Hexagonal boron nitride (hBN) has recently emerged as a fascinating platform for room-temperature quantum photonics due to the discovery of robust visible light single-photon emitters. In order to utilize these emitters, it is necessary to have a clear understanding of their atomic structure and the associated excitation processes that give rise to this single photon emission. Here we perform density-functional theory (DFT) and constrained DFT calculations for a range of hBN point defects in order to identify potential emission candidates. By applying a number of criteria on the electronic structure of the ground state and the atomic structure of the excited states of the considered defects, and then calculating the Huang-Rhys (HR) factor, we find that the CBVN defect, in which a carbon atom substitutes a boron atom and the opposite nitrogen atom is removed, is a potential emission source with a HR factor of 1.66, in good agreement with the experimental HR factor. We calculate the photoluminescence (PL) line shape for this defect and find that it reproduces a number of key features in the the experimental PL lineshape.
@article{arxiv.1705.05753,
title = {First principles investigation of quantum emission from hBN defects},
author = {Sherif Abdulkader Tawfik and Sajid Ali and Marco Fronzi and Mehran Kianinia and Toan Trong Tran and Catherine Stampfl and Igor Aharonovich and Milos Toth and Michael J. Ford},
journal= {arXiv preprint arXiv:1705.05753},
year = {2017}
}