The European Physical Journal B最新文献

The escalating global climate crisis, driven by greenhouse gas emissions, necessitates advanced sustainable energy technologies, including hydrogen production, CO₂ photoreduction, and waste heat recovery. This study explores the vacancy-ordered double perovskites Rb₂MBr₆ (M = W⁴⁺: 5d², Re⁴⁺: 5d³, Os⁴⁺: 5d⁴, Ru⁴⁺: 4d⁴) as promising materials for these applications, leveraging their enhanced stability and tunable properties. Employing density functional theory (DFT) with spin–orbit coupling (SOC) and the Tran-Blaha modified Becke-Johnson (TB-mBJ) potential in the WIEN2k framework, we investigate structural stability, electronic band structures, optical absorption, photocatalytic reactivity, and thermoelectric performance. Results reveal cubic Fm-3m structures with lattice constants of 10.36–10.97 Å, negative formation energies (−1.26 to −3.60 eV), and mechanical ductility (B/G > 1.75), confirming thermodynamic and structural robustness. Band gaps range from 1.54 eV (Rb₂RuBr₆) to 2.97 eV (Rb₂WBr₆), with half-metallic ferromagnetic behavior enhancing spintronic potential. Optical absorption coefficients (4.32–21 × 10⁵ cm⁻¹) and low exciton binding energies (18.3–27.3 meV) support efficient photocatalysis, with Rb₂WBr₆ showing balanced band edges for water splitting (E_VB = 1.48 V, E_CB = −1.48 V vs. NHE). Thermoelectric figures of merit (ZT) reach 1.325 (Rb₂ReBr₆) at 300 K, declining to 1.275 at 1000 K, surpassing Bi₂Te₃. These findings establish Rb₂MBr₆ as a versatile platform for clean energy technologies, with future experimental validation poised to accelerate their deployment.

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As the search for high-performance, stable and eco-friendly photovoltaic materials intensifies, oxide perovskites have achieved substantial devotion for solar cell and optoelectronic applications. Their robust crystal frameworks, tunable electronic properties and non-toxic composition distinguish them from halide-based counterparts. A detailed analysis of the structural, mechanical, electronic and optical behavior of CoAlO₃ and CrAlO₃ perovskites was carried out using density functional theory (DFT). Both compounds implement a cubic symmetry with optimised lattice constants confirming their stability. CoAlO₃ and CrAlO₃ exhibit promise for optoelectronic applications; however, the wider band gap of CoAlO₃ (2.17 eV) renders it more appropriate for UV/visible photodetectors and LEDs, while the smaller band gap of CrAlO₃ (1.81 eV) aligns more closely with the optimal range for solar energy harvesting. Optical studies show high visible–UV absorption, low energy loss and substantial optical conductivity, ensuring efficient light–matter interaction. Mechanical analysis indicates a bulk modulus (B) of 174.8 GPa for CoAlO₃ and 42.13 GPa for CrAlO₃ with shear moduli (G) of 65.34 GPa and 36.98 GPa, respectively. The Pugh’s ratio (B/G) for CoAlO₃ is 2.67, indicating ductility, whereas CrAlO₃, with a ratio of 1.13, clearly exhibits brittleness. The combination of favourable optical and structural properties, along with eco-safe composition, suggests CoAlO₃ and CrAlO₃ as strong contenders for next-generation solar cells and optoelectronics.

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To address the issue of excessive use of fossil fuels, which are causing environmental pollution; researchers are continuously exploring for alternative energy sources. Although a greater no of renewable energy production devices has been explored but storage is still a big problem. Supercapacitor are the well-known and effective energy storage device. Here, rGO was combined with spinel-based metal oxide to synthesize a BaFe₂O₄/rGO electrode using hydrothermal procedure. The material exhibited significant surface zone, as determined through Brunauer–Emmett–Teller (BET) study. Scanning electron microscopy (SEM) confirmed that BaFe₂O₄ was uniformly and tightly distributed over the rGO surface. The synthesized electrode displayed high C_s of 1498.673 F g⁻¹, an Ed of 54.693 Wh kg⁻¹ and Pd of 256.3 W kg⁻¹ at jd of 1 A g⁻¹. Moreover, Nyquist graph shows lowest solution impedance (R_s) of 0.75 Ω, signifying excellent electrical conductivity. The material also maintained its performance after 5000th cycles, demonstrating impressive stability. This study highlights the innovative design of BaFe₂O₄/rGO nanocomposite, where incorporation of rGO effectively addresses poor conductivity of pristine BaFe₂O₄, thereby enhancing its electrochemical performance for supercapacitor (SCs) applications.

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Designing chaotic systems based on the physical mechanism to generate controllable chaotic attractors with specific structures is instrumental in advancing our understanding of chaotic dynamics and promoting engineering applications. By introducing the oscillating Gaussian potential, a novel Duffing system is developed, in which the stability of equilibrium points undergoes periodic alternation. This alternation effectively increases the total number of both stable and unstable points, thereby leading to the generation of additional scrolls in the chaotic attractor. Leveraging the physical interpretability of the Duffing framework, the number of scrolls can be controlled by tuning key parameters, including the potential difference, oscillation amplitude and frequency, and damping coefficient, as confirmed by bifurcation analysis. The Poincaré maps exhibit a multi-scroll structure that evolves synchronously with the potential well oscillation, demonstrating the unique dynamic behavior induced by alternating equilibrium points. In this regime, particles are successively attracted and repelled as the equilibrium points periodically switch between stable and unstable states. The system also exhibits both homogeneous and heterogeneous multistability. Finally, our results were verified through hardware experiments based on microcontrollers.

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In this work, we present a comprehensive first-principles investigation of a new family of Pt-based half-Heusler alloys with the general formula PtYZ (Y = V, Nb, Ta; Z = Al, Ga, In), all satisfying the 18-valence-electron rule and exhibiting semiconducting behavior. The alloys preferentially crystallize in the type-III structure, fulfilling the Born–Huang mechanical stability criteria, with Pugh’s and Poisson’s ratios indicating ductile and predominantly ionic bonding. Phonon dispersion calculations, performed for representative compounds, further confirm their dynamical stability. The HSE06 hybrid functional significantly refines the electronic description, yielding band gaps from −0.05 to −1.0 eV and revealing a clear trend of increasing d-orbital delocalization from 3d (V) to 5d (Ta) elements. Optical simulations show strong absorption across the visible and ultraviolet regions, with a redshift toward the visible–NIR range for V-based alloys. The combination of mechanical robustness, tunable band gaps, and favorable optical absorption highlights these Pt-based half-Heusler alloys as promising candidates for solar cell and optoelectronic applications, expanding the design space of functional semiconducting Heusler compounds and providing valuable guidance for future experimental studies.

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We investigated the magneto-electronic, structural, mechanical, and thermal properties of a novel family of Ti₂RhX (X = Si, Ge, and Sn) ternary Heusler alloys using the full-potential linearized augmented plane wave (FP-LAPW) method as implemented in the Wien2k code. The results reveal that all compounds are ferrimagnetic with negative formation energies, indicating thermodynamic stability and feasibility for experimental synthesis. Electronic band structure and density of states calculations confirm their half-metallic ferrimagnetic character, with spin polarization near the Fermi level and minority-spin band gaps of approximately 0.1–0.3 eV. Mechanical analysis based on elastic constants shows that these materials are ductile, with high Young’s modulus and Pugh’s ratio exceeding 1.75. Thermal properties were examined using the quasi-harmonic Debye model and non-equilibrium Gibbs functions, yielding temperature- and pressure-dependent trends in heat capacity, bulk modulus, Debye temperature, and thermal expansion coefficients. These findings suggest that Ti₂RhX alloys are promising candidates for spintronic applications and pave the way for further theoretical and experimental investigations.

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We extensively studied Ti2RhX (X = Si, Ge, Sn) Heusler alloys using advanced FP-LAPW methods, unveiling their ferrimagnetic nature, stiffness, and half-metallic ferrimagnetic behavior. Our research also probed their thermal properties and provided a foundational understanding for potential applications.