旧事新说：石墨到金刚石转变的再审视
Old Story New Tell: The Graphite to Diamond Transition Revisited
AI总结：
本文通过大规模分子动力学模拟揭示石墨到金刚石转变中晶核起源于晶界并沿[001]和[120]双方向择优生长，立方金刚石为动力学有利产物，六方金刚石以孪晶形式少量出现，并结合HR-TEM实验验证了共格界面关系，调和了长期争论并为微观结构工程提供原子尺度指导。
摘要：
石墨和金刚石是两种众所周知的碳同素异形体，由于原子连接方式不同而具有截然不同的物理性质。石墨具有层状结构，其中的蜂窝状碳片层可以轻易滑移，而金刚石中的原子在三个维度上都以强键结合。从石墨到金刚石的转变一直是物理科学中的一个核心课题。将石墨转变为金刚石的一种方法是施加高压高温（HPHT）条件。然而，这一转变的原子尺度机制仍存在争议。通过一系列大规模分子动力学（MD）模拟，我们报告了一种机制：金刚石晶核起源于石墨晶界，并沿两个择优方向扩展。除了被广泛接受的[001]方向之外，我们发现沿石墨[120]方向的生长甚至更快。在这一情形下，立方金刚石（CD）是动力学上有利的产物，而六方金刚石（HD）则会以少量孪晶结构的形式出现在两个主要方向上。遵循晶体学取向关系，共格界面t-(100)gr//(11-1)cd + [010]gr//[1-10]cd也通过高分辨率透射电子显微镜（HR-TEM）实验得到了证实。所提出的相变机制不仅调和了关于HD在石墨-金刚石转变中作用的长期争论，而且为通过受控固相转变进行微观结构工程提供了原子尺度的见解。
英文摘要：
Graphite and diamond are two well-known allotropes of carbon with distinct physical properties due to different atomic connectivity. Graphite has a layered structure in which the honeycomb carbon sheets can easily glide, while atoms in diamond are strongly bonded in all three dimensions. The transition from graphite to diamond has been a central subject in physical science. One way to turn graphite into diamond is to apply the high pressure and high temperature (HPHT) conditions. However, atomistic mechanism of this transition is still under debate. From a series of large-scale molecular dynamics (MD) simulations, we report a mechanism that the diamond nuclei originate at the graphite grain boundaries and propagate in two preferred directions. In addition to the widely accepted [001] direction, we found that the growth along [120] direction of graphite is even faster. In this scenario, cubic diamond (CD) is the kinetically favorable product, while hexagonal diamond (HD) would appear as minor amounts of twinning structures in two main directions. Following the crystallographic orientation relationship, the coherent interface t-(100)gr//(11-1)cd + [010]gr//[1-10]cd was also confirmed by high-resolution transmission electron microscopy (HR-TEM) experiment. The proposed phase transition mechanism does not only reconcile the longstanding debate regarding the role of HD in graphite-diamond transition, but also yields the atomistic insight into microstructure engineering via controlled solid phase transition.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
