Theoretical prediction of electronic, mechanical, and thermodynamic properties of layered ternary compounds (UC)nM3C2 (M=Si or Al; n=1,2) and two-dimensional U2C

Abstract

Following the 2011 Fukushima Daiichi nuclear catastrophe, there has been a significant surge in interest towards innovative materials capable of enhancing the safety, performance, and efficiency of nuclear reactors. This study introduces a new class of layered ternary compounds, specifically (UC)_nSi₃C₂ (n = 1,2), and derived two-dimensional (2D) U₂C, discovered through first-principles calculations. We predict the electronic, mechanical, and thermodynamic properties of these compounds within the PBE and PBE + U frameworks, with a comparative analysis of the (UC)_nAl₃C₂ (n = 1,2) series. Our findings reveal that the USi₃C₃ and U₂Si₃C₄ compounds exhibit mechanical and dynamic stabilities, suggesting their potential for experimental synthesis under specific conditions. These compounds demonstrate superior mechanical and thermal properties as nuclear fuels, including higher elastic moduli and improved ductility compared to (UC)_nAl₃C₂ compounds. The mechanical and dynamical stabilities of 2D U₂C are confirmed, and the calculated thermal conductivity and mechanical properties position it as a promising candidate for high-performance nuclear fuel applications. We anticipate that the present work will bolster future experimental endeavors and help explore the practical applications of these novel materials in future nuclear systems.