基于第一性原理的近似金刚石的新型超硬四方相八碳C8
材料科学
2022-09-13 v2
摘要
提出了一种具有类似金刚石力学、动力学和热学性质的新型超硬碳同素异形体。基于密度泛函理论(DFT)计算得到的能量判据，确定了四方相C8化学计量比为角共享C4四面体的内聚网络，电荷密度投影显示其具有类sp3的碳杂化。该新同素异形体在力学(弹性常数)和动力学(声子)上稳定，其热学性质(热容CV)与文献中金刚石的实验数据高度吻合。根据所用模型对维氏硬度的评估，推测该新同素异形体的硬度大于金刚石。电子能带结构计算显示其具有像金刚石一样带隙为5 eV的大带隙绝缘行为。
引用
@article{arxiv.2206.05918,
title = {Novel Ultra-hard tetragonal Octacarbon C8 close to Diamond from First Principles},
author = {Samir F. Matar},
journal= {arXiv preprint arXiv:2206.05918},
year = {2022}
}
备注
A careful analysis with symmetry finder "PLATON" software -that was not available at the time of publication- and exchanges with colleagues who drew my attention to the issue, reveal that the C8 allotrope is nothing else than diamond expressed in another space group but whose primitive cell is that of diamond. So there's no point in presenting well known results of tetragonal octacarbon C8