2013/10/19 by Huijuan Cui, Xian‐Lei Sheng, Cui, Hui-Juan +7
Earth and Planetary Sciences · Materials Science · #Boron and Carbon Nanomaterials Research #Diamond and Carbon-based Materials Research #FOS: Physical sciences #High-pressure geophysics and materials #Materials Science (cond-mat.mtrl-sci)
paper · pdf · doi:10.48550/arxiv.1310.5228
openalex publication_date 2013/10/19 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Superstructures of cubic and hexagonal diamonds (h- and c-diamond) comprising a family of stable diamond-like sp3 hybridized novel carbon allotropes are proposed, which are referred to as Un-carbon where n ≥ 2 denotes the number of structural layers in a unit cell. The conventional h- and c-diamond are included in this family as members with n=2 and 3, respectively. Un-carbon (n=4-6), which are unveiled energetically and thermodynamically more stable than h-diamond and possess remarkable kinetic stabilities, are shown to be insulators with indirect gaps of 5.6 ∼ 5.8 eV, densities of 3.5 ∼ 3.6 g/cm3, bulk modulus of 4.3 ∼ 4.4 × 102 GPa, and Vickers hardness of 92.9 ∼ 97.5 GPa even harder than h- and c-diamond. The simulated x-ray diffraction and Raman spectra are presented for experimental characterization. These new structures of carbon would have a compelling impact in physics, chemistry, materials science and geophysics.