A Comparative Study of Electron Radiation Responses of Pu(2)Zr(2)O(7) and La(2)Zr(2)O(7): An ab initio Molecular Dynamics Study

In this study, the response of Pu(2)Zr(2)O(7) and La(2)Zr(2)O(7) to electronic radiation is simulated, employing an ab initio molecular dynamics method. It is shown that Pu(2)Zr(2)O(7) undergoes a crystalline-to-amorphous structural transition with 0.3% electronic excitation, while for La(2)Zr(2)O(7), the structural amorphization occurs with 1.2% electronic excitation. During the microstructural evolution, the anion disorder further drives cation disorder and eventually results in the structural amorphization of Pu(2)Zr(2)O(7) and La(2)Zr(2)O(7). The difference in responses to electron radiation between Pu(2)Zr(2)O(7) and La(2)Zr(2)O(7) mainly results from the strong correlation effects between Pu 5f electrons and the smaller band gap of Pu(2)Zr(2)O(7). These results suggest that Pu(2)Zr(2)O(7) is less resistant to amorphization under local ionization rates that produce a low level of electronic excitation, since the level of the concentration of excited electrons is relatively low in Pu(2)Zr(2)O(7). The presented results will advance the understanding of the radiation damage effects of zirconate pyrochlores.