A new spin one defect in cubic SiC

Abstract After fast neutron irradiation with a dose of 10 19  cm −2 a new defect, labeled Ky5, has been revealed in the EPR spectra in addition to the dominant spectrum of the negatively charged silicon vacancy, the T1 center. Angular variation of the Ky5 spectrum indicates its origin from a spin S =1 defect. This spectrum can be detected in darkness in the whole temperature range 4.2–295 K with practically unchanged parameters confirming a triplet ground state of the Ky5 center. Its spin Hamiltonian parameters are isotropic g =2.003 and axially symmetric D tensor aligned along 〈1 1 1〉 crystal directions, D =443×10 −4  cm −1 . The angular dependence of the hyperfine structure could not be analyzed for the Ky5 center due to its relatively broad EPR linewidths, about 0.67 mT. Three times narrower lines are observed at about half-field range representing forbidden Δ M S =2 EPR transitions where hyperfine splittings are found for some crystal directions. Based on the symmetry and closeness with spin Hamiltonian parameters in 4H-SiC and 6H-SiC the Ky5 center has been tentatively assigned to the neutral divacancy in cubic SiC.