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Topological and Stacked Flat Bands in Bilayer Graphene with a Superlattice Potential
- Source :
- Physical Review Letters. 130
- Publication Year :
- 2023
- Publisher :
- American Physical Society (APS), 2023.
-
Abstract
- We show that bilayer graphene in the presence of a 2D superlattice potential provides a highly tunable setup that can realize a variety of flat band phenomena. We focus on two regimes: (i) topological flat bands with non-zero Chern numbers, C, including bands with higher Chern numbers |C| > 1; and (ii) an unprecedented phase consisting of a stack of nearly perfect flat bands with C = 0. For realistic values of the potential and superlattice periodicity, this stack can span nearly 100 meV, encompassing nearly all of the low-energy spectrum. We further show that in the topological regime, the topological flat band has a favorable band geometry for realizing a fractional Chern insulator (FCI) and use exact diagonalization to show that the FCI is in fact the ground state at 1/3 filling. Our results provide a realistic guide for future experiments to realize a new platform for flat band phenomena.<br />Comment: 14 pages including supplementary materials. Published version
Details
- ISSN :
- 10797114 and 00319007
- Volume :
- 130
- Database :
- OpenAIRE
- Journal :
- Physical Review Letters
- Accession number :
- edsair.doi.dedup.....7296117d0e210b08ac956465aae3ddcd