First-principles study of energetic and electronic properties of A2Ti2O7 (A=Sm, Gd, Er) pyrochlore

First-principles calculations have been carried out to study the electronic properties of A(2)Ti(2)O(7) (A=Sm, Gd, Er) pyrochlores. It was found that f electrons have negligible effect on the structural and energetic properties, but have significant effect on the electronic properties. Density of state analysis shows that A-site 4f electrons do take part in the chemical bonding. Also, we found that < Gd-O(48f)> bond is less covalent than < Sm-O(48f)> and < Er-O(48f)> bonds, while < Ti-O(48f)> bond in Gd(2)Ti(2)O(7) is more covalent. It was proposed that for A(2)Ti(2)O(7) (A=Sm, Gd, Er) pyrochlores, < Ti-O(48f)> bonds may play more significant role in determining their radiation resistance to amorphization. (c) 2008 American Institute of Physics. [DOI:10.1063/1.2986156]