Effective Coulomb interaction in transition metals from constrained random-phase approximation

TL;DR

This paper calculates the effective Coulomb interaction (U) in transition metals using a new parameter-free constrained random-phase approximation, revealing how U varies with structure and electron filling, and discussing correlation effects.

Contribution

It introduces a novel parameter-free method to compute U in transition metals using Wannier functions within the full-potential linearized augmented-plane-wave framework.

Findings

U values range from 1.5 to 5.7 eV depending on conditions.

U depends on crystal structure, spin polarization, and d-electron filling.

Discussion of electronic correlation strength and magnetic instability in 3d metals.

Abstract

The effective on-site Coulomb interaction (Hubbard $U$) between localized \textit{d} electrons in 3\textit{d}, 4\textit{d}, and 5\textit{d} transition metals is calculated employing a new parameter-free realization of the constrained random-phase approximation using Wannier functions within the full-potential linearized augmented-plane-wave method. The $U$ values lie between 1.5 and 5.7 eV and depend on the crystal structure, spin polarization, \textit{d} electron number, and \textit{d} orbital filling. On the basis of the calculated $U$ parameters, we discuss the strength of the electronic correlations and the instability of the paramagnetic state towards the ferromagnetic one for 3\textit{d} metals.