Neutron magnetic form factor in strongly correlated materials

TL;DR

This paper presents a first-principles method combining DFT and DMFT to accurately compute the neutron magnetic form factor in strongly correlated materials, capturing spin and orbital effects.

Contribution

The authors develop a novel formalism integrating DFT and DMFT for calculating magnetic form factors, applicable to mixed-valence and strongly correlated systems.

Findings

PuCoGa5 is in a mixed-valence state.

The method accurately reproduces measured magnetic form factors.

Applicable to actinides like NpCoGa5, PuSb, and PuCoGa5.

Abstract

We introduce a formalism to compute the neutron magnetic form factor Fm(q) within a first-principles Density Functional Theory (DFT) + Dynamical Mean Field Theory (DMFT). The approach treats spin and orbital interactions on the same footing and reduces to earlier methods in the fully localized or the fully itinerant limit. We test the method on various actinides of current interest NpCoGa5, PuSb and PuCoGa5; we show that PuCoGa5 is in mixed valent state, which naturally explains the measured magnetic form factor.