Affiliation:
1. State Key Laboratory of Mechanics and Control for Aerospace Structures, Nanjing University of Aeronautics and Astronautics , No. 29 Yudao Street, Nanjing 210016, China
Abstract
Lateral compressions of (n, n) and (n, 0) single-walled carbon nanotube (SWCNT) bundles are simulated by density functional theory. Feasible transition pathways are verified by the body-centered tetragonal C4 (bct-C4) phase from the (4, 4) bundle and the carbon-centered orthorhombic C8 (Cco-C8) phase from (6, 6) and (8, 8) bundles. Three new phases, the sp3-hybridized phases Cco-C16 from the (4, 0) bundle and Cco-C32 from the (8, 0) bundle, the hexagonal phase Hex-C24 composed of sp2- and sp3-hybridized carbons from the (6, 0) bundle, under non-proportional triaxial loading are predicted. Measured hardness values for Cco-C16/C32 exceed 40 GPa, indicating super-hardness. Electronic band structures of Cco-C16/C32 exhibit a 3.64 eV bandgap, while Hex-C24 exhibits metallic carbon properties. Our results provide the potential phase transition pathways of SWCNT bundles under non-proportional compression.
Funder
National Natural Science Foundation of China
the Research Fund of State Key Laboratory of Mechanics and Control for Aerospace Structure
Project Funded by Priority Academic Program Development of Jiangsu higher Education Institutions
Natural Science Foundation of Jiangsu Province
Subject
General Physics and Astronomy