The Structural, Electronic, Elastic and Dynamic Properties of Co3W in the L1(2) Phase

32nd International Physics Congress of Turkish-Physical-Society (TPS) -- SEP 06-09, 2016 -- Bodrum, TURKEYWOS: 000435205100035A theoretical study is presented for the structural, electronic, elastic and phonon properties of Co3W compounds in L1(2) phase in the framework of density functional theory. The calculations are carried out within the PBE-GGA for the exchange correlation potential. The electronic structure and particle density of states (DOS) show that Co3W compound is metallic with sturdy hybridization near the Fermi level. The phonon dispersion curves, and the projected density of states been investigated for the first time with an alpha b initio method using density functional perturbation theory (DFPT). Temperature variations of specific heat capacity in the range of 0-2000 K are obtained using the quasi-harmonic model.Turkish Phys SocAhi Evran University Research Project UnitAhi Evran University [EGT.E2.16.016]This work was supported by the Ahi Evran University Research Project Unit under Project no. EGT.E2.16.016

The first-principles study on Zr3Al and Sc3Al in L1(2) structure

WOS: 000316429000025The elastic, electronic, and phonon properties of the intermetallic compounds Zr3Al and Sc3Al in the L1(2) structure have been investigated in detail by employing an ab initio pseudopotential method and a linear-response technique within a generalized gradient approximation (GGA) of the density-functional theory (OFT) scheme. The calculated ground-state properties such as lattice constants and bulk modulus agree well with the previous theoretical calculations. The numerical first-principles calculations of the elastic constants have been used to calculate C-11, C-12, and C-44 for Zr3Al and Sc3Al. The electronic band structures of Zr3Al and Sc3Al show that at the Fermi level, a major part of the contribution comes from Zr 4d (Sc 3d) states. The phonon-dispersion curves and phonon total and partial density of states based on the linear-response method have been investigated for both materials. Temperature variations of specific heat capacity in the range of 0-500 K are obtained using the quasi-harmonic model. (C) 2013 Elsevier Ltd. All rights reserved.Ahi Evran University Research Project UnitAhi Evran University [FBA-11-29]This work was supported by the Ahi Evran University Research Project Unit under Project no. FBA-11-29

Ab initio calculation of structural, electronic and phonon properties of ZrRu and ZrZn in B2 phase

WOS: 000293030100022The structural, electronic and dynamic properties of cesium chloride, ZrRu and ZrZn were studied by employing an ab initio pseudopotential method and a linear response scheme, within the generalized gradient approximation. The calculated lattice constant, bulk modulus and first-order pressure derivative of the bulk modulus were reported in B2 structure and compared with available experimental and other theoretical results. The electronic band structure, partial and total density of states were determined by using the Quantum-Espresso ab initio simulation package based on pseudopotential method. Phonon dispersion curves and density of states were calculated by employing a density functional perturbation theory. (C) 2011 Elsevier B.V. All rights reserved

Structural, electronic, elastic, thermodynamic and phonon properties of LaX (X = Cd, Hg and Zn) compounds in the B2 phase

WOS: 000385424200006The ab initio computations have been performed to examine the structural, elastic, electronic and phonon properties of cubic LaX (X = Cd, Hg and Zn) compounds in the B2 phase. The optimized lattice constants, bulk modulus, and its pressure derivative and elastic constants are evaluated and compared with available data. Electronic band structures and total and partial densities of states (DOS) have been derived for LaX (X = Cd, Hg and Zn) compounds. The electronic band structures show metallic character; the conductivity is mostly governed by La-5d states for three compounds. Phonon-dispersion curves have been obtained using the first-principle linear-response approach of the density-functional perturbation theory. The specific heat capacity at a constant volume C-V of LaX (X = Cd, Hg and Zn) compounds are calculated and discussed

First-principles study of electronic and dynamic properties of AgMg and AgZn

WOS: 000303622200016The structural, electronic, and phonon properties of AgMg and AgZn in the cesium-chloride phase have been investigated using the density functional theory (DFT) within the local density approximation (LDA). The calculated ground state properties such as lattice constant and bulk modulus agree well with the previous theoretical calculations. The electronic band structure is also presented for AgMg and AgZn. The calculated DOS at the Fermi energy are 0.49states/eV cell for AgMg and 0.43states/eV cell for AgZn. A linear-response approach to the density functional theory is used to derive phonon dispersion curves and the total and partial density of states for AgMg and AgZn. The high-frequency region of AgMg is mainly due to the vibrations of Mg atoms. (C) 2012 Elsevier Ltd. All rights reserved

Electronic and phonon properties of Sc-TM (TM = Ag, Cu, Pd, Rh, Ru) compounds

WOS: 000274222000007A theoretical study of structural, electronic and phonon properties of the Sc-TM (TM = Ag, Cu, Pd, Rh, Ru) in the B2 phase was presented using the density functional theory within the generalized gradient approximation (GGA). The ground state quantities such as lattice parameter, bulk modulus and first-order pressure derivative of the bulk modulus, were evaluated. The calculated structural and electronic properties were in good agreement with previous theoretical and experimental results. The calculated total density of states showed that they were all metallic. Phonon-dispersion curves were obtained using the first principles linear-response approach of the density functional perturbation theory (DFPT). (C) 2009 Elsevier B.V. All rights reserved.Gazi UniversityGazi University [05/2009-39]This work was supported by the Gazi University Research Project Unit under Project No. 05/2009-39

The structural, electronic and dynamic properties of the L12- type Co3Ti alloy

International Conference of Computational Methods in Sciences and Engineering 2014 (ICCMSE) -- APR 04-07, 2014 -- Athens, GREECEWOS: 000346015200042The structural, electronic and dynamic properties of the cubic Co3Ti alloy in L1(2) structure have been investigated using a pseudopotential plane wave (PP-PW) method within the generalized gradient approximation proposed by Perdew-Burke-Ernzerhof (GGA-PBE). The structural properties, including the lattice constant, the bulk modulus and its pressure derivative agree reasonably with the previous results. The density of state (DOS), projected density of state (PDOS) and electronic band structure are also reported. The DOS shows that Co3Ti alloy has a metallic character since the energy bands cross the Fermi level. The density of states at Fermi level mainly comes from the Co-3d states. Phonon dispersion curves and their corresponding total densities of states were obtained using a linear response in the framework of the density functional perturbation theory. All computed phonon frequencies are no imaginer and thus, Co3Ti alloy is dynamically stable. The zone center phonon modes have been founded to be 9.307, 9.626 and 13.891 THz for Co3Ti.European Soc Computat Methods Sci Engn & TechnolAhi Evran University Research [YO-J.4010 14.001]This work was supported by Ahi Evran University Research Project Unit under YO-J.4010 14.001

Investigations of Structural, Elastic, Electronic and Thermodynamic Properties of X2TiAl Alloys: A Computational Study

WOS: 000443274900009First-principle calculations have been adopted in order to reveal and deeply understand the structural, electronic, elastic, thermodynamic, and vibrational properties of full-Heusler X2TiAl (X = Au, Ru, and Zr) alloys in the L2(1) phase. The fundamental physical properties such as bulk modulus, its pressure derivative, anisotropy factor, shear modulus, Poisson's ratio, Cauchy pressure, elastic constants, heat capacity, thermal expansion coefficient, and Young's modulus are obtained and compared with the literature. Debye temperature and Gruneisen parameter are also evaluated over the temperature range of 0-1500 K. Electronic band structures and their partial density of states and phonon dispersion curves are presented for all alloys and used to interpret the electronic and mechanical properties and stabilities of alloys in the L2(1) phase

Mechanical and dynamical properties of Co3Al and Co3Ta alloys in L1(2) phase

WOS: 000403942800008The structural, elastic, electronic and vibrational properties of Co3Al and Co3Ta alloys with density functional theory have been investigated. The lattice constants, bulk modulus and its pressure derivative are evaluated and compared with the available data. The numerical first principles calculations of the elastic constants were used to calculate C-11, C-12 and C-44 for Co3Al and Co3Ta alloys. The electronic band structure, electronic total and partial densities of states, and total magnetic moment of the Co3Al and Co3Ta alloys are computed and analyzed in comparison with the existing findings. From the electronic calculations made for both alloys, it was found that the alloys were metallic in nature. Phonon-dispersion curves and their corresponding total and projected densities of states have been obtained for the first time using a linear-response in the framework of the density functional perturbation theory. The frequencies of the optical phonon modes of both alloys are calculated and found to be 4.46, 6.095 and 10.35 THz for Co3Al, 4.83, 6.11 and 6.86 THz for Co3Ta. Finally, specific heat capacity at a constant volume versus temperature CV of Co3Al and Co3Ta alloys is calculated and discussed using the quasi harmonic approximation

A Soft Computing Based Approach Using Modified Selection Strategy for Feature Reduction of Medical Systems

The systems consisting high input spaces require high processing times and memory usage. Most of the attribute selection algorithms have the problems of input dimensions limits and information storage problems. These problems are eliminated by means of developed feature reduction software using new modified selection mechanism with middle region solution candidates adding. The hybrid system software is constructed for reducing the input attributes of the systems with large number of input variables. The designed software also supports the roulette wheel selection mechanism. Linear order crossover is used as the recombination operator. In the genetic algorithm based soft computing methods, locking to the local solutions is also a problem which is eliminated by using developed software. Faster and effective results are obtained in the test procedures. Twelve input variables of the urological system have been reduced to the reducts (reduced input attributes) with seven, six, and five elements. It can be seen from the obtained results that the developed software with modified selection has the advantages in the fields of memory allocation, execution time, classification accuracy, sensitivity, and specificity values when compared with the other reduction algorithms by using the urological test data