Strain-modulated Intercalated Phases of Pb Monolayer with Dual Periodicity in SiC(0001)-Graphene Interface

• DOI: 10.48550/arxiv.2408.02886
• Publication Date: 2024-08-05
• Authors: Linlin Wang; Shen Chen; Marek Kolmer; Han Yong; Michael C. Tringides
• Keywords: Interface (matter); Strain (injury)

Intercalation of metal atoms at the SiC(0001)-graphene (Gr) interface can provide confined 2D layers with interesting properties. The intercalated Pb monolayer (ML) has shown coexistence Gr(10x10)-moire and a stripe phase, which still lacks understanding. Using density functional theory calculation thermal annealing ab initio molecular dynamics, we have studied formation energy SiC(0001)/Pb/Gr for different coverages Pb. Near coverage Pb(111)-like ML mimicking (10x10)-moire, find slightly more stable structure, where one half structure compressive strain occupying Si-top sites other tensile off sites. This along Gr zigzag direction periodicity 2.3 nm across [1-210] agreeing previous observations using scanning tunneling microscopy. Analysis electron difference states show region metallic character than region, while both are dominated by charge transfer from to SiC(0001). small between structures means two phases almost degenerate coexist, explains experimental observations.