Artificial atom qubits in diamond have emerged as leading candidates for a range of solid-state quantum systems, from quantum sensors to repeater nodes in memory-enhanced quantum communication. Inversion-symmetric group IV vacancy centers, comprised of Si, Ge, Sn, and Pb dopants, hold particular promise as their neutrally charged electronic configuration results in a ground-state spin triplet, enabling long spin coherence above cryogenic temperatures. However, despite the tremendous interest in these defects, a theoretical understanding of the electronic and spin structure of these centers remains elusive. In this context, we predict the ground-state and excited-state properties of the neutral group IV color centers from first principles. We capture the product Jahn–Teller effect found in the excited state manifold to second order in electron–phonon coupling, and present a nonperturbative treatment of the effect of spin–orbit coupling. Importantly, we find that spin–orbit splitting is strongly quenched due to the dominant Jahn–Teller effect, with the lowest optically-active ³E_u state weakly split into m_s-resolved states. The predicted complex vibronic spectra of the neutral group IV color centers are essential for their experimental identification and have key implications for use of these systems in quantum information science.

钻石中的人造原子量子位元已经成为一系列固态量子系统的领先候选者，从量子传感器到内存增强型量子通信中的中继器节点。由Si，Ge，Sn和Pb掺杂物组成的IV型对称对称空位中心具有特殊的前景，因为它们的中性带电电子结构导致基态自旋三重态，使低温自旋相干长。然而，尽管对这些缺陷有极大的兴趣，但是对这些中心的电子和自旋结构的理论理解仍然难以捉摸。在这种情况下，我们根据第一个原理预测中性IV组色心的基态和激发态特性。我们捕获了在激发态流形中电子-声子耦合中二阶阶乘的乘积Jahn–Teller效应，并提出了自旋轨道耦合效应的非扰动处理。重要的是，我们发现由于占主导地位的Jahn-Teller效应，自旋轨道分裂被强烈淬灭，具有最低的光学活性³ E _u状态微弱地分解为m _s个已分解状态。中性IV族色中心的预测复杂振动光谱对于它们的实验识别是必不可少的，并且对于在量子信息科学中使用这些系统具有关键意义。