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This study examines the physical characteristics of Co2Te3O8 in the spiroffite structure using an ab initio approach. The optimization of the Co2Te3O8 structure, in both nonmagnetic and magnetic states, indicates that the magnetic state is more stable than the non-magnetic one. Thermodynamic properties under various temperatures and pressures, calculated via the quasi-harmonic approximation, reveal that the specific heat capacity of spiroffite Co2Te3O8 conforms to the Debye model and satisfies the Dulong and Petit limits. The electrical, magnetic, and optical properties of Co2Te3O8 are investigated using the GGA and TB-mBJ approximations. Analysis of the density of states and the band structure indicates that spiroffite Co2Te3O8 exhibits semiconductor characteristics in both the spin up and spin down channels. The study is extended to apply hydrostatic pressure to assess the electronic and magnetic properties of both unstrained and strained structures of Co2Te3O8. It is found that within the investigated pressure range (0–15 GPa), no structural changes are observed. Furthermore, a slight decrease in the spin up gap is noted, while no appreciable changes are observed in the spin down gap. Moreover, the investigation into the spin-polarized thermoelectric properties of the material reveals that it achieves a high figure of merit, approximately 0.99, across broad temperature spectra. This performance highlights its suitability as a candidate for thermoelectric power generation. Finally, optical properties calculations on spiroffite Co2Te3O8 reveal efficient absorption in the ultraviolet region. [ABSTRACT FROM AUTHOR]

This study examines the physical characteristics of Co2Te3O8 in the spiroffite structure using an ab initio approach. The optimization of the Co2Te3O8 structure, in both nonmagnetic and magnetic states, indicates that the magnetic state is more stable than the non-magnetic one. Thermodynamic properties under various temperatures and pressures, calculated via the quasi-harmonic approximation, reveal that the specific heat capacity of spiroffite Co2Te3O8 conforms to the Debye model and satisfies the Dulong and Petit limits. The electrical, magnetic, and optical properties of Co2Te3O8 are investigated using the GGA and TB-mBJ approximations. Analysis of the density of states and the band structure indicates that spiroffite Co2Te3O8 exhibits semiconductor characteristics in both the spin up and spin down channels. The study is extended to apply hydrostatic pressure to assess the electronic and magnetic properties of both unstrained and strained structures of Co2Te3O8. It is found that within the investigated pressure range (0–15 GPa), no structural changes are observed. Furthermore, a slight decrease in the spin up gap is noted, while no appreciable changes are observed in the spin down gap. Moreover, the investigation into the spin-polarized thermoelectric properties of the material reveals that it achieves a high figure of merit, approximately 0.99, across broad temperature spectra. This performance highlights its suitability as a candidate for thermoelectric power generation. Finally, optical properties calculations on spiroffite Co2Te3O8 reveal efficient absorption in the ultraviolet region. [ABSTRACT FROM AUTHOR]

Technological development cannot take place without a deep knowledge of materials and their physical properties. Complex oxides constitute a family of materials characterized by specific characteristics prompting them for potential technological applications. The results of a theoretical study related to the structural, thermodynamic, electronic, optical, and magnetic properties of the Dy2Be2GeO7 complex oxide are presented. The current study is accomplished using the "Full Potential (FP) Linearized (L) Augmented Plane Wave Plus Local Orbitals (APW + lo)" formalism as incorporated in the WIEN2k computational code in the "density functional theory" framework. To approximate the exchange and correlation effects, the PBE-GGA formalism of the "generalized gradient approximation" is used. Furthermore, "Tran-Blaha modified Becke–Johnson potential" is used to better describe the electronic structure. The equilibrium structural parameters are in good agreement with the corresponding measured data reported in the literature. The thermodynamic properties of the title compounds are explored via the quasi-harmonic approximation over temperature and pressure ranges from 0 to 700 K and 0 to 10 GPa, respectively. The electronic properties are determined with spin-polarized inclusions. Finally, the optical properties are examined with a detailed discussion of different optical parameters, including dielectric function, absorption coefficient, optical conductivity, reflectivity, and refractive index spectra. The Dy2Be2GeO7 complex oxide with a non-centrosymmetric tetragonal structure shows a negative birefringent, therefore it is a possible candidate for applying to the birefringent field and nonlinear optical process. To our best knowledge, the current study is the first effort to explore the physical characteristics of the considered complex oxide. [ABSTRACT FROM AUTHOR]