An international research team, led by scientists from The University of Texas at Austin, has unveiled a groundbreaking double moiré system made of four graphene layers. In this innovative structure, the top and bottom pairs form small-twist-angle bilayer graphene, while the middle interface is characterized by a large rotational mismatch. Fabricated using opto-thermoplasmonic nanolithography, this system introduces a new platform for exploring independently tunable flat bands in twisted bilayer graphene (TBG) structures.
This development represents a significant leap in the study of correlated electron systems and quantum materials. The double moiré system allows precise control of two sets of flat bands, one for each TBG subsystem, enabling independent tunability. Thermodynamic analysis reveals that correlated insulating states are most stable near the magic angle, while gapped states are more robust at larger twist angles. These findings deepen our understanding of electronic properties in 2D materials, offering exciting potential applications in quantum computing, sensors, and other advanced technologies.
The team’s findings, published in Physical Review Letters as an article entitled Independently tunable flat bands and correlations in a graphene double moiré system, highlight how this new system paves the way for transformative research in the field of quantum materials.
Key Collaborators
The study was led by Emanuel Tutuc, a professor in the Department of Electrical and Computer Engineering (ECE) and Texas Materials Institute at UT Austin, with contributions from:
Yimeng Wang and G. William Burg (ECE, Texas Materials Institute, UT Austin)
Jihang Zhu and Allan MacDonald (Department of Physics, Texas Materials Institute, UT Austin)
Anand Swain and Yuebing Zheng (Walker Department of Mechanical Engineering and Texas Materials Institute, UT Austin)
Kenji Watanabe and Takashi Taniguchi (National Institute of Materials Science, Japan)
The work at The University of Texas at Austin was supported by the National Science Foundation (NSF) grants MRSEC DMR-2308817, EECS-2122476, and PFI-2140985; Army Research Office under grant No. W911NF-22-1-2; the Welch Foundation grant F-2169-20230405; and Department of Energy grant DE-SC0019481.
