新型超硬材料I-4碳的第一性原理研究

应用基于粒子群优化算法的卡里普索(CALYPSO)晶体结构预测方法 ,发现了一种新型的具有四方结构的C的同素异形体,空间群为I-4,将其命名为I-4碳.利用基于密度泛函理论的第一性原理计算方法对I-4碳的电子能带结构、电子态密度、声子谱、弹性常数以及体弹模量进行研究.计算结果发现:I-4碳动力学稳定,并且具有较大的体弹模量(432.12 GPa)和剪切模量(488.46 GPa);同时,从理论上算出其维氏硬度值可达到83.35 GPa.计算结果表明:I-4碳有望成为一种潜在的超硬材料.

First-principles of Novel Superhard I-4 Carbon Allotrope

Using CALYPSO crystal structure prediction method via particle swarm optimization,a novel sp3 carbon allotrope possessing a tetragonal lattice with the space group I-4 was found, namely I-4 carbon. The band structure,electronic density of states,phonon dispersion,elastic constants,and bulk modulus of I-4 carbon were performed by using first-principles calculations based on density functional theory. The results reveal that I-4 carbon is dynamically stable,and simultaneously posses a high bulk modulus of 432. 12 GPa and a high shear modulus of 488. 46 GPa. Furthermore,we have theoretically calculated that the Vickers hardness value of I-4 carbon is 83. 35 GPa. The theoretical results indicate that I-4 carbon may be a potential superhard material.