Excitonic circular dichroism in boron-nitrogen cluster decorated graphene

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Information

Background:

• Graphene's unique electronic properties make it a candidate for advanced electronic devices.
• Valleytronics aims to utilize electron valley degrees of freedom for information processing.
• Controlling valley polarization is crucial for valleytronics applications.

Purpose of the Study:

• To theoretically investigate a boron and nitrogen cluster incorporated graphene system.
• To explore its potential for efficient valley polarization and related phenomena.
• To assess its suitability for quantum information processing.

Main Methods:

• First-principles calculations were employed to model the material system.
• The GW approximation was used to account for excitonic quasiparticles.
• Many-body Bethe-Salpeter equation calculations were performed to determine optical properties.

Main Results:

• The proposed system exhibits broken spatial inversion symmetry, leading to high Berry curvature.
• An optical gap of 1.72 eV and excitonic binding energy of 0.65 eV were calculated.
• Negligible intervalley scattering allows selective excitation of electrons in opposite valleys via circularly polarized light.

Conclusions:

• The boron and nitrogen-doped graphene system demonstrates potential for efficient valley polarization.
• The material can exhibit the circular-dichroism valley Hall effect under an electric field.
• Excitonic qubits in this system could be utilized for advanced information processing.