2025/10/22 by Souvik Sasmal, Ryan Muzzio, Sasmal, Souvik +27
Engineering · Materials Science · Physics and Astronomy · #2D Materials and Applications #Graphene research and applications #Plasmonic and Surface Plasmon Research #cond-mat.mes-hall #cond-mat.str-el
paper · pdf · doi:10.48550/arxiv.2510.19632
openalex publication_date 2025/10/22 · openalex created_date 2025/10/24 · openalex updated_date 2026/07/30
The symmetry-broken correlated states in twisted double bilayer graphene (TDBG) can be tuned via several external knobs, including twist angle, displacement field, and carrier density. However, a direct, momentum-resolved characterization of how these parameters reshape the flat-band structure remains limited. In this Letter, we employ microfocused angle-resolved photoemission spectroscopy to investigate the flat-band dispersion of TDBG at a twist angle of 1.6°, systematically varying the displacement field and carrier density via electrostatic gating. We directly observe multiple flat moiré minibands near charge neutrality, including a flat remote valence band residing below the low-energy flat-band manifold. Furthermore, the dominant Coulomb repulsive energy over the flat-band bandwidth suggests favorable conditions for the emergence of interaction-driven correlated phenomena in TDBG. These findings establish that the formation and evolution of flat bands in TDBG arises from the interplay between the electron filling and the displacement field.