Carbon rehybridization at the graphene/SiC(0001) interface: Effect on stability and atomic-scale corrugation

摘要

We address the energetic stability of the graphene/SiC(0001) interface andthe associated binding mechanism by studying a series of low-straincommensurate interface structures within a density functional scheme. Among thestructures with negligible strain, the 6\surd3\times6\surd3 R30{\deg} SiCperiodicity shows the lowest interface energy, providing a rationale for itsfrequent experimental observation. The interface stability is driven by theenhanced local reactivity of the substrate-bonded graphene atoms undergoingsp2-to-sp3 rehybridization (pyramidalization). By this mechanism, relaxedstructures of higher stability exhibit more pronounced graphene corrugations atthe atomic scale.