Itinerant antiferromagnetism in BaCr$_2$As$_2$

TL;DR

This study investigates BaCr$_2$As$_2$, revealing it as an itinerant antiferromagnetic metal with distinct magnetic order and stronger covalency than Fe-based counterparts, providing insights into doping effects and electronic structure.

Contribution

It provides the first comprehensive synthesis, measurements, and electronic structure calculations for BaCr$_2$As$_2$, highlighting its unique magnetic and electronic properties compared to Fe-based superconductors.

Findings

BaCr$_2$As$_2$ is an itinerant antiferromagnetic metal.

Mass renormalization factor is approximately 2.

Stronger transition metal-pnictogen covalency than Fe compounds.

Abstract

We report single crystal synthesis, specific heat and resistivity measurements and electronic structure calculations for BaCr$_2$As$_2$. This material is a metal with itinerant antiferromagnetism, similar to the parent phases of Fe-based high temperature superconductors, but differs in magnetic order. Comparison of bare band structure density of states and the low temperature specific heat implies a mass renormalization of $\sim$ 2. BaCr$_2$As$_2$ shows stronger transition metal - pnictogen covalency than the Fe compounds, and in this respect is more similar to BaMn$_2$As$_2$. This provides an explanation for the observation that Ni and Co doping is effective in the Fe-based superconductors, but Cr or Mn doping is not.