Modifying electronic and structural properties of 2D van der Waals materials via cavity quantum vacuum fluctuations: A first-principles QEDFT study

TL;DR

This study uses first-principles QEDFT to show how cavity vacuum fluctuations can modify the electronic, structural, and functional properties of 2D van der Waals materials, enabling tunable material characteristics.

Contribution

It demonstrates the universal impact of cavity photon fields on 2D materials' electronic density and properties, introducing a method to engineer material features via light-matter coupling.

Findings

Cavity photons induce localization of electronic density along polarization directions.

Band gaps in monolayer h-BN and 2H-MoS₂ can be tuned by cavity fields.

Interlayer spacing and related properties in bilayer 2H-MoS₂ and MoTe₂ are adjustable through light-matter interaction.

Abstract

Structuring the photon density of states and light-matter coupling in optical cavities has emerged as a promising approach to modifying the equilibrium properties of materials through strong light-matter interactions. In this article, we employ state-of-the-art quantum electrodynamical density functional theory (QEDFT) to study the modifications of the electronic and structural properties of two-dimensional (2D) van der Waals (vdW) layered materials by the cavity vacuum field fluctuations. We find that cavity photons modify the electronic density through localization along the photon polarization directions, a universal effect observed for all the 2D materials studied here. This modification of the electronic structure tunes the material properties, such as the shifting of energy valleys in monolayer h-BN and 2H-MoS$_2$, enabling tunable band gaps. Also, it tunes the interlayer spacing in bilayer 2H-MoS$_2$ and T$_\text{d}$-MoTe$_2$, allowing for adjustable ferroelectric, nonlinear Hall effect, and optical properties, as a function of light-matter coupling strength. Our findings open an avenue for engineering a broad range of 2D layered quantum materials by tuning vdW interactions through fluctuating cavity photon fields.