First-principles calculation of the Stark shift for the NV center in diamond

Point defects in semiconductors are promising candidates for several applications in quantum information sciences such as quantum computing, communication or sensing. Acting as single-photon sources, they provide the robust spin-photon interface needed for the distribution of entanglement in quantum networks. However, mechanical and electrical fluctuations in the vicinity of the defects will cause a shift of their optical zero-phonon-line (ZPL), an effect known as spectral diffusion. Spectral diffusion is a major technological issue in the deployment of high-performance quantum defects. Stark shift caused by stray electric field is usually considered as the main cause of spectral diffusion. Here, I will present the results of our density functional theory (DFT) calculations of the Stark shift on the negatively charged nitrogen-vacancy (NV) center in diamond. Using a slab model, we monitor the Stark shift by calculating the energy difference between the ground-state and the excited-state as a function of an applied electric field. We discuss the methodological challenges involved with charged slabs and compare our results with our own and previous computations using Modern theory of polarization. We discuss the advantages of the slab approach and issues with the Modern theory of polarization approach. We also compare the effect of different functionals including hybrids, compare to experimental data and provide a perspective of Stark shift computations on other quantum defects.