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Nonmonotonic Angle-Dependent Friction on Twisted Bilayer Graphene
Mengzhen Zhu1, Sen Wang2, Haoran Xu1
1Applied Mechanics Laboratory, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China.
Nano Letters
|March 10, 2026
Summary
Researchers explored friction in twisted bilayer graphene (TBG) superlattices. They found friction varies nonmonotonically with twist angle, revealing insights into controlling surface friction through moiré engineering.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Tribology
Background:
- Moiré superstructures in stacked 2D materials can tune tribological properties.
- Experimental data on friction's dependence on continuously varying moiré patterns is lacking.
Purpose of the Study:
- To systematically investigate the frictional response of twisted bilayer graphene (TBG) across a range of twist angles.
- To understand how moiré patterns influence friction and energy dissipation.
Main Methods:
- Systematic experimental investigation of frictional response.
- Measurement of lateral force modulation amplitude and frictional energy dissipation.
- Analysis of TBG samples with twist angles from 0.3° to 10.8°.
Main Results:
- Both lateral force amplitude and frictional energy dissipation showed nonmonotonic variations with twist angle.
- Lateral force amplitude peaked at ~3.0°, aligning with geometric predictions.
- Frictional energy dissipation reached its extremum at a smaller twist angle of ~1.2°.
Conclusions:
- The study reveals a distinct nonmonotonic trend in frictional behavior.
- This trend is driven by the interplay between local in-plane stiffness and atomic reconstruction.
- Results emphasize the importance of local stiffness in superstructures for controlling sliding dynamics and energy dissipation, informing moiré engineering for friction control.
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