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Öğe Ab-initio calculations of structural, electronic, and magnetic properties of Li based heusler compounds(Nova Science Publishers, Inc., 2024) Balci, Gulten Kavak; Ayhan, SeyfettinIn today's technology, the basic properties of these materials must be known to benefit from the material that is produced artificially or exists naturally. The material properties of atoms or molecules can be calculated both experimentally and theoretically. Every new research contributes to improving data and new methods that cost less. Schrodinger equation of the structure of atoms and molecules needs to be resolved to determine the physical properties of these systems. However, for a small number of systems it can be analytically solved and for a few systems numerical solutions can be made. In addition, the Schrodinger equation's analytical or numerical solution is not possible for a many-body system because of electron-electron and electron-core interaction. Therefore, some methods are used to analyze the many-body systems. These methods can be listed as the Wave Functions method, Green's Functions method, and density functional theory (DFT). Here, we will focus on the development of density functional theory. The calculation of the electronic structure of crystal structures is made using computer software packaged programs such as ABINIT, SIESTA, VASP, and Wien2k, which are based on Kohn-Sham equations and Ab-initio methods that enable exact solutions of quantum mechanical ground states of electron systems. In this study, the structural, electronic, and magnetic properties of Libased structures will be determined using the density functional theorybased package program called the Wien2k. © 2024 Nova Science Publishers, Inc. All rights reserved.Öğe Ab-initio calculations: structural, electronic and elastic properties of LiX2Ge (X: Rh, Cu, Ni, Pd) Heusler compounds(Iop Publishing Ltd, 2019) Ayhan, Seyfettin; Balci, Gulten KavakIn this study, the structural, electronic and elastic properties of LiX2Ge (X: Rh, Cu, Pd, Ni) Heusler phase compounds were investigated with density functional theory based on the FP-LAPW method implemented in a Wien2k package. PBE-GGA was used as an exchange and correlation potentials. The lattice constants, total energy, bulk modulus and cohesive energy of these compounds were determined. The density of states (DOS), electronic band gap and electron density were depicted. All compounds were revealed the metallic feature. The elastic properties of these structures were investigated employing the cubic-elastic code developed by Jamal and elastic code developed by Golesorkhtabar et al. The elastic constants, bulk modulus, Young's modulus, shear modulus, Poisson's ratio, Debye temperature, and elastic anisotropy factor of all compounds were calculated. It is concluded that all the structures were mechanically stable because they confirmed to Born's criteria. These results were also found to be in good agreement with previous studies and experimental data.Öğe The effect of hydrostatic pressure on optoelectronic and thermoelectric properties of materials: Band-gap engineering by DFT(Nova Science Publishers, Inc., 2024) Aliabad, H.A. Rahnamaye; Balci, Gulten KavakIn density functional theory DFT, the determination of accurate band gap of materials by band-gap engineering plays a key role in the prediction of optoelectronic and thermoelectric properties of materials. In a solid, the energy difference between the top of the valence band and the bottom of the conduction band is a band gap where no electron state can exist. Controlling the band gap allows us for the production of highperformance optoelectronic as well as thermoelectric devices. Metals have a zero band gap since there is an overlap between the valence and conduction bands. In a semiconductor, there is a band gap of around 1 eV while the band gap of insulators is much larger than in semiconductors.. © 2024 Nova Science Publishers, Inc. All rights reserved.Öğe Half-Metallic Ferromagnetism in Co2NiSi Full-Heusler Compound(Amer Inst Physics, 2018) Ayhan, Seyfettin; Balci, Gulten KavakIn this work, half-metallic (HM) properties of new Full-Heusler ferromagnetic compound Co2NiSi were studied by means of first principle band structure calculation within the framework of density functional theory (DFT). The structural calculations were performed with PBE-GGA (Perdew, Burke and Ernzerhof) potential. The magnetic and electronic properties were performed with Modified Becke-Johnson potential (mBJ). From the spin-polarized calculations using full-potential linearized augmented plane-wave (FP-LAPW) method, we have investigated structural, electronic and magnetic properties of Co2NiSi compound with both AlCu2Mn and CuHg2Ti structure type. Both compounds are metallic with spin up and have bandgap with spin down configuration. Total magnetic moment of Co2NiSi is calculated 3.07 B and 3.28 B for AlCu2Mn and CuHg2Ti structure type, respectively. The compounds has band gap below to Fermi level with 0.2 eV. So we found the Co2NiSi shows type III half metallic behavior.Öğe Physical Properties of Magnesium Nitridophosphate (Mg2PN3) Compound(Amer Inst Physics, 2018) Ayhan, Seyfettin; Balci, Gulten KavakIn this work, we investigated structural, electronic and optical properties of orthorhombic Mg2PN3 compound. The calculations were performed with full-potential linearized augmented plane-wave (FP-LAPW) method based on Density Functional Theory by using Wien2k packet. PBE-GGA (Perdew, Burke and Ernzerhof) were selected as exchangecorrelation functional. We calculated cell dimensions, bulk modulus and cohesive energy of this compound. The calculated structural parameters have good agreement with experimental works. We calculated DOS curve, electronic band structure, dielectric function, absorption coefficient and optical conductivity parameters. The DOS and electronic band calculations show that Mg2PN3 has indirect band gap with 5.2 eV value.Öğe Synthesis, characterization, crystal structure, and antimicrobial studies of novel thiourea derivative ligands and their platinum complexes(Taylor & Francis Ltd, 2018) Solmaz, Ummuhan; Gumus, Ilkay; Binzet, Gun; Celik, Omer; Balci, Gulten Kavak; Dogen, Aylin; Arslan, HakanN, N-Di-R-N'-(4-chlorobenzoyl) thiourea (Di-R: diethyl, di-n-propyl, din-butyl and diphenyl) ligands (HL1-4) and their Pt(II) complexes (cis[ Pt(L1-4-S, O)(2)]) have been synthesized and structurally characterized by elemental analyses, FT-IR and NMR spectroscopy. HL2 ligand and cis-[ Pt(L-4-S, O)(2)] metal complex have been also characterized by a single-crystal X-ray diffraction study. HL2, C14H19ClN2OS, crystallizes in the monoclinic space group P2(1)/n (no. 14), with Z = 4, and unit cell parameters, a = 11.1405(16) angstrom, b = 9.7015(12) angstrom, c = 14.790(2) angstrom, beta = 106.547(7)degrees. The cis-[ Pt(L-4-S, O)(2)], C40H28Cl2N4O2PtS2 : triclinic, space group P-1 (no. 2), a = 8.9919(3) angstrom, b = 14.7159(6) angstrom, c = 15.7954(6) angstrom, a = 113.9317(18)degrees, beta = 97.4490(18)degrees, and. = 105.0492(16)degrees. Single crystal analysis of complex, cis-[ Pt(L1-4-S, O)(2)], revealed that a square planar coordination geometry is formed around the platinum atom by two sulfur and two oxygen atoms of the related ligands, which are in a cis configuration. In addition, the thiourea derivative ligands and their complexes were evaluated for both their in-vitro antibacterial and antifungal activity. The results have been reported, explained, and compared with fluconazole and ampicillin, used as reference drugs.Öğe Thermoelectric, optoelectronic and magnetic properties of BaLn2ZnO5 (Ln = Eu, Pr, Sm) insulators by GGA/mBJ plus U exchange-correlation approaches(Elsevier, 2022) Aliabad, H. A. Rahnamaye; Vahidi, H.; Samsami, M.; Ahmad, Iftikhar; Balci, Gulten KavakOptoelectronic, magnetic and thermoelectric properties of BaLn(2)ZnO(5) (Ln = Eu, Pr, Sm) insulators are investigated by the full-potential linearized augmented-plane wave (FP-LAPW) method. The electronic results show that the BaLn(2)ZnO(5 )compounds are wide-band-gap insulators and the optical threshold energies are suitable for the ultraviolet detectors and the LEDs. There is an inverse relation between the static dielectric function and the band gap value. The negative values of dielectric function with the high reflectivity are observed in the energy range of 10-12 eV. We find that the magnetic moment at the Ln sites decreases with a decrease in the number of electrons in the f state and the integer value of the total magnetic moment per unit cell confirms the non-metallic nature of BaLn(2)ZnO(5 )compounds. The thermoelectric results by GGA + U show that p-type BaLn(2)ZnO(5)and BaLn(2)ZnO(5 )compounds by 1 x 1022 cm(-3) doping can be used in thermoelectric devices.
