First principles prediction of structural stability, elastic, lattice dynamical and thermal properties of osmium carbides

Deligöz, E.; Özişik, H.; Çolakoğlu, Kemal; Çiftçi, Y.Ö.

doi:10.1179/1743284713y.0000000420

Cited by 9 publications

(3 citation statements)

References 66 publications

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“…While knowledge based ab initio models to predict structure and mechanical, electrical and magnetic properties of metallic glasses are state of the art 7 – 10 , there are no reports on Debye-Grüneisen model to predict the CTEs of metallic glasses in literature. The CTEs of cubic 11 – 17 , tetragonal 16 , 17 , hexagonal and trigonal materials 17 have been calculated by the Debye-Grüneisen model. To our knowledge, the Debye-Grüneisen model has not been applied to amorphous materials yet.…”

Section: Introductionmentioning

confidence: 99%

Thermal expansion of Pd-based metallic glasses by ab initio methods and high energy X-ray diffraction

Evertz

Mušić

Schnabel

et al. 2017

Sci Rep

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Metallic glasses are promising structural materials due to their unique properties. For structural applications and processing the coefficient of thermal expansion is an important design parameter. Here we demonstrate that predictions of the coefficient of thermal expansion for metallic glasses by density functional theory based ab initio calculations are efficient both with respect to time and resources. The coefficient of thermal expansion is predicted by an ab initio based method utilising the Debye-Grüneisen model for a Pd-based metallic glass, which exhibits a pronounced medium range order. The predictions are critically appraised by in situ synchrotron X-ray diffraction and excellent agreement is observed. Through this combined theoretical and experimental research strategy, we show the feasibility to predict the coefficient of thermal expansion from the ground state structure of a metallic glass until the onset of structural changes. Thereby, we provide a method to efficiently probe a potentially vast number of metallic glass alloying combinations regarding thermal expansion.

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Section: Introductionmentioning

confidence: 99%

Thermal expansion of Pd-based metallic glasses by ab initio methods and high energy X-ray diffraction

Evertz

Mušić

Schnabel

et al. 2017

Sci Rep

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“…Electronic transport may depend on many factors, such as the electronic structure, lattice vibrations (phonons), defect structure, and related scattering mechanisms [49]. Metallicity for metallic compounds can be quantified using equation (1) [50]:…”

Section: Electronic Propertiesmentioning

confidence: 99%

Pressure effects on the structural, electronic, elastic, optical, and vibrational properties of YMg intermetallic compounds: a first-principles study

Ciftci,

Çatıkkaş

2024

Phys. Scr.

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The properties of YMg in B2 structure have been comprehensively analysed using the first-principles plane-wave pseudopotential method. Specifically, the structural, electronic, elastic, vibrational, and optical properties were investigated using the generalized gradient approximation (GGA) method in the context of density functional theory. The Vienna ab initio simulation package (VASP) was utilized for these calculations. The computed lattice parameter (3.803 Å) and bulk modulus (41.33 GPa) are consistent with the earlier data on ambient pressure. The electronic band structure and energy-dependent density of states reveal the metallic nature of the titled compounds. The Born stability requirements confirmed the mechanical stability. The analysis of Pugh's and Poisson's ratios and Cauchy's pressure reveals that YMg is ductile under the pressures in consideration. According to several anisotropy indices, the compound is noticeably anisotropic both in ambient and under pressure. Our investigation includes an analysis of several fundamental mechanical parameters of the material, including the bulk modulus, the pressure derivative of the Zener anisotropy factor, Poisson's ratio, isotropic shear modulus and Young's modulus with a particular focus on their dependence on pressure. We have determined that the elastic constants obtained remain mechanically stable, satisfying the Born Stability conditions even at high pressures of up to 60 GPa. To explore the dynamic stability of YMg, we analysed the material's phonon dispersion curves. The examined compound displays stability under dynamic conditions from 0 GPa to 30 GPa, as evidenced by its positive vibration frequencies. However, this stability is not sustained under higher pressure, as the compound becomes unstable after 30 GPa to 70 GPa. The electronic band structure and density of states diagrams demonstrate YMg's metallic properties. At atmospheric pressure (0 GPa), the total density of states (TDOS) near the Fermi level is approximately 1.63 states/eV, with pressure application reducing DOS. The dielectric function, refractive index, and energy loss spectra are examined within the 0–20 eV energy range. YMg exhibits its highest absorption between 4 and 11 eV. The peak optical conductivity is observed around 0.78 eV (equivalent to 1589.5409 nm), while the most significant energy loss occurs at 11.90 eV, roughly corresponding to 2.8 Hz in the ultraviolet spectrum. Moreover, we extensively analyzed the material's phonon thermodynamic and optical properties, providing insights into its behavior under various conditions. The outcomes acquired at zero pressure are generally coherent with the current theoretical values.

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“…Elastic constant data can be used for calculating the Debye temperature by estimating it from the average sound velocity (v m ). [49,50] Mostly for hard materials it is higher or vice versa. [51] All of the considered systems are soft materials due to their low Debye temperatures.…”

Section: Polycrystalline Propertiesmentioning

confidence: 99%

Physical properties of ternary thallium chalcogenes Tl₂MQ₃ (M = Zr, Hf; Q = S, Se, Te) via ab-initio calculations

Ateser¹,

Okvuran²,

Çiftçi³

et al. 2019

Chinese Phys. B

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We have reported a first principles study of structural, mechanical, electronic, and thermoelectric properties of the monoclinic ternary thallium chalcogenes Tl2 MQ 3 (M=Zr, Hf; Q=S, Se, Te). The electronic band structure calculations confirm that all compounds exhibit semiconductor character. Especially, Tl2ZrTe3 and Tl2HfTe3 can be good candidates for thermoelectric materials, having narrow band gaps of 0.169 eV and 0.21 eV, respectively. All of the compounds are soft and brittle according to the second-order elastic constant calculations. Low Debye temperatures also support the softness. We have obtained the transport properties of the compounds by using rigid band and constant relaxation time approximations in the context of Boltzmann transport theory. The results show that the compounds could be considered for room temperature thermoelectric applications ( ZT ∼ 0.9 ).

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First principles prediction of structural stability, elastic, lattice dynamical and thermal properties of osmium carbides

Cited by 9 publications

References 66 publications

Thermal expansion of Pd-based metallic glasses by ab initio methods and high energy X-ray diffraction

Thermal expansion of Pd-based metallic glasses by ab initio methods and high energy X-ray diffraction

Pressure effects on the structural, electronic, elastic, optical, and vibrational properties of YMg intermetallic compounds: a first-principles study

Physical properties of ternary thallium chalcogenes Tl₂MQ₃ (M = Zr, Hf; Q = S, Se, Te) via ab-initio calculations

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First principles prediction of structural stability, elastic, lattice dynamical and thermal properties of osmium carbides

Cited by 9 publications

References 66 publications

Thermal expansion of Pd-based metallic glasses by ab initio methods and high energy X-ray diffraction

Thermal expansion of Pd-based metallic glasses by ab initio methods and high energy X-ray diffraction

Pressure effects on the structural, electronic, elastic, optical, and vibrational properties of YMg intermetallic compounds: a first-principles study

Physical properties of ternary thallium chalcogenes Tl2MQ3 (M = Zr, Hf; Q = S, Se, Te) via ab-initio calculations

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Physical properties of ternary thallium chalcogenes Tl₂MQ₃ (M = Zr, Hf; Q = S, Se, Te) via ab-initio calculations