Itinerant magnetism of chromium under pressure: a DFT+DMFT study

TL;DR

This study uses DFT+DMFT to analyze chromium's electronic and magnetic properties under pressure, revealing weak correlations, absence of local magnetic moments, and pressure effects on antiferromagnetism consistent with experiments.

Contribution

It provides a detailed DFT+DMFT analysis of chromium's itinerant magnetism under pressure, highlighting weak correlations and pressure-dependent magnetic behavior.

Findings

Weak electronic correlations with quasiparticle mass enhancement ~1.2

Local magnetic moments are not formed in chromium

Pressure decreases Néel temperature and leads to antiferromagnetic breakdown around 9 GPa

Abstract

We consider electronic and magnetic properties of chromium, a well-known itinerant antiferromagnet, by a combination of density functional theory (DFT) and dynamical mean-field theory (DMFT). We find that electronic correlation effects in chromium, in contrast to its neighbours in the periodic table, are weak, leading to the quasiparticle mass enhancement factor ${m^*/m \approx 1.2}$. Our results for local spin-spin correlation functions and distribution of weigths of atomic configurations indicate that the local magnetic moments are not formed. Similarly to previous results of DFT at ambient pressure, the non-uniform magnetic susceptibility as a function of momentum possesses close to the wave vector ${{\mathbf Q}_{\rm H}=(0,0,2\pi/a)}$ ($a$ is the lattice constant) sharp maxima, corresponding to Kohn anomalies. We find that these maxima are preserved by the interaction and are not destroyed by pressure. Our calculations qualitatively capture a decrease of the N\'eel temperature with pressure and a breakdown of itinerant antiferomagnetism at pressure of $\sim$9 GPa in agreement with experimental data, although the N\'eel temperature is significantly overestimated because of the mean-field nature of DMFT.