Electronic structure and Magnetism in BaMn$_2$As$_2$ and BaMn$_2$Sb$_2$

TL;DR

This study combines density functional calculations and experimental measurements to analyze the electronic structure and magnetic properties of BaMn$_2$As$_2$ and BaMn$_2$Sb$_2$, revealing their semiconducting antiferromagnetic nature and potential for thermoelectric applications.

Contribution

It provides new insights into the electronic and magnetic properties of BaMn$_2$As$_2$ and BaMn$_2$Sb$_2$, highlighting their hybridization and intermediate spin state, and discusses their relation to iron-based superconductors.

Findings

BaMn$_2$As$_2$ and BaMn$_2$Sb$_2$ are local moment antiferromagnetic semiconductors.

Substantial Mn-pnictogen hybridization stabilizes an intermediate spin state.

Potential applications in thermoelectric devices are discussed.

Abstract

We study the properties of ThCr$_2$Si$_2$ structure BaMn$_2$As$_2$ and BaMn$_2$Sb$_2$ using density functional calculations of the electronic and magnetic as well experimental measurements on single crystal samples of BaMn$_2$As$_2$. These materials are local moment magnets with moderate band gap antiferromagnetic semiconducting ground states. The electronic structures show substantial Mn - pnictogen hybridization, which stabilizes an intermediate spin configuration for the nominally $d^5$ Mn. The results are discussed in the context of possible thermoelectric applications and the relationship with the corresponding iron / cobalt / nickel compounds Ba(Fe,Co,Ni)$_2$As$_2$.