摘要
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-Si C(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 ~70 V in a typical gated BLG/SiO_(2)/Si device. The finding in interfacemodulated 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.
作者
刘超飞
王健
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)
基金
supported by the National Natural Science Foundation of China (Grant Nos. 11888101 and 11774008)
the National Key R&D Program of China (Grant Nos. 2018YFA0305604 and 2017YFA0303302)
the Beijing Natural Science Foundation (Grant No. Z180010)
the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDB28000000)。