Combining density functional theory with macroscopic QED for quantum light-matter interactions in 2D materials

Area of Science:

• Quantum optics
• Materials science
• Condensed matter physics

Background:

• Modeling quantum light-matter interactions in ultrathin materials presents challenges in accounting for confined plasmonic modes, quantization, losses, and electronic states.
• Accurate theoretical frameworks are crucial for understanding and predicting phenomena like Purcell enhancement in nanoscale systems.

Purpose of the Study:

• To develop a quantitative and predictive theory for quantum light-matter interactions in ultrathin materials.
• To investigate Purcell enhancements in few-layer transition metal dichalcogenides using a first-principles approach.

Main Methods:

• Combining density functional theory (DFT) with macroscopic quantum electrodynamics.
• Simultaneously modeling ultra-confined plasmonic modes, quantization, losses, and electronic states.
• Applying the framework to intersubband transitions in few-layer transition metal dichalcogenides.

Main Results:

• Achieved Purcell enhancements up to 10^7 for intersubband transitions.
• Demonstrated the importance of wave function choice in theoretical models.
• Quantitatively tested common approximation paradigms like the dipole approximation and Fermi's Golden rule.

Conclusions:

• The developed DFT-based macroscopic quantum electrodynamics framework provides a robust method for studying light-matter interactions in nanostructured materials.
• This work lays the foundation for ab initio-based quantum treatments of realistic nanophotonic systems.
• Highlights the critical role of accurate electronic state descriptions in quantum optical phenomena.