The European Physical Journal B最新文献

This study investigates the physical properties of the novel mixed metal oxide Mg₃ZnO₄, emphasizing its potential in optoelectronic manufacturing. We provide a comprehensive analysis of its structural, optoelectronic, mechanical, and thermodynamic characteristics, focusing on the ternary compound, which crystallizes in a rocksalt phase similar to the mineral Caswellsilverite. Using advanced density functional theory (DFT) and the Full-Potential Linearized Augmented Plane Wave (FP-LAPW) method within the WIEN2k package, we predict the material’s properties in detail. Our structural analysis confirms the stability of Mg₃ZnO₄ in the cubic Pm3̅m space group, revealing key crystallographic parameters. The electronic structure calculations indicate a well-defined energy band gap, confirming its semiconducting nature and suitability for optoelectronic applications. Optical properties, including the dielectric function, absorption, and reflection spectra, demonstrate significant light interaction, highlighting the material’s potential for UV photodetectors and photovoltaic solar cells. The investigation of elastic properties provides critical insights into the mechanical strength and durability of Mg₃ZnO₄, further supporting its viability for demanding applications. Additionally, our thermodynamic analysis reveals the material’s behavior under varying environmental conditions, reinforcing its potential in high-performance optoelectronic devices. These findings establish Mg₃ZnO₄ as a promising candidate for advanced thin-film solar cells and pave the way for future experimental and theoretical studies to explore its unique properties for innovative technological applications.

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Mass and energy rate (ER) data have been collected for a wide variety of dissipative systems from the biological, cultural, and cosmological realms. They range from 6 × 10^–25 kg and 3 × 10^–25 W for a synthetic, molecular engine to 1.5 × 10⁵³ kg and 10⁴⁸ W for the observable universe and, thus, span 78 mass and 73 ER orders of magnitude, respectively. The combination of (i) convergence of smaller systems (parts) to a larger system and (ii) scaling of ER as a function of mass with a power law constant β > 0 for groups of systems, explains why the ER and mass data points fall in a diagonal band in the double logarithmic ER vs. mass master plot. There appears to be an ER vs. mass limit, corresponding to an energy rate density (ERD = ER/mass) of around 10⁵ W/kg, separating stable, dissipative systems from unstable, “explosive” systems (atomic weapons, supernova, etc.) in all realms. This limit is probably the result of a balance between the energy flow through a system, resulting in increased temperature and pressure, and the strength of the system’s structure and boundary. ERD has been proposed as a metric for the development of the complexity of dissipative systems over deep time Chaisson (Cosmic evolution; The rise of complexity in nature. Harvard University Press, Cambridge, 2002), Chaisson (Sci World J 384912, 2014). Thus, the observed ERD threshold of 10⁵ W/kg may correspond to a maximum of complexity. Several ways to further increase complexity while circumventing this ERD limit are proposed.

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The study of renewable energy sources is currently an urgent problem. Such materials are produced by constructing phase diagrams or by cation–anionic substitution of an existing material. From this point of view, the formation of a solid solution (CdSe)_1–x(As₂S₃)x can be due to anionic substitution, which is capable of creating functional properties. In this regard, differential thermal analysis (DTA), X-ray diffraction (XRD), microstructural analysis (MSA), as well as measurements of microhardness and density were performed on solid solutions (CdSe)_1–x(As₂S₃)_x. The nature of the chemical interaction of CdSe with As₂S₃ was studied and it was established that the introduction of As₂S₃ into the composition of CdSe leads to the formation of solid solutions. Moreover, it has been found that solid solutions are formed up to 3 mol% concentration of As₂S₃. The temperature dependence of the electrical conductivity and thermo-EMF of (CdSe)_1–x(As₂S₃)_x (x = 0.01; 0.02; 0.03) solid solutions has been studied. It has been established that the obtained alloys of the solid solution (CdSe)_1–x(As₂S₃)_x (x = (x = 0.01; 0.02; 0.03) are semiconductors of medium resistance. When introducing high-resistance samples of 1; 2 and 3 mol. % As₂S₃ into the composition of CdSe, the specific resistance of the alloys increases depending on the composition, and the conductivity decreases accordingly. For alloys of solid solutions (CdSe)_1–x(As₂S₃)_x, in the composition of 0.3; 0.6; 0.8 and 1.0 mol % As₂S₃, the spectral distribution of the photocurrent was studied. Samples containing 0.3; 0.6; 0.8 and 1.0 mol% As₂S₃ are photosensitive materials capable of operating in the wavelength range of 0.4–1.1 μm.

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The article applies the thermodynamic theory built by statistical moment method (SMM) to determine numerically the temperature and pressure dependences of the thermal expansion coefficient, the heat capacity constant pressure and the Gruneisen parameter of MgSiO₃ perovskite in the temperature range from 0 to 4000 K and in the pressure range from 0 to 135 GPa. Our SMM numerical results for MgSiO₃ perovskite are compared with that for CaSiO₃ perovskite, experimental data and results calculated by other methods. Our SMM numerical results are new and predictive of experimental results. This is the first application of SMM to study the thermodynamic characteristics of cubic MgSiO₃ perovskite under extreme conditions of the Earth’s lower mantle.

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Based on the Weyl–Bogoliubov-de Gennes equation, we investigate the impact of biaxial strain on the Josephson supercurrent in a 2D Weyl semimetal Josephson junction, where the biaxial strain is induced by a piezoelectric film. It is shown that the current phase relation can be attenuated and non-monotonically modulated by the transverse and the longitudinal strain strength, respectively. When both are present, the subgap Andreev bound levels and the resulting Josephson supercurrent are sensitive to the potential energy and the length in the weak link region and the gate voltage (biaxial strain), and an enhancement or weakening of the supercurrent by shifting the Weyl nodes without requiring a magnetic or Zeeman term is induced. It is also revealed that the gate voltage (strain) can cause a supercurrent switch, where the cutoff gate voltage depends on the potential energy in the weak link region. The research also explores the temperature dependence of the supercurrent, noting a monotonic decrease and a logistic-like function with increasing temperature due to the thermal effect on subgap Andreev bound levels. The findings of this study are significant for the understanding of superconducting electronics in 2D Weyl semimetal and offering a new avenue for designing strain tunable quantum devices with all-electrical control.

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Random initial conditions are extensively used in sociophysics models. However, hierarchically organized setups were recently used, producing interesting results which are not seen in the random case. We deepen those previous works by studying an opinion dynamics model where there are two initial opposing ideological groups and a third emergent party. We assume the same amount of adherents for each initial party and focus on varying the degree of their structure. Here we introduce a new approach that uses ternary diagrams as a tool to visualize phenomena that are otherwise hidden in conventional observables (e.g., parties’ probability of winning). We were able, through these diagrams, to unveil the presence of adherence quantization when the system is highly structured. We deduce an analytical expression finding an excellent agreement with simulated results. The explanation for this quantization is based on a new type of interaction, not between individuals, but among groups of individuals.

Superconducting materials' crystal lattices and electronic structures have fascinated the materials science research group. In the present work, we have investigated and discussed the structural, electronic, and elastic properties of single-crystal YBa₂Cu₃O₇ under pressure up to 20 GPa using the first principal calculations based on the density functional theory (DFT). The results showed that this compound's calculated lattice parameters under zero pressure agree with the experimental results. The calculated band structures and the DOS show that YBa₂Cu₃O₇ is metallic. The width of the electronic band increases with pressure, due to the increased overlap of the orbitals. The pressure-dependent single-crystal elastic constants ensure mechanical stability. The calculated value of Poisson’s ratio (n ~ 0.32) suggests that the compound is ductile and that the metallic contribution dominates our material. The variations of anisotropy indices show a monotonic dependence on pressure, indicating that the studied material becomes elastically anisotropic while increasing the pressure. Debye temperature and sound velocity were calculated from the elastic constants and crystal density. They increase systematically with pressure. Our material also appears to have high Debye temperatures, indicating that it may have high thermal conductivity. Finally, we have calculated and discussed the optical properties at ambient pressure (dielectric function, absorption, refractive index, conductivity, loss function, and reflectivity) for both polarization directions [100] and [001].

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