Defect stability in thorium monocarbide：An ab initio study

• Published in: Chinese physics B Vol. 24; no. 9; pp. 424 - 429
• Main Author: 王昌英 韩晗 邵宽 程诚 怀平
• Format: Journal Article
• Language: English
• Published: 01.09.2015
• Subjects: Carbon; Defects; Dimers; Elastic constants; Interstitial defects; Point defects; Thorium; Vacancies; 从头算; 密度泛函理论; 弹性性能; 点缺陷; 碳化; 稳定性; 空位缺陷; 钍
• ISSN: 1674-1056; 2058-3834; 1741-4199
• DOI: 10.1088/1674-1056/24/9/097101

The elastic properties and point defects of thorium monocarbide（ThC） have been studied by means of density functional theory based on the projector-augmented-wave method. The calculated electronic and elastic properties of ThC are in good agreement with experimental data and previous theoretical results. Five types of point defects have been considered in our study, including the vacancy defect, interstitial defect, antisite defect, schottky defect, and composition-conserving defect. Among these defects, the carbon vacancy defect has the lowest formation energy of 0.29 eV. The second most stable defect（0.49 eV） is one of composition-conserving defects in which one carbon is removed to another carbon site forming a C2 dimer. In addition, we also discuss several kinds of carbon interstitial defects, and predict that the carbon trimer configuration may be a transition state for a carbon dimer diffusion in Th C.