Structural, electronic properties with different terminations for fluorapatite (001) surface: A first-principles investigation

• Published in: Computational materials science 2017-01, Vol.126, p.132-138
• Main Authors: Qiu, Yue-Qin, Cui, Wei-Yong, Li, Long-Jiang, Ye, Jun-Jian, Wang, Jie, Zhang, Qin
• Format: Article
• Language: English
• Subjects: Charge distribution; Density functional theory; Density-functional theory (DFT); Displacement; Electronic structure; Fluorapatite; Mathematical analysis; Movements; Surface energy; Terminations
• ISSN: 0927-0256; 1879-0801
• DOI: 10.1016/j.commatsci.2016.09.027

[Display omitted] •The major displacement of the Ca atom in the Ca layer is along the z-axis direction.•The Ca-middle termination has the lowest surface energy (0.793J/m2).•The CaO bonds in the surface are more susceptible. The Ca-rich, Ca-middle and PO4-rich terminations of fluorapatite (001) surface have been investigated with first-principles calculations based on density functional theory (DFT). Results show that the major displacement of the Ca atom in the Ca layer is along the z-axis direction, while these atoms in the Ca3(PO4)3F layer show more lateral movements in the (001) plane, especially for the Ca-middle and PO4-rich terminations. The Ca-middle termination has the lowest surface energy (0.793J/m2), and is more similar to the bulk in charge distribution. These bonds near the surface appear to be mainly contractive, which indicates that they are strengthened after the relaxation. The CaO bonds are more susceptible during the redistribution of the charge in the surface. Further analysis shows that the interactions in the Ca-rich termination are not as strong as that of the Ca-middle and PO4-rich terminations.