Proof of the thermodynamical stability of the E' center in SiO2.
The E' center is a paradigmatic radiation-induced defect in SiO2 whose peculiar EPR and hyperfine activity has been known for over 40 years. This center has been traditionally identified with a distorted, positively charged oxygen vacancy V(+)O. However, no direct proof of the stability of this defect has ever been provided, so that its identification is still largely incomplete. Here we prove directly that distorted V(+)O is metastable and that it satisfies the key requirements for its identification as E', such as thermal and optical response, and activation-deactivation mechanisms.
Carbonaro
C M
CM
INFM and Dipartimento di Fisica, Università di Cagliari, Cittadella Universitaria, I-09042 Monserrato, CA, Italy.
Fiorentini
V
V
Bernardini
F
F