Carbon and silicon vacancies in electron-irradiated 6H-SiC

Defect-induced magnetism in neutron irradiated 6H-SiC single crystals

Defect-induced magnetism is firstly observed in neutron irradiated SiC single crystals. We demonstrated that the intentionally created defects dominated by divacancies (V(Si)V(C)) are responsible for the observed magnetism. First-principles calculations revealed that defect states favor the formation of local moments and the extended tails of defect wave functions make long-range spin couplings possible. Our results confirm the existence of defect-induced magnetism, implying the possibility of tuning the magnetism of wide band-gap semiconductors by defect engineering.

Identification of lattice vacancies on the two sublattices of SiC

The identification of atomic defects in solids is of pivotal interest for understanding atomistic processes and solid state properties. Here we report on the exemplary identification of vacancies on each of the two sublattices of SiC by making use of (i) electron irradiation, (ii) measurements of the positron lifetimes, (iii) coincident Doppler broadening studies of the positron-electron annihilation radiation, and (iv) a comparison of the experimental data with theoretical studies. After 0.3 MeV electron irradiation, carbon vacancies V(C) are identified, where, after 0.5 MeV electron irradiation, predomi-nantly silicon vacancies V(Si) are observed. After 2.5 MeV irradiation, divacancies V(Si)-V(Si) are detected. The present results are expected to be of general importance for reliable identification of defects and atomic processes in complex solids.