So-called V-centers of several types were studied for the first time, in SrS polycrystals, by using electron paramagnetic resonance. Isolated cation vacancies, and their complexes with other defects, were formed during plastic deformation and were further transformed by ionic processes during annealing. They became paramagnetic when the samples were irradiated with X-rays at 77K, and a hole was captured by an S2- ion situated next to a cation vacancy. Therefore, V- centers arose from isolated cation vacancies, vc, VSH from vc - (SH)- complexes and V2(SH)+ from (SH)- - vc - (SH)- complexes. The captured holes were released from V centers at below room temperature, over a very wide temperature range. The electric fields of the dislocations were supposed to modify the activation energies for hole release. The low activation temperatures of ionic processes (as compared with the ionic conductivity of undamaged SrS) indicated that defects were transported by dislocations in plastically deformed material.

V Centers in Plastically Deformed SrS. V.Seeman, M.Danilkin, M.Must, A.Ots, L.Pung: Physica Status Solidi B, 2003, 238[1], 102-9