Zhang Yu-Tian, Wang Yun-Peng, Zhang Xianli, Zhang Yu-Yang, Du Shixuan, Pantelides Sokrates T
University of Chinese Academy of Sciences and Institute of Physics, Chinese Academy of Sciences, Beijing 100049, China.
Hunan Key Laboratory for Super Microstructure and Ultrafast Process, School of Physics and Electronics, Central South University, Changsha 410083, China.
Nano Lett. 2022 Oct 12;22(19):8018-8024. doi: 10.1021/acs.nanolett.2c02542. Epub 2022 Aug 12.
The structure of amorphous materials has been debated since the 1930s as a binary question: amorphous materials are either Zachariasen continuous random networks (Z-CRNs) or Z-CRNs containing crystallites. It was recently demonstrated, however, that amorphous diamond can be synthesized in either form. Here we address the question of the structure of single-atom-thick amorphous monolayers. We reanalyze the results of prior simulations for amorphous graphene and report kinetic Monte Carlo simulations based on alternative algorithms. We find that crystallite-containing Z-CRN is the favored structure of elemental amorphous graphene, as recently fabricated, whereas the most likely structure of binary monolayer amorphous BN is altogether different than either of the two long-debated options: it is a compositionally disordered "pseudo-CRN" comprising a mix of B-N and noncanonical B-B and N-N bonds and containing "pseudocrystallites", namely, honeycomb regions made of noncanonical hexagons. Implications for other nonelemental 2D and bulk amorphous materials are discussed.
自20世纪30年代以来，非晶态材料的结构一直作为一个二元问题存在争议：非晶态材料要么是扎卡里亚森连续随机网络（Z-CRNs），要么是包含微晶的Z-CRNs。然而，最近有研究表明，非晶态金刚石可以以这两种形式合成。在此，我们探讨单原子厚非晶态单层的结构问题。我们重新分析了先前关于非晶态石墨烯模拟的结果，并报告了基于替代算法的动力学蒙特卡罗模拟。我们发现，如最近制备的那样，含微晶的Z-CRN是元素非晶态石墨烯的有利结构，而二元单层非晶态BN最可能的结构与长期以来争论的两种结构完全不同：它是一种成分无序的“伪CRN”，由B-N键、非标准B-B键和N-N键混合而成，并包含“伪微晶”，即由非标准六边形构成的蜂窝状区域。文中还讨论了对其他非元素二维和块状非晶态材料的影响。
