LAUSR

We investigate the interplay between the structural reconstruction and the magnetic properties of Fe double layers on Ir (111) substrate using first-principles calculations based on density functional theory and mapping of the total energies on an atomistic spin model. We show that if a second Fe monolayer is deposited on Fe/Ir (111), the stacking may change from hexagonal-close-packed to bcc (110)-like accompanied by a reduction of symmetry from trigonal to centered rectangular. Although the bcc-like surface has a lower coordination, we find that this is the structural ground state. This reconstruction has a major impact on the magnetic structure. We investigate in detail the changes in the magnetic exchange interaction, the magnetocrystalline anisotropy, and the Dzyaloshinskii-Moriya interaction depending on the stacking sequence of the Fe double layer. Based on our findings, we suggest a technique to engineer Dzyaloshinskii-Moriya interactions in multilayer systems employing symmetry considerations. The resulting anisotropic Dzyaloshinskii-Moriya interactions may stabilize higher-order skyrmions or antiskyrmions.