Relaxation processes and high-field coherent spin manipulation in color center ensembles in 6 H -SiC

Electron–Nuclear Coherent Coupling and Nuclear Spin Readout through Optically Polarized VB– Spin States in hBN

“…Remarkably, the V B – coherence in electron-irradiated sample is close to the 18 μs upper limit, theoretically predicted for spin defects in hBN using a cluster expansion method and assuming that decoherence is mainly caused by the entanglement between the electron spin and the nuclear spin bath of the host atoms . It is thus within the common range of the coherence for high-density spin defects in diamond , and SiC, , though well below the millisecond range established for single defects in these materials. , (ii) The observed stretched exponential decay indicates that the total coherence time, in addition to spin–spin relaxation, is determined by spectral diffusion, which is commonly characterized by a typical value of n between 1 and 4 depending on the regime of spectral diffusion . The latter indicates coherent interaction of the V B – defect spin with the random and temporally fluctuating local (effective) magnetic field associated with the dipolar-interaction induced flip-flops of nuclear spin pairs of 10 B, 11 B, and 14 N.…”

“…The 15 μs spin-coherence time directly measured via Hahn-echo decay is apparently longer than previously reported for the V B – spin ensemble in neutron-irradiated samples. It is thus within the common range of the coherence for high-density spin defects in diamond , and SiC , though well below the millisecond range established for single defects in these materials. , Given the 100% magnetic nuclei of the host material, the achieved coherence time is remarkable, suggesting that some decoherence-reducing effects are already active. These effects should be identified in near future work, in order to enhance them afterward.…”

Multi-photon multi-quantum transitions in the spin-3/2 silicon-vacancy centers of SiC

“…Apart from that, mature fabrication techniques exist for SiC. Here we focus on the silicon vacancies in the 6H-SiC polytype [9][10][11], where three types of Si vacancies have been identified, labelled V 1 , V 2 and V 3 , which correspond to different lattice positions [5,12,13]. It has been shown that siliconvacancies at hexagonal sites h corresponds to V 1 , while V 3 and V 2 are at cubic lattice sites k 1 and k 2 [14].…”

“…It has been shown that siliconvacancies at hexagonal sites h corresponds to V 1 , while V 3 and V 2 are at cubic lattice sites k 1 and k 2 [14]. When the vacancies are negatively charged (V − Si ) , they have spin 3/2 and the ground state spin sublevels can be polarized by optical irradiation [10,11]. In previous work, we measured relaxation rates and optical spin initialization of V − Si at room temperature [9,10], the polarization dependencies of the ZPLs and the ODMR contrast as a function of temperature [15].…”