High pressure diamond-like liquid carbon

TL;DR

This paper uses molecular dynamics simulations to show that liquid carbon undergoes a gradual transition to a diamond-like structure under high pressure, emphasizing the importance of long-range interactions in modeling carbon.

Contribution

It demonstrates that incorporating long-range interactions in empirical potentials is essential to accurately reproduce the diamond-like liquid phase of carbon.

Findings

Liquid carbon transitions to a diamond-like structure under high pressure.

Short-range potentials fail to reproduce the diamond structure.

Long-range interactions are crucial for modeling carbon phases.

Abstract

We report density-functional based molecular dynamics simulations, that show that, with increasing pressure, liquid carbon undergoes a gradual transformation from a liquid with local three-fold coordination to a 'diamond-like' liquid. We demonstrate that this unusual structural change is well reproduced by an empirical bond order potential with isotropic long range interactions, supplemented by torsional terms. In contrast, state-of-the-art short-range bond-order potentials do not reproduce this diamond structure. This suggests that a correct description of long-range interactions is crucial for a unified description of the solid and liquid phases of carbon.