Giant Magnetization Canting Due to Symmetry Breaking in Zigzag Co Chains on Ir(001)

Wedemonstrate a cantedmagnetization of biatomic zigzag Co chains grown on the (5 × 1) reconstructed Ir(001) surface using density functional theory (DFT) calculations and spin-polarized scanning tunnelingmicroscopy (SP-STM) experiments. It is observed by STM that biatomic Co chains grow in three different structural configurations. OurDFT calculations show that they are all in a ferromagnetic (FM) state. Two chain types possess high symmetry due to two equivalent atomic strands and an easymagnetization direction that is along one of the principal crystallographic axes. The easymagnetization axis of the zigzag Co chains is canted away from the surface normal by an angle of 33°. This giant effect is caused by the broken chain symmetry on the substrate in combinationwith the strong spin–orbit coupling of Ir. SP-STMmeasurements confirm the stable FMorder of the zigzag chainswith a cantedmagnetization.