Does hybrid density functional theory predict a non-magnetic ground state for -Pu?

Physics Department, University of Texas at Arlington - Arlington, TX 76019, USA

Corresponding author: akr@uta.edu

Received: 4 August 2008
Accepted: 11 December 2008

Abstract

Hybrid density functionals, which replace a fraction of density functional theory (DFT) exchange with exact Hartree-Fock (HF) exchange, have been used to study the structural, magnetic, and electronic properties of -Pu. The fractions of exact Hartree-Fock exchange used were 25%, 40%, and 55%. Compared to the pure PBE functional, the lattice constants expanded with respect to the experimental value when the PBE-HF hybrid functionals were applied. For pure PBE and hybrid functionals with HF exchanges amounts of 25% and 40%, the ground state structure was anti-ferromagnetic, while for 55% HF contribution the ground state was non-magnetic. The electrons tend to exhibit slight delocalization or itinerancy for the pure PBE functional and well-defined localization for the hybrid functionals, with the degree of electron localization increasing with the amount of HF exchange. Overall, the performance of the hybrid density functionals does not seem superior to pure density functionals for -Pu.