Orthorhombic C32: a novel superhard sp3 carbon allotrope

• Published in: Physical chemistry chemical physics : PCCP 2013-09, Vol.15 (33), p.1412-14125
• Main Authors: Zhang, Miao, Liu, Hanyu, Du, Yonghui, Zhang, Xinxin, Wang, Yanchao, Li, Quan
• Format: Article
• Language: English
• Subjects: Chemistry; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; General and physical chemistry; Physics; Structure of solids and liquids; crystallography
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/c3cp51746b

Using a recently developed 'Crystal structure AnaLYsis by Particle Swarm Optimization' (CALYPSO) algorithm on a structural search, we predicted a novel sp 3 carbon allotrope possessing an orthorhombic lattice with the space group Cmmm ( o C32). The calculated elastic constants and the simulated hardness revealed that o C32 simultaneously possesses ultra-incompressible and superhard properties with a high bulk modulus of 457 GPa and a high Vickers hardness of 96.2 GPa. This o C32 phase is dynamically stable and energetically more preferable than the experientially observed cold-compressed carbon, thus o C32 is expected to be experimentally synthesizable under extreme conditions. These results further expand the list of meta-stable carbon allotropes and superhard materials under atmospheric and extreme conditions. Using a recently developed 'Crystal structure AnaLYsis by Particle Swarm Optimization' (CALYPSO) algorithm on a structural search, we predicted a novel sp 3 carbon allotrope possessing an orthorhombic lattice with the space group Cmmm ( o C32).