Jiang Xue, Århammar Cecilia, Liu Peng, Zhao Jijun, Ahuja Rajeev
Department of Materials and Engineering, Royal Institute of Technology, 10044 Stockholm, Sweden.
Sci Rep. 2013;3:1877. doi: 10.1038/srep01877.
Pressure-induced bond type switching and phase transformation in glassy carbon (GC) has been simulated by means of Density Functional Theory (DFT) calculations and the Stochastic Quenching method (SQ) in a wide range of pressures (0-79 GPa). Under pressure, the GC experiences a hardening transition from sp- and sp(2)-type to sp(3)-type bonding, in agreement with previous experimental results. Moreover, a new crystalline carbon allotrope possessing R3 symmetry (R3-carbon) is predicted using the stochastic SQ method. The results indicate that R3-carbon can be regarded as an allotrope similar to that of amorphous GC. A very small difference in the heat of formation and the coherence of the radial and angular distribution functions of GC and the R3-carbon structure imply that small perturbations to this crystalline carbon allotrope may provide another possible amorphization pathway of carbon besides that of quenching the liquid melt or gas by ultra-fast cooling.
通过密度泛函理论（DFT）计算和随机淬火方法（SQ），在广泛的压力范围（0 - 79 GPa）内模拟了玻璃态碳（GC）中压力诱导的键型转变和相变。在压力作用下，GC经历了从sp型和sp(2)型键合到sp(3)型键合的硬化转变，这与先前的实验结果一致。此外，使用随机SQ方法预测了一种具有R3对称性的新型结晶碳同素异形体（R3 - 碳）。结果表明，R3 - 碳可被视为类似于非晶态GC的一种同素异形体。GC与R3 - 碳结构的生成热以及径向和角向分布函数的相干性差异非常小，这意味着对这种结晶碳同素异形体的微小扰动可能为碳提供除通过超快冷却淬冷液态熔体或气体之外的另一种可能的非晶化途径。
