Urtra-Hard Bonds in P-Carbon Stronger than Diamond

【摘要】：The hardness and ideal strength of P-carbon,i.e.,a new carbon phase for the cold-compressed carbon with an orthogonal structure recently proposed and named as P-carbon,are investigated by means of first-principles calculations.The strength calculations reveal that the failure mode in P-carbon is dominated by the tensile type.The ideal tensile strength of P-carbon is calculated to be 76.7 GPa in the [001]direction,which is higher than that of the previously known most stable Z-carbon,of 71.4 GPa.Meanwhile,the theoretical Vickers hardness of P-carbon is estimated as 89 GPa,which is comparable with that of diamond.Especially,two types of bonds in P-carbon with hardness values of 114 GPa and 105 GPa are significantly stronger than those of diamond.The results provide insight into exploration of the ultra-hard P-carbon for potentially technological applications.