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Hubbard U and Hund's Exchange J in Transition Metal Oxides: Screening vs. Localization Trends from Constrained Random Phase Approximation by Vaugier, Loig; Jiang, Hong; Biermann, Silke is a scholarly article available to read on EtoBox.

What is Hubbard U and Hund's Exchange J in Transition Metal Oxides: Screening vs. Localization Trends from Constrained Random Phase Approximation about?

In this work, we address the question of calculating the local effective Coulomb interaction matrix in materials with strong electronic Coulomb interactions from first principles. To this purpose, we implement the constrained random phase approximation (cRPA) into a density functional code within the linearized augmented plane wave (LAPW) framework. We apply our approach to the 3d and 4d early transition metal oxides SrMO3 (M=V, Cr, Mn) and (M=Nb, Mo, Tc) in their paramagnetic phases. For these systems, we explicitly assess the differences between two physically motivated low-energy Hamiltonians: The first is the three-orbital model comprising the t2g states only, that is often used for early transition metal oxides. The second choice is a model where both, metal d- and oxygen p-states are retained in the construction of Wannier functions, but the Hubbard interactions are applied to the d-states only ("d-dp Hamiltonian"). Interestingly, since -- for a given compound -- both U and J depend on the choice of the model, so do their trends within a family of these compounds. In the 3d perovskite series SrMO3 the effective Coulomb interactions in the t2g Hamiltonian decrease along the se

Author

Vaugier, Loig; Jiang, Hong; Biermann, Silke

Published

2012

Language

EN