Modeling the Zero-Phonon Line of Strained SnV Centers in Diamond; Including Reflections on Computational Cost and Accuracy

Among the group-IV vacancy color centers in diamond, the SnV holds promise for photonics based quantum applications. In this work, the Tin-Vacancy (SnV) zero-phonon line (ZPL) and its pressure coefficient are calculated using first principles approaches. The predicted absolute ZPL position is shown to be strongly influenced by the method and supercell size used. The results are therefore extrapolated to the dilute limit allowing for direct comparison with experiments. The importance of identifying the color-center related Kohn–Sham states is highlighted, as well as the shifting of these states due to electron excitations as well as supercell size and k-point position. In contrast to the absolute ZPL positions, the relative position of the SnV${}^0$ ZPL is consistently redshifted about $43$ nm compared to the SnV${}^{-}$ ZPL. In addition, the pressure coefficient is shown to be very robust over different methods, always resulting in a value of about $1.4$ nm/GPa, for both SnV${}^0$ and SnV${}^{-}$. Finally, the computational accuracy and cost are put into perspective.