Ab initio theory of intersystem crossings in diamond nitrogen-vacancy qubit

Pengfei Wang, Fazhan Shi, Du Jiangfeng

Sangkook Choi, Manish Jain, Steven G. Louie

Optical initialization of the negatively charged nitrogen-vacancy (NV${}^{\ensuremath{-}}$) center in diamond makes it one of the best candidates for realization of addressable spins in the solid state for quantum computing and other studies. However, its exact mechanism was not clear. We show that exact diagonalization of a many-electron Hamiltonian with parameters derived from ab initio GW calculations puts strong constraints on the mechanism. The energy surfaces of the low-energy many-body states and the relaxation processes of photoexcitation responsible for the optical initialization are calculated. Intersystem crossings are shown to be essential.

Sangkook Choi, Manish Jain, Steven G. Louie

Optical initialization of the negatively charged nitrogen-vacancy (NV − ) center in diamond makes it one of the best candidates for realization of addressable spins in the solid state for quantum computing and other studies. However, its exact mechanism was not clear. We show that exact diagonalization of a many-electron Hamiltonian with parameters derived from ab initio GW calculations puts strong constraints on the mechanism. The energy surfaces of the low-energy many-body states and the relaxation processes of photoexcitation responsible for the optical initialization are calculated. Intersystem crossings are shown to be essential.

Pronoy Das, Agam Verma, Parvinder Solanki +4 more

Emre Togan, Yiwen Chu, Alexei S. Trifonov +6 more

Michael Goldman, Marcus W. Doherty, Alp Sipahigil +5 more

Motivated by recent measurements of state-selective intersystem crossing (ISC) in the nitrogen-vacancy (NV) center in diamond (see companion PRL), a new microscopic model is developed of the key ISC mechanism. These nonradiative transitions between states of different spin multiplicity are pivotal in the optical initialization and readout of the NV center's electronic spin, which has created a diverse range of room-temperature applications in metrology and quantum information science.