Interplay of carrier free and carrier mediated magnetism in Mn doped LiZnAs

The interplay of superexchange and Zener/RKKY and its influence on dopant distribution is studied by model systems of Mn doped LiZnAs based on density functional theory (DFT) calculations. We found that in carrier free configurations, it favors short range magnetic interaction. However, when hole is introduced, the interplay mechanism between the super exchange and the band coupling mechanism dramatically changes the magnetic coupling distance and the type of magnetic coupling. As a result, the short range ferromagnetism almost vanishes while the long range ferromagnetism remains strong. This discovery contradicts the “common sense” that magnetic interaction is strongest in the short range and decay with distance. Such interplay may be promising in designing strategies that promote stable long range magnetic configuration in experiments, which is the key to realize dilute magnetic semiconductor devices.