Ab-initio study of the electronic structure and magnetic properties of ACr2Pn2 (A =Ba, Sr, Ca, Sc, K; Pn=As, P)

We study the electronic structure and magnetic interactions of ten layered chromium tetragonal pnictides ACr(2)Pn(2) (A = Ba, Sr, Ca, Sc, K, and Pn = As, P) using first-principle density functional theory calculations. The structural parameters such as lattice constants, internal atomic parameters, interatomic distances, and angles for these systems compare quite well with experimental results. DFT results indicate that the antiferromagnetic Neel-type order with AFM interlayer coupling is favorable on the chromium atoms for all studied conductor materials except for CaCr2As2 and KCr2As2 compounds that adopt the antiferromagnetic Neel-type order with FM interlayer coupling and the nonmagnetic order respectively. Exchange interaction parameters are calculated using the J(1)-J(2)-J(c) Heisenberg model with in-plane nearest-neighbor (J(1)), in-plane next-nearest-neighbor (J(2)), and out-of-plane nearest-neighbor (J(c)). The Neel temperatures of ACr(2)Pn(2) conductor materials were also calculated using the Mean Field Approximation (MFA) and the Classical Monte-Carlo (CMC) simulation. In this series of compounds, the magnetic moment varies from 1.11 mu(B) to 2.26 mu(B) and is located around each Cr ion indicating an environment of itinerant magnetism.