Şule Uğur

Şule Uğur
Gazi University · Department of Physics

Professor

About

126
Publications
23,294
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1,335
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Introduction

Publications

Publications (126)
Article
The substitution of Ge with Si in the ZnGeAs₂ chalcopyrite semiconductor and its impact on structural, electronic, optical, and thermoelectric properties have been systematically studied using density functional theory. This study demonstrates the tunability of material properties through alloying, revealing novel insights into the ZnGe₁₋ₓSiₓAs₂ (x...
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This study presents a comprehensive investigation of the electronic, mechanical, and thermodynamic properties of Zintl phase hydrides XGaSiH (X = Sr, Ca, Ba) using Density Functional Theory (DFT) and the FP-LAPW method within the WIEN2k package. Our analysis covers the structural stability, electronic properties, and hydrogen interaction mechanisms...
Article
Elastic, mechanical, anisotropic, electronic, and optical characteristics for the less commonly reported wurtzite (w) crystal structures of CdS, CdSe, and CdTe were investigated using density functional theory plus Hubbard formalism (DFT + U). Presently applied DFT + U methodology captures well the experimental bandgap orders of the w-CdS, w-CdSe,...
Article
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Density functional theory (DFT) calculations were executed for the titled features of hitherto unreported Rb2XS3 (X = Si, Ge, Sn) chalcogen compounds. All compounds were found to be in semiconducting character where they demonstrate high-k dielectric properties, high optical conductivity, high refractivity and reasonable absorbance. In addition, ob...
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Molecular dynamics calculations were performed for the hitherto unclarified temperature-dependent elastic, mechanical, and anisotropic properties of the hexagonal closed pack (hcp) ruthenium (Ru) between 0 and 1200 K. All elastic stiffness constants were found to decrease with increasing temperature. Under the examined temperature range, hcp Ru obe...
Article
Density functional theory (DFT)-based predictions were successfully executed for CaCu2S2. A direct band gap obtained with 1.06 eV is found to be almost in the range of best photovoltaics. The phonon dispersion curve with positive frequencies suggests the easy experimental synthesis of CaCu2S2. Obtained high-absorption, high-refractive index, and hi...
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Since crystal structure dictates the resultant physical properties of materials, titled physical features of the P21 monoclinic SiGe semiconductors, which are still unclear, have been revealed by density functional theory (DFT). The electronic band gap value with 0.49eV was found to be in the order of previously published cubic and hexagonal closed...
Article
To study the structural properties of X2Se2C (X = Ta, Nb) MXenes, we have used an FP-LAPW method based on functional density theory GGA-PBE-sol, which is based on the method of plane waves increased by linear waves at full potential. From the most stable state, we determined other properties such as electronic, optical, and mechanical ones. Band st...
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Recent nanoscience and technology are rapidly progressing with both experimental and theoretical surveys to discover and propose new materials in the fields of semiconductors, optoelectronics, etc. So, in this research, titled physical performances of bulk and monolayered gold cyanides (AuCN) were addressed via density functional theory. Wide indir...
Article
Recent spintronics, thermoelectrics, and quantum computing technologies often desire different types of Heusler alloys because of their extensive uses and versatile properties. Although diverse experiments and theoretical efforts have been dedicated to several Heusler alloys for understanding their key properties, no detailed work has yet been perf...
Article
Materials displaying anomalous quantum confinement effects (aqce) comprise the significant materials for recent optoelectronics, two-dimensional (2D) heterojunctions and band-gap engineering. Although available literature involves numerous works for regular 2D materials, there is still a lack of the key physical properties of aqce materials. So, in...
Article
Density functional theory (DFT) calculations were conducted for the electronic and optical properties of the bulk, unstrained and strained monolayers of SrS2. Electronic band structures of the bulk SrS2 indicated an indirect bandgap with 1.32 eV, whereas the SrS2 monolayer displayed a higher indirect bandgap with 1.95 eV. Biaxial tensile strains of...
Article
Our calculations allowing to establish a link between atomic topology and properties, based on the interpretation of the electronic structure. ScXCo2Sb2 (X = V, Nb and Ta) double half-Heusler alloys (DHH) are nonmagnetic materials. Based on an ab initio study these materials is found to be semiconductors with an indirect band gap in the range 0.56–...
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A density functional theory-based calculation of the magnetic structure, mechanical stability, electronic, and optical properties of quaternary Heusler alloys (QHAs) such as ZrCoFeX (X = Si, Ge) has been conducted. The most stable structure has been found among the various crystal arrangements of the alloys. Half-metallic ferromagnetism was obtaine...
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Zr-Ti-X ternary alloys are striking materials of the latest technology because of their excellent and desired mechanical aspects. Therefore, electronic, elastic, mechanical and anisotropic properties of ZrTiX4 (X=Cr, Mo, W) alloys were probed in this work for the first time via density functional theory (DFT) calculations. The computed electronic b...
Article
Analyses based on first-principles simulations have revealed new details about the mechanical and thermodynamic characteristics of NaBH4 and NaAlH4 complex hydrides in α, β and γ phases. Using the quasi-harmonic Debye model, thermal parameters like the Debye temperature, the heat capacity, and the thermal expansion coefficient of NaXH4 (X = B, Al)...
Article
The main objective of this work is to highlight several physical behaviors of two new compounds (MgS2 and MgSe2) in the cubic structure of the Pa-3 space group, particularly their mechanical and dynamical stabilities, their electronic behaviors and to provide a detailed analysis of bonding between the different atoms and the identification of weak...
Article
The thallium substitution effect on structural, electronic, and optical properties of chalcopyrite-type material AgGaS2 is investigated via first-principles approaches. The computed band gap energy of pure AgGaS2 is about 2.59 eV using Tran-Blaha (TB)-modified Becke Johnson (mBJ) exchange potential, which is in good accord with experimental measure...
Article
Titanium-based alloys are still fascinating materials of today's technology with prevalent use in aviation, biomaterial and automobile industries because of their superior mechanical properties. Further, Ti-5Al-XSn alloys can be defined as the second popular grades after the pioneer Ti-6Al-4V (Ti64) grades. Although it is possible to find many expe...
Article
First-principles calculations were carried out for the electronic, elastic, mechanical and anisotropic behavior of W3XC2 (X: Si, Ge and Al) alloys. Electronic bands analyses reveal an obvious metallic character for all of the investigated alloys. In addition, the calculated magnitudes of Young's modulus of the alloys follow the range of W3SiC2> W3A...
Article
DyOs4P12 is a ferromagnetic metal that has a very low Curie temperature of about 2 K. This work will offer a wide-ranging theoretical study complementary to experimental work on this compound. The found results have confirmed the mechanical stability of DyOs4P12 under slight mechanical strains and the elastic anisotropy analysis has shown that it i...
Article
We report the structural, elastic, mechanical and electronic properties of nitrogen (N)-doped cubic diamond up to 25%N doping concentrations in the steps of 5%N dopant. Our calculations were performed with the generalized gradient approximation functional of density functional theory with the Perdew–Burke–Ernzerhof exchange–correlation energy throu...
Article
We theoretically investigated the structural, elastic and mechanical properties of Ti–15Nb–xGe alloys with x = 0.8, 1, 1.2, 1.4, 1.6 and 1.8 (wt%) compositions for the first time. Theoretical calculations were performed with the generalized gradient approximation (GGA) functional within density functional theory (DFT). We employed the Perdew–Burke–...
Article
First-principles density functional theory (DFT) study calculations were performed for various elastic and mechanical properties of Ti64, Ti6242 and Ti6246 alloys. Generalized gradient approximation and the Perdew–Burke–Ernzerhof scheme of DFT were employed to present calculations together with virtual crystal approximation. All of the investigated...
Article
We report some unclarified physical properties of Ce3XY (X = Al, In and Y = C, N) inverse cubic perovskites by conducting a density functional theory (DFT) study. The elastic, mechanical, magnetic, thermodynamic and optical properties of these compounds were addressed. Obtained elastic data prove the mechanical stability, elastic anisotropy and bri...
Article
We performed density functional theory (DFT) calculations to explore the electronic, optical, elastic and thermoelectric properties of Nb2WNi alloy for the first time by addressing the two different crystal structures (Cu2MnAl and Hg2CuTi) of the alloy. The calculated elastic constants results prove the mechanical stability for both crystal structu...
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We have addressed the several unpublished elastic, mechanical, optical, anisotropic and magnetic properties of V2NiSb inverse Heusler alloy through the density functional theory (DFT) framework. Calculated elastic constants indicate mechanical stability and ductile mechanical character of the alloy. The alloy has high elastic anisotropy. Some optic...
Article
First principles calculations were carried out on the SrMoO4 compound which has been of interest owing to its technologically important physical properties. The structural, electronic, optical and thermal properties of this compound have been investigated under low pressure (LP) through the full potential linearized augmented plane wave method (FP-...
Article
We report the electronic, elastic, mechanical, optical, and magnetic properties of Rh2MnX (X = Ti, Hf, Sc, Zr, Zn) Heusler alloys performed within density functional theory. The generalized gradient approximation was used for calculations in the context of the Perdew–Burke–Ernzerhof exchange‐correlation energy treatment. The computed elastic consta...
Article
We have theoretically investigated the elastic, mechanical, optical and magnetic properties of Ru2MnX (X = Nb, Ta, V) Heusler alloys within density functional theory (DFT). The generalized gradient approximation (GGA) was employed to research with Perdew-Burke-Ernzerhof (PBE) exchange-correlation energy. Obtained elastic constants and elastic modul...
Preprint
We report the electronic, elastic, mechanical, optical and magnetic properties of Rh2MnX (X=Ti, Hf, Sc, Zr, Zn) Heusler alloys performed within density functional theory (DFT). The generalized gradient approximation (GGA) was used for calculations in the context of the Perdew-Burke-Ernzerhof (PBE) exchange-correlation energy treatment. The computed...
Article
We report the structural, elastic, electronic, optical and vibrational properties of double half Heusler (DHH) compounds Ti2FeNiSb2 and Ti2Ni2InSb within density functional theory (DFT) for the first time. The calculated elastic constants express that both compounds are mechanically stable and show ductile mechanical character. Computed band struct...
Article
Several magnetic, electronic and elastic behaviors of HoFe4P12 filled-skutterudite remain unknown, therefore, this study is complementary to the experimental works carried out on this compound. Experimental results have shown that HoFe4P12 shows a ferromagnetic transition at around 5 K, therefore, the ground state properties studied in this work ha...
Article
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Ab initio predictions for strontium chalcogenides such as SrS, SrSe, and SrTe doped with magnetic titanium (Ti) element as the Sr1 − xTixX (X = S, Se, and Te) diluted magnetic semiconductor (DMS) compounds in rock-salt ferromagnetic structure have been studied at concentration x = 0.25, by using the full-potential linearized augmented plane wave pl...
Article
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Cation disorder in cobalt ferrite spinels have significant effects on its electronic, magnetic and optic behavior. The cations inversion effect between tetrahedral (Td) and the octahedral (Oh) positions on electronic and magnetism in Co1−yFey(CoyFe2−y)O4 with 0 ≤ y ≤ 1 cobalt ferrites is reported. It is found that cobalt ferrites exhibit strong fer...
Article
Weak interactions are not negligible in layered structures and contribute strongly in their physical behaviors. Thanks to NL-vdW functionals and analysis methods of the electron density, their analysis is possible, which allows to better understand their effects on the different physical properties of solids. We have studied the role of weak intera...
Article
We report the structural, elastic, mechanical, electronic and optical properties of Ba2K2Te2O9 (dibarium dipotassium nonaoxidoditellurate) triple perovskite compound by employing generalized gradient approximation (GGA) of first principles density functional theory (DFT) within Perdew-Burke-Ernzerhof (PBE) exchange correlation energy for the first...
Article
Solar-assisted water splitting using photoelectrochemical cells (PECs) is one of the promising ways for the production of hydrogen to store renewable energy. Semiconducting materials are used as a key factor which controls the overall energy conversion efficiency in PECs. However, finding new semiconductors with appropriate properties (stability, e...
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In this contribution, we report the results of theoretical calculation on the pressure induced phase transitions, structural, electronic and optical properties of the lithium based ternary LiBeX (X= As, Sb, Bi) compounds. These calculations are carried out using the full potential linearized augmented plane wave method. Our results show that these...
Article
Although numerous theoretical studies are available for the band gap energies of distinct silica (SiO2) polymorphs, some of the calculated results of these former studies still remain inconsistent and mostly disagree with the experimental data of the investigated polymorphs. To obtain more reasonable results, we have focused on the band gap energie...
Article
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Using PP-APW method the electronic, optical and mechanical anisotropy of ZnRE2S4 (RE = Er, Tm) olivine compounds was investigated. The calculated unit cell parameters are in good agreement compared to the experimental ones. In addition, the study of electronic properties reveals that ZnEr2S4 and ZnTm2S4 are semiconductors with a direct bandgap of a...
Article
A DFT study of homonuclear X 2 ([Formula: see text], As, Se, Sc, Ti, V, Cr, Mn, Fe, Co, Cu, Zn) is presented using PBEO exchange (xc) functional which is a mixing of Perdew–Burke–Ernzerhof (PBE) and Hartree Fock (HF) exchange energy. However, we used cc-pVXZ and aug-cc-pVXZ basis sets where X is maximum angular momentum number in basis set. Converg...
Article
Full-text available
First principles calculations have been used to investigate the structural phase transitions and lattice dynamics in the alloy Lix Na1-xMgH3. The density functional perturbation theory (DFPT) and the virtual crystal approximation (VCA) are employed, within the generalized gradient approximation. Our total energy and formation energy results show th...
Article
First Brillouin zone-centre phonon frequencies, elastic stiffness and mechanical properties of the Ln2Hf2O7 [Ln: La, Nd, Sm and Eu] pyrochlore structure were predicted by using an eight parameter bond-bending force constant model. One of the preliminary results of our study is that all the examined compounds are mechanically stable, and the elastic...
Article
We performed first principles calculations to determine the typical cubic elastic constants (C11, C12 and C44), bulk modulus (B), shear modulus (G) and Young’s modulus (E) of TlBr and TlCl compounds. We employed two different GGA functionals, the Perdew-Wang 1991 (PW91) and the Perdew-Burke-Ernzerhof (PBE) for the exchange and correlation energy to...
Article
Several previous works have shown that (Lenaite) AgFeS2 has a chalcopyrite structure with I-42d space group, but several information about its magnetic and optoelectronic behavior remain still unknown. The study of these properties is the main objective of our work, which is based on several theoretical approaches. The determination of the most sta...
Article
Full-text available
Based on the density functional theory (DFT) implemented by the wien2k code which uses the full potential linearized augmented plane wave plus local orbitals (APW + lo) method, we have been able to study different physical properties of XPN2 (X = Li, Na) chalcopyrite such as structural, electronic, elastic and thermoelectric properties. According t...
Article
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In this study, an eleven-parameter rigid-ion model (RIM) is proposed for BaFX (X = Cl, Br and I) matlockite structure compounds. The interatomic interactions up to fourth nearest neighbors for the studied compounds are calculated. The zone-center raman and infrared phonon mode frequencies, elastic constants, bulk modulus B, shear modulus G, Young’s...
Article
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In the present study ab initio methology under density functional theory with generalized gradient approximation is used to study the structural, elastic, and vibrational properties of TiMg2O4 with cubic and tetragonal phases with space groups (Fd\( \overline{3} \)m) and P4_122, respectively. The present study shows that the studied compound TiMg2O...
Article
Structural, elastic, electronic and vibrational properties of XAl2O4 (X = Ca, Sr and Cd) compounds with orthorhombic structure are studied by first principles method within generalized gradient approximation. The calculated negative formation enthalpy for each compounds indicates the thermodynamical stability of the studied phase. Band structure ca...
Article
According to several previous works, Li2S2 occurs during discharge of lithium–sulfur (Li–S) batteries. Several information on the physical properties of this compound remain unknown including those of its ground state. In this work, a study of the pressure effect on the elastic and optoelectronic properties of Li2S2 in its tetragonal structure of P...
Article
XLa2S4 (X = Ba; Ca) sulfides are widely used as materials for application in infrared region, but the theoretical studies on these materials are limited and incomplete. Using the augmented plane wave + local orbitals (APW + lo) method with different approximation functionals, we performed a systematic theoretical study on the structural, electronic...
Article
A detailed theoretical investigation on the structural, elastic, electronic, thermoelectric, thermodynamic and optical properties of half-Heusler MRhSb (M = Ti, Zr, Hf) compounds is presented. The computations are carried out using the full potential linear augmented plane wave method (FP-LAPW) within density functional theory (DFT). The optimized...
Article
In this manuscript, the electronic structure, bonding nature and optical properties of the ternary Ba2HgS5 compound was investigated using the density functional theory (DFT). The generalised gradient approximation (GGA), Engel and Vosko generalised gradient approximation (EV-GGA) and the modified Becke Johnson (mBJ) schemes were used to model the...
Article
The concentration dependence of the phase stability, half-metallicity, thermal and magnetic properties of Fe2MnxNi1−xSi (0 ≤ x ≤ 1) Heusler alloys in two structures, Cu2MnAl (Fm3m) and Hg2TiCu (F43m), were investigated at the ab initio level using density functional theory. The exchange–correlation term was assessed using local spin density (LSDA)...
Article
Full potential band structure calculations have been performed on the NiAs (hexagonal), MnP (orthorhombic) and Zinc-blende structures of MnAs1−xPx (0 ≤ x ≤ 1) alloys. The stability of the ferromagnetic state is investigated by comparing the total energies for paramagnetic (P), ferromagnetic (F) and antiferromagnetic (AF) state, where different type...
Article
First-principles density functional theory (DFT) calculations within generalized gradient approximation (GGA) are carried out to investigate the structural, electronic, mechanical, lattice dynamical and thermodynamic properties of Ti2AN (A = Si, Ge and Sn) MAX phases. The optimized geometrical parameters such as lattice constants (a, c) and the int...
Article
We report the results of the FP-APW + lo calculations of the structural, electronic, optical and thermo-electric properties of the CdY2Ch4 (Ch = S, Se) compounds under hydrostatic pressure effect. The calculated ground state properties agree well with the available experimental data. The investigated materials are semiconductors, with direct band g...
Article
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First-principles calculations were used to calculate the structural, electronic and half-metallic ferromagnetism of Mn2RuGe1-xSnx (x=0, 0.25, 0.50, 0.75, 1) Heusler alloys. The Hg2CuTi-type structure is found to be energetic more than Cu2MnAl-type structure for both Mn2RuGe and Mn2RuSn compounds. The calculated lattice constants for Mn2RuGe and Mn2...
Article
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The structural, electronic, elastic and thermodynamic properties of Curium Monopnictides CmX (X = N, P, As, Sb and Bi) are investigated using first-principles calculations based on the density functional theory (DFT) and full potential linearized augmented plane wave (FP-LAPW) method under ambient condition and high pressure. The exchange-correlati...
Article
First principles density functional theory calculations were performed to study structural, electronic, elastic, optical and vibrational properties of CoAl2O4 and MnAl2O4 aluminate spinels. Computed ground state properties such as unit-cell parameter and oxygen positional parameter differ by less than 1% from previously available theoretical and ex...
Article
The phase diagrams of Yb-Cd and Yb-Sn systems were calculated by coupling the CALPHAD method and ab initio calculations. The enthalpies of formation of nine binary compounds (YbCd, αYbCd2, Yb2Sn, αYb5Sn3, βYb5Sn3, Yb5Sn4, YbSn, Yb3Sn5 and YbSn3) were determined via ab initio density functional theory using the VASP code. Based on the available expe...
Article
A comprehensive study of structure, phase stability, electronic, vibrational and thermodynamic properties of LiMgSb and LiZnSb compounds is performed by carrying out First-principles calculations within density–functional theory using the full potential linearized augmented plane wave (FP-LAPW) combined with the pseudo-potential method. The general...
Article
Structural and elastic properties of silver chromate in normal (CrAg2O4) and inverse (Ag2CrO4) spinel structure have been studied using density functional theory (DFT) together with PerdeweBurke eErnzerhof (PBE) exchangeecorrelation functional implemented in VASP package. It is observed that studied compound satisfy the well-known requirements of m...
Article
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Using first-principles calculations based on density functional theory, the structural, electronic and thermodynamic properties of Li2CdGeS4 and Li2CdSnS4 compounds are investigated. We confirmed that both Li2CdGeS4 and Li2CdSnS4 are diamond-like semiconductors of the wurtz-stannite structure type based on that of diamond in terms of tetrahedra vol...
Article
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In the present work, we investigate the structural, optoelectronic and thermoelectric properties of the YLi3X2(X = Sb, Bi) compounds using the full potential augmented plane wave plus local orbital (FP-APW+lo) method. The exchange-correlation potential is treated with the generalized gradient approximation/local density approximation (GGA/LDA) and...
Article
Ab initio plane-wave pseudopotential calculations of electronic and vibrational properties have been carried out for the ternary phosphides BaM2P2 (M=Ni,Rh and Ir) with a ThCr2Si2-type structure. The calculated electronic results show the metallic character of BaM2P2, and the plots of total and partial density of states of BaM2P2 exhibit strong hyb...
Article
We report a systematic study of the structural, electronic, optical and elastic properties of the ternary ruthenium-based hydrides A2RuH6 (A = Mg, Ca, Sr and Ba) within two complementary first-principles approaches. We describe the properties of the A2RuH6 systems looking for trends on different properties as a function of the A sublattice. Our res...
Article
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Electronic band structure, optical and thermodynamic properties of ternary hydrides MBeH3 (M = Li, Na, and K) were studied using ab initio density functional theory (DFT). The effect of the adopted approximation to the exchange-correlation functional of the DFT is explicitly investigated by considering four different expressions of two different cl...
Article
We have investigated the ground state and electronic properties of in the structure using a generalised gradient approximation of the density functional theory and the ab initio pseudopotential method. We find that the calculated electronic properties of exhibit three-dimensional rather than two-dimensional characteristics in spite of the apparent...