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

TL;DR

This paper develops a comprehensive ab initio framework combining density functional theory with macroscopic QED to accurately model quantum light-matter interactions in ultra-thin 2D materials, enabling precise predictions of phenomena like Purcell enhancement.

Contribution

It introduces a novel methodology integrating DFT with macroscopic QED, allowing for realistic, first-principles modeling of quantum light-matter interactions in 2D nanostructures.

Findings

Purcell enhancement up to 10^7 for intersubband transitions

Validation of the methodology against common approximations

Importance of wave function choice in modeling

Abstract

A quantitative and predictive theory of quantum light-matter interactions in ultra thin materials involves several fundamental challenges. Any realistic model must simultaneously account for the ultra-confined plasmonic modes and their quantization in the presence of losses, while describing the electronic states from first principles. Herein we develop such a framework by combining density functional theory (DFT) with macroscopic quantum electrodynamics, which we use to show Purcell enhancements reaching $10^7$ for intersubband transitions in few-layer transition metal dichalcogenides sandwiched between graphene and a perfect conductor. The general validity of our methodology allows us to put several common approximation paradigms to quantitative test, namely the dipole-approximation, the use of 1D quantum well model wave functions, and the Fermi's Golden rule. The analysis shows that the choice of wave functions is of particular importance. Our work lays the foundation for practical ab initio-based quantum treatments of light matter interactions in realistic nanostructured materials.