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This study employs a first-principles approach to comprehensively examine the structural, electronic, optical, and magnetic properties of the thermodynamically stable scintillating double perovskite halides A 2 N a T a X 6 ( A = C s , R b ; X = C l , B r , I ). The dynamic stability of these materials were explained based on deduced phonon properties. Our analysis reveals that these compounds exhibit intriguing electronic behavior with spin polarization, demonstrating half-metallicity. In spin-up, the band gap is found to be zero, while in spin-down, it falls within the range of 3 to 4 eV with the incorporation of DFT+U corrections. Notably, the optical properties assessment highlights the exceptional UV and high-energy absorption capabilities of A 2 N a T a I 6 , making it a promising candidate for scintillation applications in particle detection. This research sheds light on the unique and versatile properties of these materials, with implications for various technological and scientific applications. [ABSTRACT FROM AUTHOR]

The two-body leptonic decays of both light and heavy-charged mesons X l 2 ± are investigated in the first Born approximation in the presence of a monochromatic and circularly polarized laser field. As a result of using Volkov functions, the analytic study of these processes has brought a change in the parameters associated with each decay process. The decay width, lifetime, and branching ratio of each decay process are affected by increasing the classical parameter ξ of the meson. A comparison between the matter decay X l 2 + and that of the anti-matter X l 2 - in the presence of a circularly polarized laser wave, indicates that increasing laser field strength (increasing the classical parameter ξ ) can induce a slight dominance of matter over antimatter or vise versa. [ABSTRACT FROM AUTHOR]

The Full Potential Linearised Augmented Plane Wave method (FP-LAPW) is used to design the structural, elastic-mechanical, electronic, magnetic, and thermoelectric prop-erties of new cubic double perovskite oxides X 2 C e V O 6 (X = S r , B a) . The tolerance factor and elastic parameters show and ensure the stability and formation of both perovskites in the cubic phase. Additionally, the predicted mechanical constants show that X 2 C e V O 6 (X = S r , B a) behave as stable ductile materials. Then, spin-polarized calculations show ferromagnetic and half-metallic behavior for both compounds with a total magnetic moment equal to 1 μ β . Thermoelectric parameters of both materials show high power factor and n-type conductivity, due to the multiple oxidation states of Vanadium. Therefore, these results show that the proposed perovskites X 2 C e V O 6 (X = S r , B a) can be promising materials for spintronic and thermoelectric applications. [ABSTRACT FROM AUTHOR]

In the center of mass frame, we have investigated the process of Higgs-strahlung production in association with a pair of fermions, e + e - → f f ¯ H , at the leading order in the presence of an intense electromagnetic field with circular polarization. Our analytical calculations are based on the narrow width approximation, which is valid in the leading order as Γ Z / M Z = 2 % . We have considered only the initial particles inside the laser field as a first step. In the second part, we have embedded both initial and final particles in the laser field. We have analyzed the angular distribution of the produced Higgs boson as a function of the laser parameters in both cases. We have found that the order of magnitude of the differential cross section of both processes e + e - → μ + μ - H and e + e - → b b ¯ H is reduced more significantly in the case where both initial and final particles are embedded in the laser field. [ABSTRACT FROM AUTHOR]

Recent advancements and developments in photovoltaic materials have made significant progress owing to the search for efficient and sustainable energy sources. Although lead halide perovskites have demonstrated impressive performance in solar cell applications, they face challenges such as environmental instability and lead toxicity. This study investigates several physical properties of two lead-free double halide perovskites, Rb2CuAsBr6\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$Rb_{2}CuAsBr_{6}$$\end{document} and Rb2TlAsBr6\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$Rb_{2}TlAsBr_{6}$$\end{document}, and evaluates their potential for solar cell applications using density functional theory (DFT) within the Wien2k code and spectroscopic limited maximum efficiency (SLME) approach. The negative formation energy and Born criteria confirm the structural stability of both perovskites in the ideal cubic structure. Optoelectronic analyses reveal that Rb2TlAsBr6\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$Rb_{2}TlAsBr_{6}$$\end{document}, with a direct band gap of 1.51 eV, exhibits better photovoltaic characteristics compared to Rb2CuAsBr6\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$Rb_{2}CuAsBr_{6}$$\end{document}, which has an indirect band gap of 0.60 eV. Additionally, the SLME analysis shows that Rb2TlAsBr6\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$Rb_{2}TlAsBr_{6}$$\end{document} achieves a higher SLME of approximately 31.4 %, compared to Rb2CuAsBr6\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$Rb_{2}CuAsBr_{6}$$\end{document} which has a SLME of 7.44%. Moreover, the calculated thermoelectric properties show that Rb2TlAsBr6\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$Rb_{2}TlAsBr_{6}$$\end{document} exhibits enhanced thermoelectric performance compared to Rb2CuAsBr6\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$Rb_{2}CuAsBr_{6}$$\end{document}. These findings highlight the potential of lead-free perovskites, particularly Rb2TlAsBr6\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$Rb_{2}TlAsBr_{6}$$\end{document}, for next-generation solar cell applications. [ABSTRACT FROM AUTHOR]