Excitons in hexagonal boron nitride single-layer: a new platform for polaritonics in the ultraviolet

TL;DR

This study uses advanced first-principles calculations to explore the excitonic and optical properties of 2D hexagonal boron nitride, demonstrating its potential for ultraviolet polaritonics and near-perfect UV mirrors.

Contribution

It provides detailed excitonic property predictions for 2D hBN using GW and BSE methods, and shows its suitability for UV polaritonics and mirror applications.

Findings

2D hBN has a large excitonic binding energy.

Single-layer hBN can act as an almost perfect UV mirror.

Good agreement between different theoretical approaches.

Abstract

The electronic and optical properties of 2D hexagonal boron nitride are studied using first principle calculations. GW and BSE methods are employed in order to predict with better accuracy the excited and excitonic properties of this material. We determine the values of the band gap, optical gap, excitonic binding energies and analyse the excitonic wave functions. We also calculate the exciton energies following an equation of motion formalism and the Elliot formula, and find a very good agreement with the GW+BSE method. The optical properties are studied for both the TM and TE modes, showing that 2D hBN is a good candidate to polaritonics in the UV range. In particular it is shown that a single layer of h-BN can act as an almost perfect mirror for ultraviolet electromagnetic radiation.