Strain-Induced Plasmon Confinement in Polycrystalline Graphene.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Nanotechnology

Background:

• Terahertz (THz) spectroscopy probes electronic intraband conductivity in materials like graphene.
• The Drude-Smith model is commonly used to describe conductivity in disordered systems.
• Understanding the link between microscopic structure and macroscopic conductivity is crucial for materials design.

Purpose of the Study:

• To investigate the impact of isotropic strain on the THz conductivity of polycrystalline graphene.
• To connect phenomenological conductivity models (Drude-Smith) with microscopic behavior using atomistic simulations.
• To elucidate the mechanisms behind strain-induced conductivity changes in graphene.

Main Methods:

• Utilizing Terahertz (THz) spectroscopy to measure the conductivity response of strained polycrystalline graphene.
• Employing a fully atomistic computational approach to simulate and fit the experimental THz data.
• Analyzing the relationship between Drude-Smith model parameters and microscopic structural features.

Main Results:

• Demonstrated a clear correlation between Drude-Smith parameters and the microscopic behavior of strained graphene.
• Showed that strain-induced conductivity changes primarily result from increased separation between single-crystal grains.
• Observed enhanced localization of plasmon excitations due to increased grain separation under strain.
• Identified that at low strain values, individual grain deformation influences conductivity.

Conclusions:

• Strain in polycrystalline graphene significantly influences conductivity by modifying inter-grain spacing and plasmon localization.
• Atomistic simulations provide a powerful tool to bridge the gap between macroscopic conductivity models and microscopic material properties.
• The findings offer insights into tailoring the electronic properties of graphene through controlled strain engineering.