$\textit{Ab initio}$ and group theoretical study of properties of the $\text{C}_\text{2}\text{C}_\text{N}$ carbon trimer defect in h-BN

Abstract

Hexagonal boron nitride (h-BN) is a promising platform for quantum information processing due to its potential to host optically active defects with attractive optical and spin properties. Recent studies suggest that carbon trimers might be the defect responsible for single-photon emission in the visible spectral range in h-BN. In this theoretical study, we combine group theory together with density functional theory (DFT) calculations to predict the properties of the neutral C2CN carbon trimer defect. We find the multi-electron states of this defect along with possible radiative and nonradiative transitions assisted by the spin-orbit and the spin-spin interactions. We also investigate the Hamiltonian for external magnetic field and ground-state hyperfine interactions. Lastly, we use the results of our investigation in a Lindblad master equation model to predict an optically detected magnetic resonance (ODMR) signal and the g 2 (τ ) correlation function. Our findings can have important outcomes in quantum information applications such as quantum repeaters used in quantum networks and quantum sensing.

Review on coherent quantum emitters in hexagonal boron nitride

“…Carbon trimer defects, in particular the C 2 C N -trimer, were investigated in detail by ab inito and group theory finding. For example, several radiative transitions together with spin-orbit and spin-spin assisted non-radiative transitions and a possible ODMR signal with a contrast of ≈ 1 % were found [79]. Defects involving a single negatively-charged boron vacancy (V − B ) emitting preferentially at 800 nm were discovered as spin defects with a spin S=1 [77] demonstrating ODMR [80,81,82,83] and rabi oscillations [84].…”