Spin Spirals in Surface Alloys on Ru(0001): A First-principles Study

摘要

We have used ab initio density functional theory to compute the magneticground states of the surface alloy systems FeAu$_2$/Ru(0001) andMnAu$_2$/Ru(0001). For both systems, we find that the lowest energy magneticconfiguration corresponds to a left-rotating spin spiral, in which the sense ofrotation is determined by the Dzyaloshinskii-Moriya interaction. These spiralsare lower in energy than the ferromagnetic configuration by 3-4 meV per nm$^2$.We also find that FeAu$_2$/Ru(0001) has a significantly high magneticanisotropy energy, of the order 1 meV per Fe atom. By comparing with thecorresponding freestanding alloy monolayers, we find that the presence of theRu substrate plays a significant role in determining the magnetic properties ofthe surface alloy systems.