(Invited) Pressure-Induced New Carbon Materials with New Properties

Abstract

Design and synthesis of new carbon materials have been attracting intensive attention due to their application in various fields. The study of carbon nanostructures under high pressure provides us a very effective method to create new carbon material which is hardly discovered at ambient conditions because of the appearance of nanometer scale size effect and the novel high pressure behavior. In this presentation, several examples on high pressure induced novel structures in recently studied fullerene based molecular cocrystals will be outlined. Particularly, anomalous negative volume compressibility observed in the eutectic Sc3N@C80 -cubane crystal under high pressure will be introduced. The charge transfer from fullerene cage to cubane promotes the configuration change of cubane, which transforms into a “low density” configuration, resulting in an abnormal lattice expansion of the crystal. This is the first experimentally discovered crystal which has negative volume compressibility. We will also present the synthesis of nearly all sp3 amorphous carbon bulk material from high temperature and high pressure (HPHT)-treated C60 for the first time. This new sp3 amorphous carbon material shows an optical band gap of ~2.7eV and extremely high Vickers hardness of 102 GPa under 9.8N load, close to that of diamond, which is a multifunctional superhard amorphous carbon material with the highest thermal conductivity and hardness known in the amorphous materials up to now.