Accounting for spin fluctuations beyond LSDA in the density functional theory

TL;DR

This paper introduces a correction method for LSDA in density functional theory to better predict magnetic properties in itinerant systems, successfully applied to Ni3Al to match experimental Curie temperature scaling.

Contribution

A new correction approach for LSDA that accounts for spin fluctuations, improving magnetic property predictions in itinerant electron systems.

Findings

Corrects LSDA magnetic properties in Ni3Al under pressure

Reproduces critical fluctuation scaling consistent with Moriya's theory

Accurately predicts pressure-dependent magnetic moments and Curie temperature

Abstract

We present a method to correct the magnetic properties of itinerant systems in local spin density approximation (LSDA) and we apply it to the ferromagnetic-paramagnetic transition under pressure in a typical itinerant system, Ni$_{3}$Al. We obtain a scaling of the critical fluctuations as a function of pressure equivalent to the one obtained within Moryia's theory. Moreover we show that in this material the role of the bandstructure is crucial in driving the transition. Finally we calculate the magnetic moment as a function of pressure, and find that it gives a scaling of the Curie temperature that is in good agreement with the experiment. The method can be easily extended to the antiferromagnetic case and applied, for instance, to the Fe-pnictides in order to correct the LSDA magnetic moment.