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

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 neighbors in the periodic table, are weak, leading to the quasiparticle mass enhancement factor m*/m ≈ 1.2. Our results for local spin-spin correlation functions and distribution of weights 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 Q H = (0, 0, 2π/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 Néel temperature with pressure and a breakdown of itinerant antiferromagnetism at pressure of ∼9 GPa in agreement with experimental data, although the Néel temperature is significantly overestimated because of the mean-field nature of DMFT.