Resolving complex atomic-scale spin structures by spin-polarized scanning tunneling microscopy

The spin-polarized scanning tunneling microscope (SP-STM) operated in the c onstant current mode is proposed as a powerful tool to investigate complex atomic-scale magnetic structures of otherwise chemically equivalent atoms. The potential of this approach is demonstrated by successfully resolving th e magnetic structure of Cr/Ag(111). which is predicted on the basis of ah i nitio vector spin-density calculations to be a coplanar noncollinear period ic 120 degrees Neel structure. Different operating modes of the SP-STM are discussed on the: basis of the model of Tersoff and Hamann.