A linear response approach to determine Hubbard U and its application to evaluate properties of Y2B2O7, B = transition metals 3d, 4d and 5d

First-principles calculations were conducted to examine the properties of complex pyrochlore oxides, using the Y2B2O7 pyrochlore oxides (B-Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Tc, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt) as a representative group. Hubbard U correction was involved in the calculations and a linear response approach was employed to determine the U values of the d-orbitals of the transition-metal elements. The application of U correction was demonstrated to notably improve prediction of structural properties (e.g., lattice parameter), electronic properties (e.g., bandgap and magnetic moment) and phonon frequencies of the pyrochlore oxides. The present study confirms the necessity of U correction in first-principles studies of pyrochlore oxides and provides essential data for future computational investigation of complex oxide systems. (C) 2018 Elsevier B.V. All rights reserved.