Jahn-Teller Effects in Group IV Quantum Defects in Diamond*

Defects in diamond are leading solid-state candidates for a range of quantum technologies. Recent research has focused on identifying new color centers with properties that reach beyond the limitations of the well-known nitrogen-vacancy (NV^-) center. Group IV-vacancy centers have been a primary focus due to their symmetry-protected optical transitions and long-lived spin degree of freedom. A detailed understanding of the electronic structure of these emitters is paramount to their use in spin-photon systems. Here we detail the ground- and excited-state properties of the negative and neutral group IV color centers using first-principles methods. In particular, we outline the dynamic and product Jahn-Teller (pJT) effects expected in these defect systems, including their potential impact on zero phonon line energetics and spin-orbit coupling. We capture the interplay of spin-orbit and electron-phonon coupling in order to accurately describe the pJT-affected excited state manifold. These results provide a more accurate benchmark for comparison with experiment, especially for the group IV neutral centers, where many open questions remain.