Moiré-Induced Transport in CVD-Based Small-Angle Twisted Bilayer Graphene

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Twistronic devices based on 2D materials require precise control over twist angle and interface quality for optimal performance.
• Current methods like mechanical exfoliation face challenges in scalability and homogeneity.
• Chemical Vapor Deposition (CVD) offers a potential route for large-scale synthesis of high-quality 2D materials.

Purpose of the Study:

• To investigate the feasibility of using CVD-grown graphene single-crystals for assembling small-angle twisted bilayer graphene.
• To assess the transport properties and identify moiré-induced phenomena in such assembled structures.
• To establish CVD-based twisted bilayer graphene as a viable platform for fundamental studies and future device applications.

Main Methods:

• Assembly of small-angle twisted bilayer graphene from separated CVD-grown graphene single-crystals.
• Low-temperature dual-gated magnetotransport measurements.
• Analysis of transport signatures indicative of moiré superlattice formation and interlayer coupling.

Main Results:

• Demonstration of high-quality transport properties in CVD-assembled twisted bilayer graphene.
• Observation of a device-scale-uniform moiré potential at a twist angle of 2.4°.
• Evidence of tunable interlayer coupling, reduced Fermi velocity, large interlayer capacitance, and density-independent Brown-Zak oscillations.

Conclusions:

• CVD-based twisted bilayer graphene is a viable alternative to exfoliated flakes for fundamental research in twistronics.
• The scalable assembly technique ensures high-quality interfaces and twist-angle homogeneity necessary for advanced 2D devices.
• This work serves as a proof-of-concept for the future large-scale assembly of functional twistronic devices.