Giant magnetization canting due to symmetry breaking in zigzag Co chains on Ir(001)

Wedemonstrate a canted magnetization ofbiatomic zigzag Co chains grown on the (5 × 1) recon- structed Ir(001) surface using density functional theory(DFT) calculations and spin-polarized scan- ning tunneling microscopy(SP-STM) experiments. It is observed bySTM 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 symmetrydue to two equivalent atomic strands and an easy magnetization direction that is along one ofthe principal crystallographic axes. The easy magnetization axis ofthe zigzag Co chains is canted awayfrom the surface normal byan angle of33°. This giant effect is caused bythe broken chain symmetryon the substrate in combination with the strong spin–orbit coupling ofIr. SP-STM measurements confirm the stable FMorder ofthe zigzag chains with a canted magnetization.