燕山大学缑慧阳、美国乔治梅森大学Howard Sheng等研究人员合作合成出次晶态金刚石。相关论文于2021年11月24日发表在《自然》杂志上。
研究人员报告了一种不同于晶体或无定形金刚石的次晶体状态。这个次晶态金刚石，由亚纳米大小的次晶组成，拥有明确的晶体中程秩序，达到几个原子壳，是在高压高温条件下（例如，30GPa和1,600K）采用面心立方体C60作为前体合成的。通过X射线衍射、高分辨率透射显微镜和高级分子动力学模拟的结合，确定了次晶态的结构特征。次晶态的形成是压缩的C60中形成的密集分布的核点以及无定形金刚石中由于强sp3键而产生的明显的第二近邻短程有序性的结果。
次晶态金刚石的发现为富碳家族增加了一种不寻常的金刚石形式，它表现出与众不同的物理特性，可以被进一步利用来开发新材料。此外，这项工作揭示了非晶态和晶态之间长度尺度的缺失，对识别非晶态材料产生的复杂结构具有深远意义。
据悉，自然界中的固体一般可分为晶体和非晶体状态，取决于材料中是否存在长程晶格周期。然而，如果晶体中长程秩序的程度明显降低，这两种状态的区分可能面临根本性的挑战。
附：英文原文
Title: Synthesis of paracrystalline diamond
Author: Tang, Hu, Yuan, Xiaohong, Cheng, Yong, Fei, Hongzhan, Liu, Fuyang, Liang, Tao, Zeng, Zhidan, Ishii, Takayuki, Wang, Ming-Sheng, Katsura, Tomoo, Sheng, Howard, Gou, Huiyang
Issue&Volume: 2021-11-24
Abstract: Solids in nature can be generally classified into crystalline and non-crystalline states1,2,3,4,5,6,7, depending on whether long-range lattice periodicity is present in the material. The differentiation of the two states, however, could face fundamental challenges if the degree of long-range order in crystals is significantly reduced. Here we report a paracrystalline state of diamond that is distinct from either crystalline or amorphous diamond8,9,10. The paracrystalline diamond reported in this work, consisting of sub-nanometre-sized paracrystallites that possess a well-defined crystalline medium-range order up to a few atomic shells4,5,11,12,13, was synthesized in high-pressure high-temperature conditions (for example, 30GPa and 1,600K) employing face-centred cubic C60 as a precursor. The structural characteristics of the paracrystalline diamond were identified through a combination of X-ray diffraction, high-resolution transmission microscopy and advanced molecular dynamics simulation. The formation of paracrystalline diamond is a result of densely distributed nucleation sites developed in compressed C60 as well as pronounced second-nearest-neighbour short-range order in amorphous diamond due to strong sp3 bonding. The discovery of paracrystalline diamond adds an unusual diamond form to the enriched carbon family14,15,16, which exhibits distinguishing physical properties and can be furthered exploited to develop new materials. Furthermore, this work reveals the missing link in the length scale between amorphous and crystalline states across the structural landscape, having profound implications for recognizing complex structures arising from amorphous materials.
DOI: 10.1038/s41586-021-04122-w
