A Comparative Study of Electron Radiation Responses of Pu₂Zr₂O₇and La₂Zr₂O₇: An <i>Ab</i><i>Initio</i> Molecular Dynamics Study

• Main Authors: Shounuo Zhang, Menglu Li, Haiyan Xiao, Zijiang Liu, Xiaotao Zu
• Format: Article
• Language: English
• Published: MDPI AG 2021-03-01
• Series: Materials
• Subjects: pyrochlores; electron radiation; structural amorphization; ab initio molecular dynamics simulations
• Online Access: https://www.mdpi.com/1996-1944/14/6/1516
• ISSN: 1996-1944

In this study, the response of Pu₂Zr₂O₇and La₂Zr₂O₇to electronic radiation is simulated, employing an <i>ab initio</i> molecular dynamics method. It is shown that Pu₂Zr₂O₇ undergoes a crystalline-to-amorphous structural transition with 0.3% electronic excitation, while for La₂Zr₂O₇, 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 Pu₂Zr₂O₇ and La₂Zr₂O₇. The difference in responses to electron radiation between Pu₂Zr₂O₇ and La₂Zr₂O₇mainly results from the strong correlation effects between Pu 5<i>f</i> electrons and the smaller band gap of Pu₂Zr₂O₇. These results suggest that Pu₂Zr₂O₇ 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 Pu₂Zr₂O₇. The presented results will advance the understanding of the radiation damage effects of zirconate pyrochlores.