First-principles study of magnetic interactions in monolayer FeSe

Due to its high-temperature superconductivity, the monolayer FeSe has received considerable attention. Although long-range magnetic order has not been observed, magnetic interactions among local moments of Fe may play important role in the superconducting mechanism. Based on the density-functional theory (DFT) calculations, a large number of magnetic configurations are explored by using supercell and reciprocal-space approaches. Spin models for the monolayer and bulk FeSe, which reasonably account for the DFT results, are constructed.