Strain-modulated Intercalated Phases of Pb Monolayer with Dual Periodicity in SiC(0001)-Graphene Interface
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| Format: | Preprint |
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2024
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| _version_ | 1866912149001994240 |
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| author | Wang, Lin-Lin Chen, Shen Kolmer, Marek Han, Yong Tringides, Michael C. |
| author_facet | Wang, Lin-Lin Chen, Shen Kolmer, Marek Han, Yong Tringides, Michael C. |
| contents | Intercalation of metal atoms at the SiC(0001)-graphene (Gr) interface can provide confined 2D metal layers with interesting properties. The intercalated Pb monolayer (ML) has shown the coexistence of the Gr(10x10)-moire and a stripe phase, which still lacks understanding. Using density functional theory calculation and thermal annealing with ab initio molecular dynamics, we have studied the formation energy of SiC(0001)/Pb/Gr for different coverages of intercalated Pb. Near the coverage of a Pb(111)-like ML mimicking the (10x10)-moire, we find a slightly more stable stripe structure, where one half of the structure has compressive strain with Pb occupying the Si-top sites and the other half has tensile strain with Pb off the Si-top sites. This stripe structure along the Gr zigzag direction has a periodicity of 2.3 nm across the [1-210] direction agreeing with the previous observations using scanning tunneling microscopy. Analysis with electron density difference and density of states show the tensile region has a more metallic character than the compressive region, while both are dominated by the charge transfer from the Pb ML to SiC(0001). The small energy difference between the stripe and Pb(111)-like structures means the two phases are almost degenerate and can coexist, which explains the experimental observations. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2408_02886 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Strain-modulated Intercalated Phases of Pb Monolayer with Dual Periodicity in SiC(0001)-Graphene Interface Wang, Lin-Lin Chen, Shen Kolmer, Marek Han, Yong Tringides, Michael C. Materials Science Mesoscale and Nanoscale Physics Intercalation of metal atoms at the SiC(0001)-graphene (Gr) interface can provide confined 2D metal layers with interesting properties. The intercalated Pb monolayer (ML) has shown the coexistence of the Gr(10x10)-moire and a stripe phase, which still lacks understanding. Using density functional theory calculation and thermal annealing with ab initio molecular dynamics, we have studied the formation energy of SiC(0001)/Pb/Gr for different coverages of intercalated Pb. Near the coverage of a Pb(111)-like ML mimicking the (10x10)-moire, we find a slightly more stable stripe structure, where one half of the structure has compressive strain with Pb occupying the Si-top sites and the other half has tensile strain with Pb off the Si-top sites. This stripe structure along the Gr zigzag direction has a periodicity of 2.3 nm across the [1-210] direction agreeing with the previous observations using scanning tunneling microscopy. Analysis with electron density difference and density of states show the tensile region has a more metallic character than the compressive region, while both are dominated by the charge transfer from the Pb ML to SiC(0001). The small energy difference between the stripe and Pb(111)-like structures means the two phases are almost degenerate and can coexist, which explains the experimental observations. |
| title | Strain-modulated Intercalated Phases of Pb Monolayer with Dual Periodicity in SiC(0001)-Graphene Interface |
| topic | Materials Science Mesoscale and Nanoscale Physics |
| url | https://arxiv.org/abs/2408.02886 |