Structural Evolution of C60 Molecular Crystal Predicted by Neural Network Potential

Abstract

AbstractThe preparation of fullerene and a wide range of derivatives has attracted much attention in past decades. Understanding the structural evolution starting from fullerene is critical to guide the experimental exploration but has been paid less attention yet. Using ab initio molecular dynamics or global structural search algorithm accompanied with density functional theory calculations can give a glance of the potential energy surface (PES), but suffers high cost and low efficiency. Herein, by using neural network potentials and stochastic surface walking global structural search method, an accelerated energy calculation, and the higher efficient PES mapping starting from C60 molecular crystal are reported. The structural evolution is found to follow an order of molecular crystal → polymers → opened caged ordered structures → 3D) curved carbon and graphite under zero pressure. Under high pressures, e.g., 50 GPa, the evolution follows a pathway of fullerene → sp2 and sp3 hybrid carbon → sp3 amorphous carbon and crystal diamond. The electronic property calculation of the obtained structures in the evolution pathway shows a band gap depending on the order parameter of the generated structures, suggesting that more novel carbons can be potentially prepared in experiments, starting from C60.