Carbon-contaminated topological defects in hBN: a potential new class of single photon emitters

Topological defects, such as Stone-Wales defects and grain boundaries, are common in 2D materials. In this exploratory study, we investigate the intricate interplay of carbon contamination and topological defects revealing a new class of color centers in hexagonal boron nitride. We demonstrate that carbon contamination and strain can both stabilize Stone-Wales configurations with desirable optical properties. Inspired by these results, we further demonstrate that carbon atoms at grain boundaries can resolve energetic B-B and N-N bonds and give rise to highly favorable atomic structures potentially leading to the accumulation of carbon contamination at grain boundaries. We identify carbon-contaminated topological defects that give rise to color centers emitting in the visible spectral range with short radiative lifetime and high Debye-Waller factors. Our discoveries shed light on a new class of defects and pave the way towards the identification of color centers and single photon emitters in hBN.