Monte Carlo Study of Room-Temperature Ferromagnetism in C-Doped ZnO

The room-temperature ferromagnetism of diluted magnetic semiconductors (DMS) doped with light elements has been extensively studied for potential applications in spintronic devices. The existence and stability of ferromagnetism of DMS with low concentration regime is an interesting topic, followed by researches using both Monte Carlo (MC) simulation and first-principle calculations. Both continuous and discrete spin models were developed to describe the ferromagnetic phase but it is still unclear, which one produces a better outcome. To clarify the issue of a continuous spin model versus a discrete spin model, we have performed a large-scale MC simulation of C-doped ZnO system. We found that the discrete spin model exhibit magnetic phase transition at near room-temperature while the continuous spin model does not show phase transition in the investigated low temperature range.