Strain and dopant-induced band-gap formation in metastable ZrO: resolving the experiment-simulation discrepancy
Junting Zhang, Susannah Lea, Johannes Lischner, Andrew Horsfield, Mark Wenman
The uranium dioxide fuel in nuclear reactors is used in the form of stacks of ceramic fuel pellets. These pellets are sealed in zirconium alloy tubes to protect them and prevent fission product release. The zirconium can react with the surrounding water to form an outer layer of zirconium oxide (ZrO2). The region between the metal and the oxide is not well understood but appears to include a different oxide of zirconium (ZrO). As ZrO is not stable it is hard to study by means of experiment, so here we employ computer calculations.
We use a series of computational methods of increasing accuracy to evaluate the energy needed to excite electrons to make them mobile (the energy gap). We find that both compressing the ZrO and adding Sn can increase the value of the energy gap.