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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 15: Postersession KFM

KFM 15.9: Poster

Donnerstag, 19. März 2020, 16:00–18:30, P2/1OG

NV-center formation after femtosecond-laser pulse excitation — •Marie Kempkes, Tobias Zier, and Martin E. Garcia — Theoretische Physik, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany

Recent studies showed that colour centers, like, NV-centers in diamond are a promising candidate for technological applications, since they could operate as single-photon emitter in the visible range. Unfortunately, due the fabrication process of NV-centers by artificial growth or ion bombardment the number of NV-centers is not well defined and not sufficiently controllable. Another disadvantage is the fact, that the sample has to be heated intensively in order to increase the vacancy and nitrogen mobility, which is necessary that NV-centers can form anyway. During this heating process other defects could appear within the crystalline structure that could decrease the efficiency of the NV-center. Therefore, we simulated the formation of a NV-center driven by femtosecond-laser excitation by ab initio methods. For this we first performed ab initio molecular dynamics simulations of diamond with a defect density of 3.1% and analyzed their impact on ultrafast phenomena, like, nonthermal melting and thermal phonon squeezing. We used this knowledge to perform simulations of the case that the nitrogen atom and the vacancy were not nearest neighbours in the beginning. Our results indicate, that femtosecond-laser pulses could be used to controllably produce NV-centers nonthermally on a timescale less than 200 fs with smallest possible impact on the surrounding crystal.