Low-temperature phase transformation from nanotube to sp3 superhard carbon phase*
Xu Ninga)†, Li Jian-Fub), Huang Bo-Longb), Wang Bao-Lina)‡
       
Two new phases (constructed from the (9, 0), and (4, 0) CNTs under pressures above 45 GPa and 255 GPa, respectively) under different decompression conditions. The (9, 0) carbon has an antisymmetric structrue compared with the symmetric bct -C4 structrue [Ref. [ 23 ]].