First-principles study of the magnetic properties of Mn-related binary compounds

Abstract

Based on first-principles spin-density-functional calculations, we study the magnetic properties of MnX binary compounds (X=N,P,As and Sb). We investigate the structural stability of the NiAs and zincblende structures within the generalized gradient approximation. Our calculations well reproduce experimental results for the lattice parameters, magnetic moments, and magnetic ground states. The magnetic moment of Mn ions shows a tendency to increase as the anion quantum number increases, and is more enhanced in the zincblende phase except for MnN. This behavior can be explained by d-d overlap and p-d hybridization. For MnAs nd MnSb, a ferromagnetic (FM) spin configuration is found to be more stable than an antiferromagnetic (AFM) state, while MnP favors the AFM state at 0 K. We find that volume is deeply related to magnetic moment and magnetic stability and thus suggest that the AFM-to-FM transition of MnP has its origin in volume change by temperature.