Ultrafast laser induces macroscopic symmetry-breaking of diamond color centers

The negatively charged nitrogen-vacancy center is a leading quantum platform due to its excellent spin coherence and stable interactions. Understanding its ultrafast dynamics is crucial for quantum applications but presents significant challenges for both experimental characterization and atomic-scale modeling. Here, we employ real-time time-dependent density functional theory to investigate the coupled electron-phonon-spin dynamics in negatively charged nitrogen-vacancy centers. Laser excitation promotes minority-spin electrons within 100 fs, establishing a C3v-symmetry breaking charge ordering. Subsequently, ionic motion on the potential energy surface of the excited electrons generates both symmetric oscillations of carbon-nitrogen bonds and dynamic Jahn-Teller distortions with a C3v-symmetry breaking. These distortions subsequently induce nonlocal coherent phonons in the diamond lattice, which propagate with the C3v-symmetry breaking at the sound velocity ( ~ 2 Å/fs). Our simulations provide direct time-resolved visualization of these processes, offering novel insights into the microscopic interplay of electrons, phonons, and spins in nitrogen-vacancy centers. The coupled electron-phonon-spin dynamics in diamond NV centers has been studied in pump-probe experiments, revealing distinct relaxation timescales. Here, the authors use real time time dependent density functional theory to provide a unified picture of the multistage dynamics in the NV center under ultrafast laser excitation.