Plasmonic Zener tunneling in binary graphene sheet arrays.

Area of Science:

• Condensed matter physics
• Plasmonics
• Nanophotonics

Background:

• Graphene exhibits unique electronic and optical properties, enabling novel plasmonic devices.
• Surface plasmon polaritons (SPPs) are light-matter interactions confined to surfaces, crucial for nanoscale optics.
• Zener tunneling (ZT) is a quantum mechanical phenomenon involving electron transitions across band gaps.

Purpose of the Study:

• To investigate plasmonic Zener tunneling (ZT) in arrays of coupled graphene sheet waveguides.
• To explore the tunability of ZT by controlling chemical potentials in graphene.
• To analyze the behavior of surface plasmon polaritons (SPPs) in engineered graphene structures.

Main Methods:

• Fabrication of graphene sheet waveguide arrays with alternating chemical potentials.
• Numerical simulations of SPP propagation and band structure analysis.
• Application of coupled-mode theory for theoretical analysis of tunneling rates.

Main Results:

• The single SPP band splits into two minibands due to alternating chemical potentials.
• ZT occurs at the edge of the Brillouin zone, facilitated by a linear gradient in the propagation constant.
• Simulated tunneling rates agree with coupled-mode theory predictions and are tunable via chemical potential differences.

Conclusions:

• Plasmonic Zener tunneling is achievable in graphene waveguide arrays.
• The tunneling rate can be precisely controlled by adjusting the chemical potential landscape.
• This work offers a pathway for developing tunable plasmonic devices based on graphene.