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Breakdown of the interlayer coherence in twisted bilayer graphene
Youngwook Kim1, Hoyeol Yun, Seung-Geol Nam
1Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea.
Physical Review Letters
|March 19, 2013
Summary
Twisted bilayer graphene completely suppresses coherent electron conduction between layers, even at atomic separations. This incoherent transport, unlike in graphite, shows strong temperature and electric field dependence.
Area of Science:
- Solid-state physics
- Materials science
- Condensed matter physics
Background:
- Coherent electron motion in Bloch states is fundamental to charge conduction in solids.
- Interlayer conduction in layered materials often fails due to reduced interlayer coupling, especially with large separations.
Purpose of the Study:
- To investigate charge conduction in twisted bilayer graphene.
- To determine if coherent conduction is suppressed in twisted bilayer graphene at the atomic scale.
Main Methods:
- Experimental measurement of interlayer resistivity in twisted bilayer graphene.
- Comparison of resistivity with Bernal-stacked graphite.
- Analysis of temperature and external electric field dependence of resistivity.
Main Results:
- Complete suppression of coherent conduction observed in twisted bilayer graphene.
- Interlayer resistivity is significantly higher than in Bernal-stacked graphite.
- Resistivity shows strong dependence on temperature and external electric fields.
Conclusions:
- Twisted bilayer graphene exhibits significantly decoupled layers due to rotation.
- Incoherent conduction is the primary transport mechanism between layers in twisted bilayer graphene.
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