Nuclear-spin relaxation in solid-state-defect quantum bits via electron-phonon coupling in the optically excited state
Phys. Rev. Applied 24, 044027 – Published 9 October, 2025
DOI: https://doi.org/10.1103/1q3f-7zvl
Abstract
Optically accessible solid-state-defect spins serve as a primary platform for quantum information processing, where precise control of the electron spin and ancillary nuclear spins is essential for operation. With use of the nitrogen-vacancy color center in diamond as an example, by a combined group theory and density functional theory study we demonstrate that spin-lattice relaxation of the nuclear spin is significantly enhanced due to strong entanglement with orbital degrees of freedom in the optically excited state of the defect. This mechanism is common to other solid-state-defect nuclear spins with similar optically excited states. Additionally, we propose a straightforward and versatile ab initio scheme for predicting orbital-dependent spin Hamiltonians for trigonal defects exhibiting orbital degeneracy.