Dynamical correlations and screened exchange on the experimental bench: spectral properties of the cobalt pnictide BaCo2As2

TL;DR

This paper introduces a new computational approach combining screened exchange and dynamical correlations to accurately predict the spectral properties of BaCo2As2, resolving discrepancies in its magnetic behavior.

Contribution

The study develops a novel method that improves electronic structure calculations by integrating screened exchange with local dynamical correlations for correlated materials.

Findings

Successfully predicts the non-magnetic ground state of BaCo2As2

Resolves the ferromagnetic instability puzzle in standard calculations

Provides insights into low-energy excitations of cobalt pnictides

Abstract

Understanding the Fermi surface and low-energy excitations of iron or cobalt pnictides is crucial for assessing electronic instabilities such as magnetic or superconducting states. Here, we propose and implement a new approach to compute the low-energy properties of correlated electron materials, taking into account both screened exchange beyond the local density approximation and local dynamical correlations. The scheme allows us to resolve the puzzle of BaCo2As2, for which standard electronic structure techniques predict a ferromagnetic instability not observed in nature.