Large scale simulation of quantum-mechanical molecular dynamics for nano-polycrystalline diamond

TL;DR

This study uses large-scale quantum-mechanical molecular dynamics simulations to investigate potential precursor states of nano-polycrystalline diamond, revealing metastable domains that could lead to its formation from graphite.

Contribution

It introduces a large-scale 'order-N' simulation approach to explore the atomic-scale precursor structures of nano-polycrystalline diamond from graphite.

Findings

Identification of graphite-like and diamond-like domains as potential precursors

Simulation of structures with 10^5 atoms demonstrating metastable states

Insight into the atomic-scale processes leading to nano-polycrystalline diamond formation

Abstract

Quantum-mechanical molecular-dynamics simulations are carried out to explore possible precursor states of nano-polycrystalline diamond, a novel ultra-hard material produced directly from graphite. Large-scale simulation with 10^5 atoms is realized by using the ' order-N' simulation code 'ELSES' (http://www.elses.jp). The simulation starts with a diamond structure that contains initial structural defects and results in a mixture of graphite(sp^2)-like and diamond(sp^3)-like regions as nano-meter-scale domains. We speculate that the domains are metastable and are possible candidates of the precursor structures.