Y. Isobe et al., ADDITIVE ELEMENT EFFECTS ON ELECTRONIC CONDUCTIVITY OF ZIRCONIUM-OXIDE FILM, Journal of Nuclear Science and Technology, 31(6), 1994, pp. 546-551
A theoretical study on the electronic structure of zirconium oxide usi
ng a molecular orbital method was carried out to investigate the addit
ive element effects on the electronic conductivity of oxide film forme
d on Zr-alloys. The atomic clusters used were (MZr12O8)36+ (M = Zr, 3d
-transition metals and alkali metals). To simulate the electron conduc
tion process in the oxide, calculations for a cluster with oxygen vaca
ncy (Vo) were also carried out. The energy gap E(g) between electron-o
ccupied and empty levels was evaluated, and the electronic conductivit
y was estimated qualitatively. Opposite effects on the electronic cond
uctivity were found for additions of 3d-transition metals and alkali m
etals. The latter increased the electronic conductivity by forming imp
urity levels with small E(g). The former, however, induced compressive
strain in the oxide, resulting in a lowering of electronic conductivi
ty due to widening of the energy gap at the oxygen vacancy.