TY - JOUR A1 - Simin, D. A1 - Soltamov, V. A. A1 - Poshakinskiy, A. V. A1 - Anisimov, A. N. A1 - Babunts, R. A. A1 - Tolmachev, D. O. A1 - Mokhov, E. N. A1 - Trupke, M. A1 - Tarasenko, S. A. A1 - Sperlich, A. A1 - Baranov, P. G. A1 - Dyakonov, V. A1 - Astakhov, G. V. T1 - All-Optical dc Nanotesla Magnetometry Using Silicon Vacancy Fine Structure in Isotopically Purified Silicon Carbide JF - Physical Review X N2 - We uncover the fine structure of a silicon vacancy in isotopically purified silicon carbide (4H-\(^{28}\)SiC) and reveal not yet considered terms in the spin Hamiltonian, originated from the trigonal pyramidal symmetry of this spin-3/2 color center. These terms give rise to additional spin transitions, which would be otherwise forbidden, and lead to a level anticrossing in an external magnetic field. We observe a sharp variation of the photoluminescence intensity in the vicinity of this level anticrossing, which can be used for a purely all-optical sensing of the magnetic field. We achieve dc magnetic field sensitivity better than 100  nT/√Hz within a volume of 3×10\(^{−7}\)mm\(^3\) at room temperature and demonstrate that this contactless method is robust at high temperatures up to at least 500 K. As our approach does not require application of radio-frequency fields, it is scalable to much larger volumes. For an optimized light-trapping waveguide of 3  mm\(^3\), the projection noise limit is below 100  fT/√Hz. KW - condensed matter physics KW - optoelectronics KW - spintronics Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-147682 VL - 6 ER -