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This study presents a comprehensive analysis of the orthorhombic CsCuO, focusing on its structural, electronic, mechanical, and optical properties, which uses the first‐principles plane wave pseudopotential technique and local density approximation methods based on density functional theory. The derived structural parameters closely match the previously reported experimental data. The calculated results show that CsCuO is mechanically stable and exhibits a certain toughness. Research on electronic properties shows that CsCuO is a direct‐bandgap semiconductor. Charge density and population analysis show that covalent bonds are formed between O and Cu. The optical property results show that CsCuO has good passability to incident light, indicating that CsCuO is an excellent transparent material. In the visible and infrared light regions, CsCuO has a low absorption coefficient, mainly manifested as ultraviolet absorption. Reflection is mainly distributed in the high‐energy region and does not exceed 25% in the visible light region. It can be used in fields that require less light reflection and the manufacture of medical ultraviolet disinfection equipment. [ABSTRACT FROM AUTHOR]

In recent years, H2O2 as an excellent rocket propellant has been widely studied. Herein, the initial decomposition mechanism of H2O2 is studied in detail by molecular dynamics simulation based on density functional theory. It is found that when the energy input to H2O2 is low, the mechanism of intermolecular hydrogen transfer is dominant. With the increase of input energy, the breaking of O–O becomes the first step of the initial reaction, H–O fracture becomes the second step, and finally the transfer of hydrogen to produce H2O and HO2. [ABSTRACT FROM AUTHOR]

This article uses first principles to study a single molecular phase of N2O4. The structural, electronic, and vibrational properties of N2O4 under high pressure are calculated. The a‐axis and c‐axis compressibilities are basically the same. The bandgap of N2O4 decreases as the pressure increases; this is because under the action of pressure, the delocalized electrons in the system increase, so the bandgap decreases. There are two main types of N2O4 vibration: telescopic vibration and bending vibration. Herein, the calculated Raman spectrum and infrared (IR) spectrum are compared with the experimental values, and the agreement is better under normal pressure. With the increase of pressure, both the Raman and IR peaks of N2O4 appear blueshifted. This is because the applied pressure reduces the volume of the unit cell and reduces the distance between atoms, causing the movement between the atoms to intensify, so the vibration intensity increases. At the same time, under the action of pressure, N2O4 increases the IR activity in the high‐frequency region and reduces the IR activity in the low‐frequency region. [ABSTRACT FROM AUTHOR]

The effects of pressure on the lattice parameters, electronic properties and elastic properties of Sb2S3 under 0–30 GPa are studied by first‐principles calculation. The calculated results of structural parameters of generalized gradient approximation (GGA)‐Perdew–Burke–Ernzerhof (PBE) are less than 3% different from the previous experimental values. With the increase of pressure, the bandgap of Sb2S3 becomes smaller and smaller. At a pressure of 35 GPa, the conduction band coincides with the valence band. Metallization will occur. The Poisson's ratio results show that the Poisson's ratio of Sb2S3 crystal is 0.2892 at 10 GPa. When the pressure increases to 30 GPa, the mechanical stability criterion is no longer satisfied, and the mechanical properties will be unstable. At atmospheric pressure, there is no virtual screen in the phonon dispersion spectrum of Sb2S3. At 30 GPa, the phonon appears virtual screen and the structure is unstable. This is consistent with the results of the previous mechanical stability calculation. Finally, the wave velocity and anisotropy of Sb2S3 are calculated by its elastic coefficients. All the conclusions, herein, can provide a theoretical basis for the future study of Sb2S3 under high pressure. So, it is necessary to study the skills of Sb2S3 under high pressure. [ABSTRACT FROM AUTHOR]

The effects of vacancy concentration and Al substitution on the structural, electronic, and elastic properties of Nb5Si3 are studied using first‐principles calculations. The formation energy, elastic modulus, and electronic properties of three different Nb vacancies in Nb5Si3 are discussed in detail. With the increase in vacancy concentration, the obtained shear modulus, Young's modulus, and hardness of Nb vacancy decrease, which are lower than those of pristine Nb5Si3. The bulk modulus/shear modulus (B/G) ratio increases with the increase in Nb vacancy concentration. However, these vacancies result in the transition from brittleness to ductility, and Nb5Si3 with 5% vacancy concentration exhibits ductile behavior. The calculation of electronic structure shows that these Nb vacancies change the local hybridization between Nb and Nb atoms. As the concentration increases, the position of the peak moves toward lower energy. It is predicted that vacancies can improve the ductility behavior of Nb5Si3. [ABSTRACT FROM AUTHOR]

Herein, the pressure dependence of the structural, mechanical, and electronic properties is investigated for Fe2Si, FeSi, Fe3Si, α‐FeSi2, β‐FeSi2, Fe5Si3, and Fe11Si5 in the pressure range of 0–100 GPa based on density functional theory. The calculated lattice constants are in good agreement with the experimental results. The order of the thermodynamic stability of the seven structures is FeSi > Fe5Si3 > Fe2Si > β‐FeSi2 > Fe11Si5 > α‐FeSi2 > Fe3Si. The electronic properties are analyzed including density of states and band structures. The mechanical properties of FeSi, Fe2Si, Fe5Si3, α‐FeSi2, and β‐FeSi2 are studied thoroughly: The elastic constants are obtained under different pressures; the mechanical stability under the considered pressures is evaluated by the stability criteria. The results show that FeSi, Fe5Si3, and β‐FeSi2 are mechanically stable at pressures from 0 to 100 GPa; Fe2Si is unstable under compression; and α‐FeSi2 is unstable in the range of 60–100 GPa. The values of B, G, and E are calculated, which indicate that the ability to resist deformation of the material increases with the increase in pressure. The B/G values are calculated, suggesting that both Fe5Si3 and Fe2Si are ductile materials; the brittle–tough transition is observed in FeSi, α‐FeSi2, and β‐FeSi2. [ABSTRACT FROM AUTHOR]

Herein, the pressure dependence of the structure, electronic properties, mechanical stability, elastic properties, and Debye temperature of (α, β, γ)‐Nb5Si3 is investigated using the GGA‐PW91 functional. The results show that the pressure has a clear effect on the mechanical and electronic properties of (α, β, γ)‐Nb5Si3. The obtained structural and mechanical parameters agree well with the experiments and theoretical values at zero pressure. All these parameters linearly increase with the pressure. In particular, within the range of 25–100 GPa, the ductility of α‐Nb5Si3 increases with the pressure, indicating that the pressure can improve ductility. The anisotropy AU and AT values of Nb5Si3 increase with the increasing pressure, and it is clear that Nb5Si3 is an anisotropic material. The density of states (DOS) shows that the covalent properties of α‐Nb5Si3 are enhanced. The total density of states (TDOS) shape curve shows that the height of this peak decreases with the increasing pressure. The position of the peak shifts to lower energy. The Fermi level moves down with the pressure increases. [ABSTRACT FROM AUTHOR]

Herein, first‐principles calculations with density functional theory are used to investigate the structural, mechanical, and electronic properties of Fe–Si–Ti alloys, aiming to study the effects of Si and Fe in titanium alloys. The calculated lattice parameters are in good agreement with previous data. Alloying with Si/Fe can produce more brittle/ductile materials, due to the weaker/stronger metallic bonds. Furthermore, the effect of alloying with Si and Fe on the anisotropic properties is negligible. The increasing range of Debye temperatures by alloying with Si is greater than that by alloying with Fe. The capacity of Si to enhance the interatomic bonding force is greater than that of Fe due to the stronger covalent bonds. Similarly, the charge density reflects that the capacity of Si to enhance the interatomic bonding force is better than that of Fe for titanium alloys. In addition, the metallic conductivity of these alloys is verified, with there being no gaps at the Fermi level. The localization of electrons in the SiTi alloy is observed to be relatively strong around the Fermi level. In addition, the amplitude of the top of the valence band and the bottom of the conduction band is smooth, showing great effective mass. [ABSTRACT FROM AUTHOR]

Due to its p-type conductivity, CuAlO2 has been widely studied. However, the conductivity of p-type CuAlO2 is much lower than that of n-type, which limits its applications. We used the generalized gradient approximation and hybrid functional B3LYP to study the effects of chalcogen substitution on the electronic properties and chemical bondings of delafossite CuAlO2. The calculated results show that the doping of chalcogen (S, Se, and Te) substituting for O is thermodynamically stable. The calculated volumes, bandgaps, and valence-band widths of dopants have been detailedly discussed, indicating that the volumes and valence-band widths are increased, but the bandgaps are decreased. The density of states and charge-density distribution ranges have been analyzed, suggesting that chalcogen substitution is a good way to design new p-type Cu-based TCOs. [ABSTRACT FROM AUTHOR]

Due to its p-type conductivity, CuAlO2 has been widely studied. However, the conductivity of p-type CuAlO2 is much lower than that of n-type, which limits its applications. We used the generalized gradient approximation and hybrid functional B3LYP to study the effects of chalcogen substitution on the electronic properties and chemical bondings of delafossite CuAlO2. The calculated results show that the doping of chalcogen (S, Se, and Te) substituting for O is thermodynamically stable. The calculated volumes, bandgaps, and valence-band widths of dopants have been detailedly discussed, indicating that the volumes and valence-band widths are increased, but the bandgaps are decreased. The density of states and charge-density distribution ranges have been analyzed, suggesting that chalcogen substitution is a good way to design new p-type Cu-based TCOs. [ABSTRACT FROM AUTHOR]

Structural, elastic, mechanical, electronic properties, and dispersion of optical functions of hexagonal ZnTiO3 have been investigated from first-principles within density-functional theory (DFT) using the norm-conserving pseudopotentials method, within the generalized gradient approximation (GGA) to the exchange-correlation functional. The calculated structural parameters agree with the available experimental and theoretical results. The elastic constants, bulk modulus, shear modulus, Young's modulus, Poisson's ratio, and Lamé's constants as well as mechanical stability have been studied, indicating that hexagonal ZnTiO3 is mechanically stable, anisotropic, and ductile. The electronic structure and chemical bonding of hexagonal ZnTiO3 have been analyzed according to the calculated energy band structure, density of states (DOS), and charge populations. Dispersion of optical functions is shown and analyzed, including the complex dielectric function, refractive index, extinction coefficient, reflectivity, absorption coefficient, loss function, and optical conductivity. [ABSTRACT FROM AUTHOR]

Structural, elastic, mechanical, electronic properties, and dispersion of optical functions of hexagonal ZnTiO3 have been investigated from first-principles within density-functional theory (DFT) using the norm-conserving pseudopotentials method, within the generalized gradient approximation (GGA) to the exchange-correlation functional. The calculated structural parameters agree with the available experimental and theoretical results. The elastic constants, bulk modulus, shear modulus, Young's modulus, Poisson's ratio, and Lamé's constants as well as mechanical stability have been studied, indicating that hexagonal ZnTiO3 is mechanically stable, anisotropic, and ductile. The electronic structure and chemical bonding of hexagonal ZnTiO3 have been analyzed according to the calculated energy band structure, density of states (DOS), and charge populations. Dispersion of optical functions is shown and analyzed, including the complex dielectric function, refractive index, extinction coefficient, reflectivity, absorption coefficient, loss function, and optical conductivity. [ABSTRACT FROM AUTHOR]

In this article, the properties of Cs2Pb2O3 have been investigated using the first‐principles method. It covers the relevant structural, stability, electronic properties, conductivity, and optical properties. The phonon spectra and elastic properties analysis show the stability of Cs2Pb2O3, band structure, density of states, charge density diagram, and bond populations are analyzed to show the electronic structure of the system more clearly. The calculated results indicate that considering spin‐orbit coupling (SOC) will reduce the band gap. The charge density diagram and bond populations indicate that the Cs–O bond is mainly ionic and the Pb–O bond is mainly covalent and partially ionic. The analysis of optical properties indicates good transparency, and the calculated hole mobility is 10.88 cm2 V−1 s−1, suggesting that it is a promising p‐type conductive oxide. [ABSTRACT FROM AUTHOR]