We identify by ab initio calculations a new cubic carbon phase in Pa3̄ (Th6) symmetry, which has a unit cell that comprises eight sp3-connected C 3 triangle rings (thus termed cubic C 3). The transformation from graphite occurs via a novel sheet-rumpling mechanism under anisotropic compression along the a axis, which is distinct from the usual c-axis compression mechanism for the graphite-to-diamond transition. Calculated structural parameters and simulated x-ray diffraction of cubic C 3 match the experimental data, thus resolving the long-standing problem of structural determination of a new carbon phase. The sheet-rumpling pathway unveiled here establishes a new mechanism for structural transformation in layered covalent materials.
|ジャーナル||Physical Review B - Condensed Matter and Materials Physics|
|出版ステータス||Published - 2012 6 5|
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