Dynamical nonlocal coherent-potential approximation for itinerant electron magnetism

TL;DR

This paper introduces a dynamical extension of the nonlocal coherent-potential approximation to better understand itinerant electron magnetism, emphasizing the role of dynamical correlations in local moment formation.

Contribution

It develops a variational dynamical nonlocal CPA based on functional integrals, highlighting the importance of dynamical correlations in magnetic properties.

Findings

Dynamical correlations significantly influence local moment formation.

Static approximation captures essential effects of nonlocal physics.

The approach provides a new framework for studying itinerant electron magnetism.

Abstract

A dynamical generalisation of the nonlocal coherent-potential approximation is derived based upon the functional integral approach to the interacting electron problem. The free energy is proven to be variational with respect to the self-energy provided a self-consistency condition on a cluster of sites is satisfied. In the present work, calculations are performed within the static approximation and the effect of the nonlocal physics on the formation of the local moment state in a simple model is investigated. The results reveal the importance of the dynamical correlations.