Ultrafast nonthermal NV center formation in diamond

NV color centers in diamond exhibit a variety of interesting properties which make them suitable for different technological applications, like quantum sensing, secure message encryption and biological imaging. They can also be used as qubits. In order to construct arrays of NV centers for quantum computing, it is necessary to maximize interqubit interactions and, at the same time, minimize all sources of decoherence. This could possibly be achieved by using femtosecond-laser pulses in the production process. In this work, we performed ab initio atomistic simulations to study ultrafast nonthermal NV center formation in diamond induced by excitation through femtosecond-laser pulses. Our results indicate that the interatomic bonding properties can be modified by the excitation in such a way that a vacancy and a nitrogen impurity, initially not nearest neighbors, attract themselves and form a NV center within 250 fs after the excitation. In contrast to the thermal behavior, here, the nitrogen atom starts to oscillate nonthermally between two grid points after the excitation. For comparison to the thermal case we performed a single run in which a NV center is thermally formed at T=1500 K in one of our supercells. [Display omitted]