Razinkovas, LukasDoherty, MarcusManson, NeilWalle, Chris G. Van deAlkauskas, A.2023-04-112023-04-112469-9950http://hdl.handle.net/1885/288527We present a theoretical study of vibrational and vibronic properties of a point defect in the dilute limit by means of first-principles density functional theory calculations. As an exemplar we choose the negatively charged nitrogen-vacancy (NV) center, a solid-state system that has served as a testbed for many protocols of quantum technology. We achieve low effective concentrations of defects by constructing dynamical matrices of large supercells containing tens of thousands of atoms. The main goal of the paper is to calculate luminescence and absorption lineshapes due to coupling to vibrational degrees of freedom. The coupling to symmetric a1 modes is computed via the Huang-Rhys theory. Importantly, to include a nontrivial contribution of e modes we develop an effective methodology to solve the multimode E - e Jahn-Teller problem. Our results show that for NV centers in diamond a proper treatment of e modes is particularly important for absorption. We obtain good agreement with experiment for both luminescence and absorption. Finally, the remaining shortcomings of the theoretical approach are critically reviewed. The presented theoretical approach will benefit identification and future studies of point defects in solids.This work has received funding from the European Union's Horizon 2020 research and innovation program under Grant No. 820394 (project ASTERIQS). C.G.V.d.W. was supported by the National Science Foundation (NSF) through Enabling Quantum Leap: Convergent Accelerated Discovery Foundries for Quantum Materials Science, Engineering and Information (Q-AMASE-i) (Grant No. DMR-1906325). A.A. acknowledges the NSF Materials Research Science and Engineering Centers Program (Grant No. DMR-1720256) (Seed), and NSF Q-AMASE-i (Grant No. DMR-1906325) for funding visits to the University of California. Computational resources were provided by the High Performance Computing Center “HPC Saulėtekis” in the Faculty of Physics, Vilnius University; the Extreme Science and Engineering Discovery Environment, which is supported by the NSF (Grant No. ACI-1548562); and the National Computational Infrastructure, which is supported by the Australian Governmentapplication/pdfen-AU© 2021 The authors202110.1103/PhysRevB.104.0453032022-01-23