Highly Tunable Interlayer Coupling and Electronic Structures of Few-Layer Graphene with Pressure.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Solid-State Physics

Background:

• Interlayer electronic coupling dictates the electronic properties of multi-layered graphene systems.
• Understanding this coupling is crucial for tuning electronic structure and phenomena like moiré potentials.

Purpose of the Study:

• To investigate the effect of external pressure on interlayer electronic coupling in few-layer graphene.
• To quantify the pressure-induced changes in the interlayer transfer integral (hopping parameter).

Main Methods:

• Infrared spectroscopy was used to observe resonance peak shifts in 2-10 layer graphene under pressure.
• A model based on the Morse potential was employed to correlate pressure with the transfer integral.

Main Results:

• A moderate pressure of approximately 3.5 GPa resulted in an almost 40% increase in the interlayer transfer integral.
• The resonance peak shift in infrared spectra directly indicated enhanced electronic coupling.

Conclusions:

• External pressure is an effective means to tune the electronic coupling in few-layer graphene.
• The established relationship between pressure and the transfer integral offers fundamental insights into interlayer interactions.