Liao Mingqing, Wang Yi, Wang Fengjiang, Zhu Jingchuan, Liu Zi-Kui
School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, China.
Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, 16802, USA.
Phys Chem Chem Phys. 2022 Oct 5;24(38):23561-23569. doi: 10.1039/d2cp03031d.
A new carbon allotrope, pentadiamond, was recently reported in the literature. Herein, we investigate its thermal expansion and thermoelastic properties by first principles. It is observed that the bulk modulus and hardness of pentadiamond are far less than those of diamond, but the thermal expansion of pentadiamond is lower than that of diamond in the range of 0 K to 2000 K, and even negative in the temperature range of 0-190 K. The negative thermal expansion at low temperature originates from the transverse vibrations of the edge-shared atoms in the coplanar double-pentagon. The low thermal expansion at high temperature is contributed by the strong bonds in pentadiamond. Benefiting from the low thermal expansion, the elastic constants of pentadiamond decrease very slowly with respect to temperature compared with those of diamond. The low sensitivity of thermodynamic and thermoelastic properties to temperature makes pentadiamond a promising material for high anti-thermal-shock and accurate electronic device applications.
一种新的碳同素异形体——五角金刚石，最近在文献中被报道。在此，我们通过第一性原理研究其热膨胀和热弹性性质。据观察，五角金刚石的体模量和硬度远低于金刚石，但在0 K至2000 K范围内，五角金刚石的热膨胀低于金刚石，甚至在0 - 190 K温度范围内为负。低温下的负热膨胀源于共面双五角形中边缘共享原子的横向振动。高温下的低热膨胀是由五角金刚石中的强键所致。受益于低热膨胀，与金刚石相比，五角金刚石的弹性常数随温度下降非常缓慢。热力学和热弹性性质对温度的低敏感性使五角金刚石成为用于高抗热震和精确电子器件应用的有前途的材料。
