High‐Pressure Synthesis of oP 28‐C 3 N 4 Recoverable to Ambient Conditions

作者：Dominique Laniel, Florian Trybel, Wenju Zhou, Andrey Aslandukov, James Spender, Ferenc Tasnádi, Timofey Fedotenko, Umbertoluca Ranieri, Akun Liang, Alena Aslandukovа, Fariia Iasmin Akbar, Yuqing Yin, Stella Chariton, Anna Pakhomova, Gastón Garbarino, Mohamed Mézouar, Michael Hanfland, Vitali B. Prakapenka, Igor A. Abrikosov, Leonid Dubrovinsky, Natalia Dubrovinskaia · 发表于：Advanced Functional Materials · 年份：2024 · DOI：10.1002/adfm.202416892 · 被引用次数：10 · 研究领域：Luminescence Properties of Advanced Materials、Machine Learning in Materials Science、Electronic and Structural Properties of Oxides

Abstract The thermodynamic parameter pressure is ideal for producing novel ultraincompressible and superhard materials as it promotes the formation of polymeric frameworks and higher atomic coordination. In this regard, carbon and nitrogen are particularly attractive elements as they can produce extended arrangements of strong covalent bonds. In this study, a previously unobserved C 3 N 4 polymorph, denoted as oP 28‐C 3 N 4 ( Pnnm , #58), is synthesized at pressures between 73 and 104 GPa in laser‐heated diamond anvil cells and found recoverable to ambient conditions and stable in air. The crystal structure of oP 28‐C 3 N 4 , comprised of corner‐sharing CN 4 tetrahedra, is solved and refined using synchrotron single‐crystal X‐ray diffraction. With a bulk modulus of 334(3) GPa deduced from experimental data, the compound is highly incompressible. Based on macroscopic and microscopic calculations, its hardness may achieve 47.5 or 79.7 GPa, respectively, making it a superhard material. Incompressibility of CN 4 tetrahedra in all experimentally observed C 3 N 4 polymorphs is found to be greater than that of the CC 4 and BN 4 tetrahedra forming the structures of diamond and cubic boron nitride. Density functional theory calculations provide further insight into the electronic, vibrational, and mechanical properties of oP 28‐C 3 N 4 , as well as their stability relative to other C─N phases.