An Energy Landscape for Elemental Carbon

Abstract

The potential energy surface of an 8-atom periodic cell of carbon is explored using discrete path sampling with the energy, forces, and stress tensor represented by the MACE-MATPES-r2SCAN-0 potential evaluated via an interface to the Atomic Simulation Environment. The resulting enthalpy landscape is explored as a function of pressure and compared to the experimental phase diagram. Several interesting pathways between different phases are analyzed in detail, including symmetry analysis for degenerate rearrangements of periodic crystals. We also considered the effect of a dispersion correction on the energetics and structure of selected crystals. The approach employed here is generally applicable for materials and condensed phase modeling.