We study the properties of ${\text{ThCr}}_2{\text{Si}}_2$ structure ${\text{BaMn}}_2{\text{As}}_2$ and ${\text{BaMn}}_2{\text{Sb}}_2$ using density functional calculations of the electronic and magnetic properties as well as experimental measurements on single crystal samples of ${\text{BaMn}}_2{\text{As}}_2$. 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 $\text{Ba}{\left(\text{Fe},\text{Co},\text{Ni}\right)}_2{\text{As}}_2$.

• Received 14 January 2009

DOI:https://doi.org/10.1103/PhysRevB.79.075120