Synthesized hexagonal phases, Re 3 N and Re 2 N, have always been considered to be the ground-state structures of ruthenium-nitrides systems, whereas theoretical studies proposed cubic ( F -43m), tetragonal ( P 4 2 /mnm), orthorhombic ( P bca, P bcn), hexagonal ( P -6m2, P 6 3 /mmc), and monoclinc ( C 2/m) crystal phases as the stable ground state structure of Re-N systems. However, the present state-of-the-art evolutionary technique combined with first-principles theory calculations revealed that cubic P m-3m ReN is the real ground-state-phase of ReN systems under ambient conditions. The proposed cubic-ReN is found thermodynamically, mechanically and dynamically stable. The present study evinces that ReN has huge elastic constants C 11 (∼830 GPa), large bulk (∼415 GPa), and shear modulus (∼222 GPa). Theoretical Vickers hardness is estimated to be ∼20 GPa and thus support that ReN is ...

中文翻译：

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Re-N系统的极高不可压缩性和硬度

合成的六方相Re 3 N和Re 2 N一直被认为是氮化钌体系的基态结构，而理论研究则提出立方（F -43m），四方（P 4 2 / mnm）或正交晶（P bca，P bcn），六角形（P -6m2，P 6 3 / mmc）和单斜晶（C 2 / m）晶体相是Re-N系统的稳定基态结构。但是，目前的先进进化技术与第一性原理理论计算相结合，揭示了立方P m-3m ReN是环境条件下ReN系统的真实基态相。发现所提出的立方-ReN具有热力学，机械和动态稳定性。本研究表明，ReN具有巨大的弹性常数C 11（〜830 GPa），大体积（〜415 GPa）和剪切模量（〜222 GPa）。