Investigation of Iron-based double perovskite oxides on the magnetic phase stability, mechanical, electronic and optical properties via first-principles calculation

Six similar compounds Ba2MNO6 (M = Y, Sc; N = Nb, V, Ta) are obtained by elemental substitution of three double perovskite oxides Ba2YNbO6, Ba2YTaO6 and Ba2ScTaO6 that have been synthesized experimentally. The stability, mechanical, electronic properties and thermal conductivity of double perovskite oxides Ba2MNO6 (M = Y, Sc; N = Nb, V, Ta) are explored using the ab-initio methods. The negative formation enthalpy and positive phonon frequencies confirm double perovskite oxides Ba2MNO6 have thermodynamic and kinetic stability. Ba2MNO6 (M = Y, Sc; N = Nb, V, Ta) are found to be anisotropic and exhibit brittle behavior. Electronic structure calculations confirm that these double perovskite oxides are direct bandgap semiconductors, with bandgaps of 3.106 eV, 1.554 eV, 3.451 eV, 2.877 eV, 1.444 eV and 3.203 eV, respectively. Electronic effective mass and hole effective mass have small absolute values suggests that the carrier mobility in these compounds may be higher and have a better potential for photovoltaic transformation. Comparing with most semiconductor materials, these double perovskite oxides have a high melting point of approximately 2000 K. The lattice thermal conductivity of all compounds decreases as the temperature increases, which is consistent with the general law of thermal conduction. The minimum thermal conductivity demonstrates that the double perovskite oxides could be superior in electromechanical and thermoelectric applications. Low lattice thermal conductivity facilitates can improve thermoelectric ZT values.

The structural, stability, electronic, optical and thermodynamic properties of Ba2AsXO6（X = V, Nb, Ta）double perovskite oxides: A First-Principles study

First-principles investigation of structural, mechanical and electronic properties for Cu–Ti intermetallics

The main objective of this work is to make a detailed study on a new class of half heuslers which possess a 19 valence electron and which are sought for perpetually because of their thermoelectric performances. The mechanical, electronic structures, optical, and electrical transport properties are studied using full potential linearized augmented plane wave (LAPW) + local orbitals (lo) scheme, in the framework of density functional theory (DFT) with generalized gradient approximation (GGA) for the purpose of exchange correlation energy functional. The electronic structure is treated by the TB‐mBJ exchange‐correlation potentials. The independent elastic constants and the related mechanical properties are investigated. From the energy bands and density of states it is observed that the 3d‐states of Nb, Ta, and Rh atoms contribute mainly to the conduction band, which results in increase in electrical and thermal conductivity of NbRhSb and TaRhSb . The optical constants as the dielectric function, refractive index, optical reflectivity, and absorption coefficient were calculated and discussed in detail. The dependence of Seebeck coefficient, electrical conductivity, and power factor on the Fermi level is investigated.

This study presents a comprehensive investigation into the intrinsic properties of RNi4P12 (where R = Sm, Eu) filled skutterudite, employing the full-potential linearized augmented plane wave method within density functional theory (DFT) simulations using the WIEN2k framework. Structural, phonon stability, mechanical, electronic, magnetic, transport, thermal, and optical properties are thoroughly explored to provide a holistic understanding of these materials. Initially, the structural stability of SmNi4P12 and EuNi4P12 is rigorously evaluated through ground-state energy calculations obtained from structural optimizations, revealing a preference for a stable ferromagnetic phase over competing antiferromagnetic and non-magnetic phases. Electronic properties are further investigated using a combination of computational schemes, including Generalized Gradient Approximation (GGA) and Trans-Bhalla modified Becke Johnson (TB-mBJ), effectively handling the f-electrons. Both approximations reveal intriguing metallic behavior in both spin-up and spin-down channels. The focus is on Ni-P-based filled skutterudite, featuring localized 4f and 5d-electrons, which exhibit dense energy bands near the Fermi energy, originating from rare earth and Ni-atoms. The dense density of states near the Fermi energy suggests suitability for thermoelectric applications. Additionally, spin-polarized band structures unveil significant net magnetism, indicating potential applications in spintronics. Elastic parameters are estimated using the Voigt-Reuss-Hill approximation, with elastic stability crucial for practical applications, characterized by brittleness indicating the compounds’ ability to deform without fracturing under stress. Finally, transport and thermal properties are analyzed, providing insights into conductivity and heat dissipation characteristics. Optical constants, including dielectric function, optical reflectivity, refractive index, electron energy loss, and optical conductivity, are calculated for photon energy radiation. Overall, this study offers a comprehensive understanding of the multifaceted properties of SmNi4P12 and EuNi4P12-filled skutterudite, laying the groundwork for their potential applications in various fields.

Chalcogenides are chemical compounds with at least one of the following three chemical elements: Sulfur (S), Selenium (Sn), and Tellurium (Te). As opposed to other materials, chalcogenide atomic arrangement can quickly and reversibly inter-change between crystalline, amorphous and liquid phases. Therefore they are also called phase change materials. As a results, chalcogenide thermal, optical, structural, electronic, electrical properties change pronouncedly and significantly with the phase they are in, leading to a host of different applications in different areas. The noticeable optical reflectivity difference between crystalline and amorphous phases has allowed optical storage devices to be made. Their very high thermal conductivity and heat fusion provided remarkable benefits in the frame of thermal energy storage for heating and cooling in residential and commercial buildings. The outstanding resistivity difference between crystalline and amorphous phases led to a significant improvement of solid state storage devices from the power consumption to the re-writability to say nothing of the shrinkability. This work focuses on a better understanding from a simulative stand point of the electronic, vibrational and optical properties for the crystalline phases (hexagonal and faced-centered cubic). The electronic properties are calculated implementing the density functional theory combined with pseudo-potentials, plane waves and the local density approximation. The phonon properties are computed using the density functional perturbation theory. The phonon dispersion and spectrum are calculated using the density functional perturbation theory. As it relates to the optical constants, the real part dielectric function is calculated through the Drude-Lorentz expression. The imaginary part results from the real part through the Kramers-Kronig transformation. The refractive index, the extinctive and absorption coefficients are analytically calculated from the dielectric function. The transmission and reflection coefficients are calculated using the Fresnel equations. All calculated optical constants compare well the experimental ones.

Theoretical prediction of the elastic, electronic and optical properties of the filled tetrahedral semiconductor α-LiMgSb

The ab initio calculations of the structural phase stability, magnetic phase stability, and electronic and magnetic properties of the FmP binary monopnictides and the half-metallic ferromagnetic properties of their Fm1−xVxP (for x = 0.25, 0.50, 0.75, and 1)-doped alloys have been assured through the spin-polarized density functional theory (DFT), and they are performed by employing the full-potential linearized augmented plane waves plus local orbitals (FP-L/APW + lo) method that is implemented in the WIEN2k package. The exchange and correlation potential is parameterized by the generated gradient approximation (GGA) of Perdew-Burke-Ernzerhof (PBE) scheme. According to the studies of the magnetic phase stability, the fermium monopnictides (FmP) have a paramagnetic regime, while the ferromagnetic behavior appears when we dope this compound with vanadium. Through the ferromagnetic character of all Fm1−xVxP alloys, the spin-polarized band structures and densities of states exhibit a nearly half-metallic character of Fm0.75V0.25P alloy, whereas Fm0.50V0.50P, Fm0.25V0.75P, and VP compounds showed metallic character. Moreover, the total magnetic moment of the three ternary alloys is mainly contributed by Fm and V elements, where the p-d hybridization reduces the atomic magnetic moment of V element from its free space charge and produces feeble magnetic moments on the nonmagnetic P sites.

Multi-functional lead-free Ba2XSbO6 (X = Al, Ga) double perovskites with direct bandgaps for photocatalytic and thermoelectric applications: A first principles study

Optoelectronic and mechanical properties of gallium arsenide alloys: Based on density functional theory

First-principles study of hypothetical boron crystals: Bn(n = 13, 14, 15)

A comprehensive investigation of structural and magnetic phase stability, electronic, magnetic and thermoelectric properties of Co2FeZ (Z = Al, Ga, Si, Ge, S, Se and Te) Full Heusler alloys

A first principle study of phase stability, electronic structure and magnetic properties for Co2−xCrxMnAl Heusler alloys

By combining theoretical density functional theory (DFT) and experimental studies, structural and magnetic phase stabilities and electronic structural, elastic, and vibrational properties of the Laves-phase compound ${\mathrm{NbMn}}_{2}$ have been investigated for the C14, C15, and C36 crystal structures. At low temperatures C14 is the ground-state structure, with ferromagnetic and antiferromagnetic orderings being degenerate in energy. The degenerate spin configurations result in a rather large electronic density of states at Fermi energy for all magnetic cases, even for the spin-polarized DFT calculations. Based on the DFT-derived phonon dispersions and densities of states, temperature-dependent free energies were derived for the ferromagnetic and antiferromagnetic C14 phase, demonstrating that the spin-configuration degeneracy possibly exists up to finite temperatures. The heat of formation ${\mathrm{\ensuremath{\Delta}}}_{298}{H}^{0}=\ensuremath{-}45.05\ifmmode\pm\else\textpm\fi{}3.64\phantom{\rule{0.16em}{0ex}}\mathrm{kJ}\phantom{\rule{0.16em}{0ex}}{(\mathrm{mol}\phantom{\rule{0.16em}{0ex}}\mathrm{f}.\mathrm{u}.\phantom{\rule{0.16em}{0ex}}{\mathrm{NbMn}}_{2})}^{\ensuremath{-}1}$ was extracted from drop isoperibolic calorimetry in a Ni bath. The DFT-derived enthalpy of formation of ${\mathrm{NbMn}}_{2}$ is in good agreement with the calorimetric measurements. Second-order elastic constants for ${\mathrm{NbMn}}_{2}$ as well as for related compounds were calculated.

First-principles calculations to investigate structural, electronic, thermoelectric, and optical properties of heavy thallium perovskite TlPbX3 (X = Cl, Br, I)