Radiative properties of quantum emitters in boron nitride from excited state calculations and Bayesian analysis

TL;DR

This study combines ab initio calculations and Bayesian analysis to characterize the excited states and radiative properties of defects in hexagonal boron nitride, aiding the identification of quantum emitters.

Contribution

It provides a comprehensive computational framework for analyzing defect emitters in 2D materials and predicts specific defect structures matching experimental data.

Findings

Wide variability in emission energies and lifetimes across defects

Identification of native V_NN_B defect as a likely quantum emitter

Development of a Bayesian approach for defect characterization

Abstract

Point defects in hexagonal boron nitride (hBN) have attracted growing attention as bright single-photon emitters. However, understanding of their atomic structure and radiative properties remains incomplete. Here we study the excited states and radiative lifetimes of over 20 native defects and carbon or oxygen impurities in hBN using ab initio density functional theory and GW plus Bethe-Salpeter equation calculations, generating a large data set of their emission energy, polarization and lifetime. We find a wide variability across quantum emitters, with exciton energies ranging from 0.3 to 4 eV and radiative lifetimes from ns to ms for different defect structures. Through a Bayesian statistical analysis, we identify various high-likelihood defect emitters, among which the native $\mathrm{V_NN_B}$ defect is predicted to possess emission energy and radiative lifetime in agreement with experiments. Our work advances the microscopic understanding of hBN single-photon emitters and introduces a computational framework to characterize and identify quantum emitters in 2D materials.