부산대학교 도서관

A systematic density functional theory study is performed to investigate the lattice parameters, the internal positional parameter and bond length of RE2Sn2O7(RE = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) pyrochlores. To analyze the structural stability in extreme conditions and verify whether bond strength varies inversely to bond length in rare-earth stannate pyrochlores, the structural parameter and bonding strength under hydrostatic pressure are studied. The tight connection between the different bond length contraction and the variation of 48 oxygen positional parameter is also discovered. We calculated the bond length and the bulk modulus of RE2Sn2O7 and found that the RE-O bond plays a predominant role in determining the bulk modulus. Meanwhile, the present calculations suggest that the 'bimodal effect' also exists in rare-earth stannate pyrochlores. [ABSTRACT FROM AUTHOR]