Regensburg 2025 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 88: 2D Materials: Stacking and Heterostructures (joint session O/HL)
O 88.2: Vortrag
Donnerstag, 20. März 2025, 15:15–15:30, H6
Gate-Tunable miniband dispersion in twisted graphene superlattices near the magic angle measured with MicroARPES — •Alfred J. H. Jones1, Zhihao Jiang1, Dongkyu Lee2, Youngji Park2, Kimberly Hsieh1, Paulina Majchrzak1, Chakradhar Sahoo1, Thomas S. Nielsen1, Kenji Watanabe3, Takashi Taniguchi3, Philip Hofmann1, Jill A. Miwa1, Yong P. Chen1,4, Jeil Jung2, and Søren Ulstrup1 — 1Department of Physics and Astronomy, Aarhus University, Denmark — 2Department of Physics, University of Seoul, Korea — 3National Institute for Materials Science, Japan — 4Department of Physics and Astronomy, Purdue University, USA
Twisted superlattices of mono- and bilayer-graphene are emerging as powerful tools to explore quantum many-body effects such as unconventional superconductivity and Mott insulating states. Access to the momentum-resolved electronic structure simultaneous to changing the carrier concentration and displacement field within a twisted superlattice device can directly provide key information on the miniband dispersion tunability that underpins the correlated phenomena.
Here, we present microARPES measurements from SGM4 at ASTRID2 on two-terminal "near-magic-angle" twisted bilayer (TBG) and double-bilayer graphene (TDBG) devices. Our findings for the two systems are strikingly different: On TBG, we find a filling factor-dependent bandwidth change of the flat moiré bands, whereas on TDBG the effect of tuning the doping and displacement field leads to non-monotonous bandwidth changes and tunable gap opening effects.
Keywords: Magic Angle Graphene; Graphene; Minibands; MicroARPES