Superlattice potentials are theoretically predicted to modify the single-particle electronic structures.The resulting Coulomb-interaction-dominated low-energy physics would generate highly novel many-body phenomena.Here,by in situ tunneling spectroscopy,we show the signatures of superstructure-modulated correlated electron states in epitaxial bilayer graphene(BLG)on 6H-SiC(0001).As the carrier density is locally quasi-'tuned'by the superlattice potentials of a 6×6 interface reconstruction phase,the spectral-weight transfer occurs between the two broad peaks flanking the charge-neutral point.Such a detected non-rigid band shift beyond the single-particle band description implies the existence of correlation effects,probably attributed to the modified interlayer coupling in epitaxial BLG by the 6×6 reconstruction as in magic-angle BLG by the moiré potentials.Quantitative analysis suggests that the intrinsic interface reconstruction shows a high carrier tunability of～1/2 filling range,equivalent to the back gating by a voltage of～70V in a typical gated BLG/SiO2/Si device.The finding in interface-modulated epitaxial BLG with reconstruction phase extends the BLG platform with electron correlations beyond the magic-angle situation,and may stimulate further investigations on correlated states in graphene systems and other van der Waals materials.

Chaofei Liu;Jian Wang

International Center for Quantum Materials,School of Physics,Peking University,Beijing 100871,China;CAS Center for Excellence in Topological Quantum Computation,University of Chinese Academy of Sciences,Beijing 100190,China;Beijing Academy of Quantum Information Sciences,Beijing 100193,China

中国物理快报（英文版）

[1]Chaofei Liu;Jian Wang-.Spectroscopic Evidence for Electron Correlations in Epitaxial Bilayer Graphene with Interface-Reconstructed Superlattice Potentials)[J].中国物理快报（英文版）,2022(07):91-100

Superlattice,70V

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