; Dogan, Emel K.; Aycibin, Murat; Secuk, Mehmet N.; Erdinc, Bahattin; Akkus, Harun
Using the first-principles band-structure method, we have calculated the structural and electronic properties of zincblende TlAs, TlP, GaAs and GaP compounds and their new semiconductor Tl (x) Ga1-x As (y) P1-y quaternary alloys. Structural properties of these semiconductors are obtained with the Perdew and Wang local-density approximation. The lattice constants of Tl (x) Ga1-x As, Tl (x) Ga1-x P ternary and Tl (x) Ga1-x As (y) P1-y quaternary alloys were composed by Vegard's law. Our investigation on the effect of the doping (Thallium and Arsenic) on lattice constants and band gap shows a non-linear dependence for Tl (x) Ga1-x As (y) P1-y quaternary alloys. The band gap of Tl (x) Ga1-x As (y) P1-y , E (g) (x, y) concerned by the compositions x and y. To our awareness, there is no theoretical survey on Tl (x) Ga1-x As (y) P1-y quaternary alloys and needs experimental verification.