Graphene buffer layer on Si-terminated SiC : a multi-minima energy surface studied with an empirical interatomic potential

TL;DR

This study models the atomistic structure of the graphene buffer layer on Si-terminated SiC using a modified interatomic potential, revealing complex energy landscapes and resulting in a structure consistent with experimental and ab initio data.

Contribution

It introduces a specialized procedure to navigate the multi-minima energy surface for accurate structure prediction.

Findings

Hexagonal pattern with unsticked rods observed

Structure aligns with experimental patterns

Agreement with ab initio calculations

Abstract

The atomistic structure of the graphene buffer layer on Si-terminated SiC is studied using a modified environment-dependent interatomic potential (EDIP). The investigation of equilibrium state by conjuguate gradients suffers from a complex multi-minima energy surface. A dedicated procedure is therefore presented to provide a suitable initial configuration on the way to the minimum. The result forms an hexagonal pattern with unsticked rods to release the misfit with the surface. The structure presents an agreement with the global pattern obtained by experiments and even with the details of an ab initio calculation.