Electronic Structure Calculations of A2Ti2O7(A = Dy, Ho, and Y)

Abstract

Ab initiocalculations have been performed on titanate pyrochlores A2Ti2O7(A = Dy, Ho, and Y) to investigate their electronic structures. The generalized gradient approximation (GGA) +Uformalism has been used to correct the strong onsite Coulomb repulsion between the localized 4f electrons. The effects of effectiveUvalues on the structural and electronic properties of A2Ti2O7(A = Dy, Ho, and Y) have been discussed. It is shown that Dy2Ti2O7and Ho2Ti2O7exhibit different electronic structures from Y2Ti2O7. The strong interaction between Dy and Ho 4f electrons and O 2p orbitals may increase the covalency of〈Dy–O〉and〈Ho–O〉bonds and decrease their irradiation resistance.