Cauchy Pressure Research Articles

Temperature-dependent elastic properties of high entropy ceramic (ZrTaNbTi)C from self-consistent quasi-harmonic approximation

High-entropy ceramics have recently attracted considerable attentions because of excellent combination of exceptional properties. In this work, the temperature dependent elastic properties of (ZrTaNbTi)C have been systematically studied from the density functional perturbation theory combined with self-consistent quasi-harmonic approximation. High entropy ceramic (ZrTaNbTi)C is thermodynamically stable due to the negative formation enthalpy, and is also mechanically stable from the obtained elastic properties. The phonon dispersion relation computed at equilibrium volume contains no imaginary-frequency, implying the dynamical stability. At 0 K, (ZrTaNbTi)C possesses evidently high elastic moduli and hardness. The calculated electronic density of state and Bader charge at 0 K and 2000 K show that (ZrTaNbTi)C have covalent characteristics accompanied by ionic feature while the covalency decreases and the ionicity increases as temperature increases. The temperature-dependent elastic properties show that (ZrTaNbTi)C is mechanically stable in temperature range studied, and remains high strength and hardness at high temperature due to the slight softening of strong covalent bonding. Poisson's ratio, Pugh's ratio and Cauchy pressure suggest the higher brittle-ductile transformation trend as the temperature increases. Moreover, (ZrTaNbTi)C shows less anisotropy at higher temperature from the Zener index AZ and three-dimensional projections, being beneficial to reduce cracking and improve durability. The present study provides more insight into the high temperature behavior of mechanical properties, would be valuable for understanding and design of high-temperature properties of high entropy carbide ceramics.

First-principles study of structural, electronic, elastic, vibrational and thermodynamics properties of LaX3 (X=Sn, Tl, Pb and Bi) compounds under pressure

The structural, electronic, elastic, vibrational and thermodynamics properties of the LaX3 (X = Sn, Tl, Pb and Bi) compounds in AuCu3 type structure have been calculated using first-principles method based on the density functional theory (DFT). From the calculated electronic band structure of LaX3, we can see that the energy band structure near the Fermi level is mainly composed of X p orbitals and La d orbitals. With the enhancing pressure, the electrical conductivity decrease gradually and the electron transition becomes more difficult. Moreover, the elastic constants (C11, C12, C44) and the values of bulk modulus B, shear modulus G, Young's modulus E increase with pressure. In addition, the change of Poisson's ratio, Cauchy pressure, anisotropy index Au and the ratio of bulk modulus to shear modulus B/G of these compounds with pressure show that the four compounds remain ductile. Finally, it is the first time that the thermodynamics properties were investigated in the range of 0–50 GPa and 0–600 K. Using the phonon calculations, we found that the temperature effect on the thermodynamics properties is much greater than the pressure effect. Particularly, the phonon dispersion curves and phonon density of states at 0 GPa are discussed and the infrared active phonon modes at Γ point under pressure are reported.

Structural, electronic, magnetic, elastic and thermodynamic properties of Ni 4 N anti-perovskite

ABSTRACT We have analyzed the structural, electronic, magnetic, elastic and phonon properties of anti-perovskite by using density functional theory (DFT) based on the generalized gradient approximation scheme and Monte Carlo simulations within the Ising model. The structural investigation exposes the ferromagnetic configuration stability of the compound. Also, the density of states (DOS) and band structure calculations show a metallic behavior of . The investigated elastic constants, phonon dispersion and density phonon states showed that the compound is mechanically and dynamically stable. We also found that the is ductile from the Poisson's ratio, Pugh's ratio and Cauchy pressure. The thermodynamic parameters like heat capacity, Debye and melting temperature have also been calculated. The critical exponents of obtained by Monte Carlo simulation are highly in agreement with the 3D-Ising model around the critical temperature . The obtained value of agrees reasonably well with available experimental and theoretical works.

MechElastic: A Python library for analysis of mechanical and elastic properties of bulk and 2D materials

The MechElastic Python package evaluates the mechanical and elastic properties of bulk and 2D materials using the elastic coefficient matrix (Cij) obtained from any ab-initio density-functional theory (DFT) code. The current version of this package reads the output of VASP, ABINIT, and Quantum Espresso codes (but it can be easily generalized to any other DFT code) and performs the appropriate post-processing of elastic constants as per the requirement of the user. This program can also detect the input structure's crystal symmetry and test the mechanical stability of all crystal classes using the Born-Huang criteria. Various useful material-specific properties such as elastic moduli, longitudinal and transverse elastic wave velocities, Debye temperature, elastic anisotropy, 2D layer modulus, hardness, Pugh's ratio, Cauchy's pressure, Kleinman's parameter, and Lame's coefficients, can be estimated using this program. Another existing feature of this program is to employ the ELATE package (2016) [29] and plot the spatial variation of several elastic properties such as Poisson's ratio, linear compressibility, shear modulus, and Young's modulus in three dimensions. Further, the MechElastic package can plot the equation of state (EOS) curves for energy and pressure for a variety of EOS models such as Murnaghan, Birch, Birch-Murnaghan, and Vinet, by reading the inputted energy/pressure versus volume data obtained via numerical calculations or experiments. This package is particularly useful for the high-throughput analysis of elastic and mechanical properties of materials. Program summaryProgram Title:MechElasticCPC Library link to program files:https://doi.org/10.17632/y9zc7zybrm.1Developer's repository link:https://github.com/romerogroup/MechElasticLicensing provisions: GPLv3Programming language: PythonNature of problem: To automatize and simplify the analysis of elastic and mechanical properties for bulk and 2D materials, especially for high-throughput DFT calculations.Solution method: This Python program addresses the above problem by parsing the elastic coefficient matrix obtained from the first-principles DFT calculations, does the appropriate post-processing to evaluate the elastic properties, and performs the mechanical stability tests for all crystal classes using the generalized Born-Huang criteria. It can also be used to carry out the equation of state analysis to study the structural phase transitions.Additional comments:MechElastic can be downloaded using the below link: https://github.com/romerogroup/MechElasticInstallation (via PyPI): pip install mechelastic, or pip3 install mechelastic

Theory prediction of band structures, densities of states, mechanical and thermodynamic properties of solid solutions BaxK1-xBi0.92Mg0.08O3

The band structures, densities of states, mechanical and thermodynamic properties of solid solutions BaxK1-xBi0.92Mg0.08O3 have been systematically investigated using the pseudopotential plane-wave method based on the first-principles simulation. The obtained lattice parameters are in accordance with the experimental test data. The electronic band structure indicates the metallic character of the considered compound. And the Ef is principally originated from the Bi/Mg:s, p and the O:2p states. The predicted elastic constants Cij reveals that BaxK1-xBi0.92Mg0.08O3 is mechanically stable. The polycrystalline modulus such as Young's modulus E, shear modulus G and bulk modulus B are obtained in the framework of the Voigt-Reuss-Hill arithmetic mean approximation. Cauchy pressure Cp and B/G ratio are further investigated in order to probe the ductile/brittle nature of solid solutions. Additionally, the anisotropy is forecasted by the Zener factor Z, AG, Au and 3D surface of E. Finally, the Vickers hardness Hv and the Debye temperature θD have been obtained. We believe that our theoretical results can provide information for further experimental and theoretical researches.

Structural, elastic, electronic, thermal, and phononic properties of yttrium carbide: First-principles calculations

In this paper, structural, electronic, elastic, phononic, and thermal properties of YC in both rock-salt (B1) and CsCl (B2) phases are studied. Calculations have been performed by using QUANTUM-ESPRESSO/PWSCF computational package which is based on density functional theory (DFT) and pseudo-potential method. Local density approximation (LDA) and generalized gradient approximation (GGA) have been used for modeling the exchange and correlation effects. According to the total energy diagram versus unit cell volume, the YC compound in the B1 phase is more stable than that of the B2 phase at ambient pressure. The computed elastic parameters indicated that the B2 phase did not satisfy the mechanical stability conditions at ambient pressure and is considered to be an unstable phase of the YC structure.The analysis of the enthalpy versus pressure diagram predicts that the structural phase transition from the B1 phase to the B2 phase occurs at pressures 51 GPa and 71.5 GPa, for various LDA and GGA approximations, respectively. Based on the phonon dispersion curves at ambient pressure, the B1 phase of the YC compound is dynamically stable, while at high pressure, the YC compound in the B2 phase has shown stability. Using calculated elastic constants, the small amount of Zener anisotropy factor A shows a strongly anisotropic nature of the YC structure. The higher amount of the calculated Poisson's ratio (~0.40) than that of the corresponding critical value (~0.33) together with the positive values of Cauchy pressure within the LDA and GGA approximations present the ductility and metallic behavior of the YC compound in the B1 phase. The band structure and total density of states calculations also verify the metallic behavior of the YC compound in the stable B1 phase. From PDOS calculations, overlapping the 4d orbital of the Y atom and 2p orbital of the C atom near the Fermi level indicates that these orbitals have significant contributions to the bonding between the Y and C atoms. This bonding is substantiated by the corresponding electron density distribution. The thermodynamic calculations indicated that the heat capacity increases regularly and continuously with the increase in temperature T, toward the classical Dulong-Petit value of 6R for the bulk structure of the YC compound with two atoms in the primitive cell. It can also be predicted for the YC compound that the smaller lattice parameter within the LDA approximation compared to the GGA approximation causes stiffness increases, followed by an increase in the Debye temperature. The increasing trend of entropy versus temperature indicates the endothermic behavior of the YC compound.

Explorations of elastic anisotropies and thermal properties of the hexagonal TMSi2 (TM = Cr, Mo, W) silicides from first-principles calculations

In this study, the first-principles (DFT) is used to explore the structural properties, elastic anisotropies, and thermal properties of hexagonal TMSi2 (TM = Cr, Mo, W) silicides. The elastic properties of single-crystal and poly-crystal are acquired by using Voigt-Reuss-Hill approximations method. The hardness of TMSi2 silicides were calculated from the bulk B and shear moduli G; In addition, the results show that hexagonal TMSi2 silicide is not potentially super-hard materials. Meanwhile, in terms of their Poisson’s ratio, GH/BH and Cauchy pressures, TMSi2 silicides are brittle material. Elastic anisotropies of TMSi2 silicides are measured by using anisotropy index of elastic properties, 3D surface constructions of elastic moduli and their two-dimensional planar projections were used to indicate the elastic anisotropies of these TMSi2 silicides. The sequence of elastic anisotropy follows as WSi2 > MoSi2 > CrSi2. Finally, the sound velocities, Debye temperatures, thermal conductivity and their anisotropies of these silicides were discussed, the sound velocities and Debye temperature of these TMSi2 silicides are anisotropic in the [100] and [001] directions.

Electronic band structure, mechanical and thermodynamic properties of Erbium chalcogenides ErX (X = S, Se and Te): A computational insight

We have investigated the structural, electronic, magnetic, mechanical, and thermodynamic properties of Erbium chalcogenides, ErX (X = S, Se and Te) using a suitable density functional theory (DFT) approach. ErX compounds were found stable in NaCl-type structure and in the ferromagnetic phase. The electronic band structure diagrams showed metallic nature of the ErX compounds in both the majority and minority spin channels. Higher value of the bulk modulus for ErS showed high stiffness resistance as compare to other two members. The calculated total magnetic moments were found to be 2.18 μB, 2.17 μB, and 2.22 μB for ErS, ErSe and ErTe compounds, respectively. The major contribution in the magnetic moment was found due to f -electrons of Er. The elastic and mechanical properties have also been computed. The calculated values of bulk modulus to shear modulus (B/G) and Cauchy pressure indicated their brittle nature. As per the Zener anisotropy factor, these materials were also found to be elastically anisotropic. The thermodynamic constants including the bulk modulus, specific heat at constant volume, thermal expansion coefficient, entropy and Debye were calculated for ErX compounds for the first time.

Origin of high hardness and optoelectronic and thermo-physical properties of boron-rich compounds B6X (X = S, Se): A comprehensive study via DFT approach

In the present study, the structural and hitherto uninvestigated mechanical (elastic stiffness constants, machinability index, Cauchy pressure, anisotropy indices, brittleness/ductility, Poisson's ratio), electronic, optical, and thermodynamic properties of novel boron-rich compounds B6X (X = S, Se) have been explored using density functional theory. The estimated structural lattice parameters were consistent with the prior report. The mechanical and dynamical stability of these compounds have been established theoretically. The materials are brittle in nature and elastically anisotropic. The value of fracture toughness, KIC for the B6S and B6Se, are ∼ 2.07 MPam0.5, evaluating the resistance to limit the crack propagation inside the materials. Both B6S and B6Se compounds possess high hardness values in the range of 31–35 GPa and have the potential to be prominent members of the class of hard compounds. Strong covalent bonding and sharp peak at low energy below the Fermi level confirmed by partial density of states (PDOS) resulted in the high hardness. The profile of band structure as well as density of states assesses the indirect semiconducting nature of the titled compounds. The comparatively high value of Debye temperature (ΘD), minimum thermal conductivity (Kmin), lattice thermal conductivity (kph), low thermal expansion coefficient, and low density suggest that both boron-rich chalcogenides might be used as thermal management materials. Large absorption capacities in the mid-ultraviolet region (3.2–15 eV) of the studied materials and low reflectivity (∼16%) are significantly noted. Such favorable features give promise to the compounds under investigation to be used in UV surface-disinfection devices as well as medical sterilizer equipment applications. Excellent correlations are found among all the studied physical properties of these compounds.

Investigation of structural, electronic, magnetic, elastic and thermodynamic properties of Mn3GaN antiperovskite by first principle and Monte Carlo simulations

ABSTRACT Structural, electronic, magnetic, elastic and thermodynamic properties of anti-perovskite have been studied using the first-principles calculations based on density functional theory (DFT) and Monte Carlo simulations within the Ising model. The structural investigation exposes the antiferromagnetic configuration stability of the compound. Also, the density of states (DOS) and band structure calculations show a metallic behaviour of . The computed elastic constants, phonon dispersion and density phonon states calculations demonstrate that the compound is mechanically and dynamically stable. The calculated results of Poisson's ratio, Pugh's ratio and Cauchy pressure show that the is ductile material with a metallic bond. The thermodynamic parameters like heat capacity, Debye and melting temperature have also been calculated. The exchange coupling of has been calculated to obtain the critical temperature () from Monte Carlo calculations. The obtained value of (288 K) is in good agreement with other experimental and theoretical works.

Insight into glass transition temperature and mechanical properties of PVA/TRIS functionalized graphene oxide composites by molecular dynamics simulation

Mechanical properties of polyvinyl alcohol (PVA) are of essential importance to the practical application. Much effort has been done to further improve the properties of PVA by modifiers. However, in-depth insight into the role of the modifiers in the properties of PVA at a molecular level still remains rare. Therefore, the Glass transition temperature (Tg) and mechanical properties of PVA, PVA/graphene oxide (GO) and PVA/TRIS functionalized graphene oxide (Tris-GO) are investigated by molecular dynamics (MD) simulation. The results indicate the volume of PVA, PVA/GO and PVA/Tris-GO regularly varies with temperature. The PVA/Tris-GO show a higher Tg compared to the PVA/GO owing to stronger hydrogen-bonding interactions. The Young’s modulus, Shear modulus and Cauchy pressure of PLA/Tris-GO nanocomposites are enhanced by 50%, 46%, and 40% at 2.5 wt% addition amount of Tris-GO. In addition, the introduction of Tris-GO can significantly reduce the mobility and flexibility of the PVA chains in the PVA/Tris-GO. The binding energy between PVA and Tris-GO is larger than that between PVA and GO, which leads to the improved mechanical properties of the PVA/Tris-GO. These simulation results provide a better understanding of the thermomechanical mechanism of PVA/Tris-GO nanocomposites, and an effective guidance for improving their mechanical properties.

A first principle investigation of the non-synthesized cubic perovskite LiGeX3 (X=I, Br, and Cl)

A self-consistent calculation within Density Functional Theory (DFT) using norm-conserving pseudopotential plane-wave and the precise hybrid functional HSE06 were performed. The stability, elastic, originatemechanical, electronic, and optical properties of the cubic perovskites LiGeX3 (X = Br Cl, and I) are investigated. The behaviour of the stability and elastic characteristics under hydrostatic pressure is also presented and studied. Band structure analysis using PBE, GW-Approximation, and HSE06, show that LiGeX3 (X = Br Cl, and I) are direct bandgap semiconductors. The structures are most stable at the computed relaxed lattice parameters (a=b=c=5.880,5.470and5.190Ao)for the LiGeI3, LiGeBr3, and LiGeCl3, respectively. The Pressure dependence of cubic perovskite elastic moduli, bulk modulus B, shear modulus/constant (G,Cs), Young's modulus E, the Poisson's ratio σ, Vickers hardness Hv, Lame's constants (λ,μ), Cauchy pressure C12−C44, the Anisotropy factor A, Kleinman parameter ζ, and the P-wave modulus Pw, elastic wave velocities v, Debye temperature θD is presented. The optical properties including the static refractive index and dielectric constant are found to be related to the direct bandgaps, proportionally. The refractive index, extinction coefficient, complex dielectric function, energy loss function, optical conductivity, reflectivity, and absorption coefficient for 0–25eVincident photon energies are also presented.

Theoretical investigations of structural, mechanical, electronic and optical properties of NaScSi alloy

Ab initio density functional theory is employed to investigate the structural, elastic, electronic and optical properties of the half-Heusler NaScSi alloy. The lattice constants are very near to the available theoretical data. In addition, besides the GGA approximation, the modified Becke–Johnson exchange potential is also used to improve the direct X→X band gap value. Furthermore, the elastic constants and related elastic moduli confirm its stability and brittle behaviour in the type I structure. The influence of pressure on Cij constants, bulk modulus B, Cauchy pressure, Poisson ratio ν, shear modulus, B/G ratio and anisotropy factor A are analysed. Additionally, the strong absorption is extended between the visible domain and that of the ultraviolet is predicted.

The pressure effect on the structural, elastic, and mechanical properties of orthorhombic MgSiN2 from first-principles calculations

Pressure effect on lattice parameters, elastic moduli, Poisson's ratio, Cauchy pressure, elastic anisotropy, and Vickers hardness of orthorhombic MgSiN2 by means of first-principles calculations based on density functional theory (DFT) by generalized gradient approximation (GGA) in the functional form by Perdew, Bruke, and Ernzerhof (PBE) of the exchange-correlation were presented. The structural properties, elastic moduli, B0/G, Poisson's ratio (ν) and Cauchy pressure under pressure up to 10 GPa were calculated. The optimized structural and ground state properties under ambient pressure were in agreement with the available experiments and other calculations. The orthorhombic MgSiN2 was mechanically stable under pressure up to 10 GPa by the elastic stability criteria investigation. Under pressure, the relationship of elasticity in length was C33 > C11 > C22, indicating that it is easier to compress along the b-axis than along the a-axis and c-axis, respectively. The calculated bulk modulus, shear modulus, Young's modulus and Poison's ratio index all increased with an increase in the pressure. The B0/G, Poisson's ratio (ν) and Cauchy pressure analyses implied that orthorhombic MgSiN2 was single crystal, and a critical pressure for brittle-to-ductile transition was found to be 2 GPa. The Cauchy pressure of {100} plane, {010} plane and {001} plane, Vickers hardness (Hv) and the shear anisotropy as a function of pressure were investigated from the calculation.

Theoretically exploring covalent bonding effect on deformability of B2/β Ti(AlxNb1-x) phase

We used density-functional theory to assess the electronic structure, elastic properties and planar fault energies of the B2 Ti(AlxNb1-x) (0.2 ≤ x ≤ 0.8) phase in relation to the composition and chemical ordering. We found that the covalent bonding becomes stronger for B2 Ti(AlxNb1-x) with higher Al concentration and long range order (LRO) parameter. Based on a universal ductile-to-brittle criterion by integrating Pettifor’s Cauchy pressure with Pugh’s modulus ratio, the deformability becomes less for Ti(AlxNb1-x) with higher Al concentration and LRO parameter, which is well correlated with the bonding character. Rice’s ratio has an anti-correlation with Pugh’s modulus ratio for Ti(AlxNb1-x). According to Rice’s criterion, Ti(AlxNb1-x) with various Al concentration and LRO parameter are brittle in pure mode I loading, however, Nb-enriched disordered and low-ordered Ti(AlxNb1-x) may satisfy Rice’s criterion for nucleation of dislocation and thus, are ductile in mode II or III loading. The hardness increases but the fracture toughness decreases obviously with increasing the degree of covalent bonding in Ti(AlxNb1-x).

Prediction of a new Sn-based MAX phases for nuclear industry applications: DFT calculations

Lately, the MAX phases have been gained an enormous technological attention due to their duel inherent metallic and ceramic properties. Herein, we have investigated by means of the full potential linearized augmented plane wave (FP-LAPW) method for determining the structural, mechanical, electronic and thermodynamic properties of 312 MAX phases M3SnC2 (M = V, and Nb). The intended M3SnC2 compounds generally exist in two possible polymorphs α and β polymorph structures. Further, the formation energies are determined meticulously and revealed that V3SnC2 was more stable thermodynamically than Nb3SnC2 compound. Conversely, Nb3SnC2 exposed a superior mechanical properties over V3SnC2 compound. In addition, the elastic constants of these compounds completely satisfied the criteria of the mechanical stability and showed a ductile nature. The Poisson’s ratio and Cauchy pressure have expressed a positive values which signified the ionic characters for the studied compounds. After that, a metallic behavior was confirmed by the electronic structures analysis. Furthermore, the thermodynamic properties such as heat capacity at constant volume and Debye temperature were investigated at high temperature and pressure. The V3SnC2 compound exhibits the highest value of Debye temperature, while Nb3SnC2 possesses a higher melting temperature. The present meticulous study made these compounds as a potential candidates for radiation-tolerant applications.

Ab initio study of the structure, elastic, and electronic properties of Ti3(Al1\u2212nSin)C2 layered ternary compounds

The MAX phase materials such as layered ternary carbides that simultaneously exhibit characteristics of metallic and ceramic materials have received substantial interest in recent years. Here, we present a systematic investigation of the electronic, structural stabilities, and elastic properties of Ti3(Al1−nSin)C2 (n = 0,1) MAX phase materials using the ab initio method via a plane-wave pseudopotential approach within generalized-gradient-approximations. The computed electronic band structures and projected density of states show that both Ti3SiC2 and Ti3AlC2 are metallic materials with a high density of states at the Fermi level emanating mainly from Ti-3d. Using the calculated elastic constants, the mechanical stability of the compounds was confirmed following the Born stability criteria for hexagonal structures. The Cauchy pressure and the Pugh’s ratio values establish the brittle nature of the Ti3SiC2 and Ti3AlC2 MAX phase materials. Due to their intriguing physical properties, these materials are expected to be suitable for applications such as thermal shock refractories and electrical contact coatings.

First principles computation of structural, electronic, magnetic and mechanical properties of new lithium based half Heusler alloys

First principles calculations have been accomplished for structural, electronic, magnetic and mechanical properties of half Heusler (HH) LiYZ ([Formula: see text], Rh and [Formula: see text], Se, Te, Sb) alloys using the density functional theory (DFT) within full potential-linearized augmented plane wave (FP-LAPW) method. To calculate the physical properties, Perdew–Burke–Ernzerhof (PBE) potential and generalized gradient approximation (GGA) are employed. The calculations are accomplished for three phases to obtain the most stable phase. The results of these calculations revealed that Type-III is the most stable of LiRhSe and LiRhSb, Type-I of LiRhAs, LiRhTe, LiRuAs, LiRuSb, LiRuSe and LiRuTe alloys. The structural optimization is obtained by plotting the graphs between minimum volume and the lowest energy of all considered alloys. The results of electronic properties including density of states (DOS) and band structures are also presented. The obtained total magnetic moment (MM) is negative for LiRhSb, LiRuSb, LiRhTe, LiRuTe, while it is positive for LiRhSe, LiRuSe, LiRhAs, LiRuAs Heusler alloys (HAs). To determine the mechanical stability, several parameters such as Poisson’s ratio, Pugh’s ratio, Lame’s coefficient, anisotropy factor, Kleinman parameter, Young’s modulus, Bulk modulus and Cauchy pressure are calculated and discussed in detail.

Effects of Al substitution by Si in Ti3AlC2 nanolaminate

Recently, a series of high-purity Ti3(Al1−xSix)C2 solid solutions with new compositions (x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) have been reported with interesting mechanical properties. Here, we have employed density functional theory for Ti3(Al1−xSix)C2 solid solutions to calculate a wider range of physical properties including structural, electronic, mechanical, thermal and optical. With the increase of x, a decrease of cell parameters is observed. All elastic constants and moduli increase with x. The Fermi level gradually increases, moving towards and past the upper bound of the pseudogap, when the value of x goes from zero to unity, indicating that the structural stability reduces gradually when the amount of Si increases within the Ti3(Al1−xSix)C2 system. In view of Cauchy pressure, Pugh’s ratio and Poisson’s ratio all compositions of Ti3(Al1−xSix)C2 are brittle in nature. Comparatively, low Debye temperature, lattice thermal conductivity and minimum thermal conductivity of Ti3AlC2 favor it to be a thermal barrier coating material. High melting temperatures implies that the solid solutions Ti3(Al1−xSix)C2 may have potential applications in harsh environments. In the visible region (1.8–3.1 eV), the minimum reflectivity of all compositions for both polarizations is above 45%, which makes them potential coating materials for solar heating reduction.

First-principles investigation of structural, elastic, electronic and thermodynamic properties of strongly correlated ternary system: The DFT+U approach

The elastic, thermodynamic and electronic properties of rhombohedra SiFe2O4 spinel-type are investigated using generalized gradient approximation (GGA) and local density approximation (LDA) approach. The results obtained confirmed the failure of bare DFT to produce the fundamental bandgap of strongly correlated systems. By incorporating the Hubbard correction term (U) on Fe 3d electron, the calculated bandgap using GGA + U was found to be 3.86 eV and this value is comparable with experimental data. The Pugh's ratio and Cauchy pressure values demonstrate the ductility nature of SiFe2O4 spinel. The temperature variation with thermodynamic properties descript the stability of SiFe2O4 spinel. The heat capacity at constant volume increases sharply with temperature and tends to the Dulong-Petit limit at high temperature. The reported value of the bandgap lies within near-ultraviolet (UV) wavelength, revealing that SiFe2O4 spinel-type material may be useful for the photo-electrochemical cell of water splitting, flat-panel displays and other optoelectronic applications.