Coupling of Coexisting Non-Collinear Spin States in the Fe Monolayer on Re(0001)

Spin-polarized scanning tunneling microscopy is used to investigate the magnetic state of the Fe monolayer on Re(0001). Two coexisting atomic-scale non-collinear spin textures are observed with a sharp transition between them on the order of one atomic lattice spacing. A strict position correlation between the two spin states is observed both in experiments and in Monte Carlo simulations, demonstrating their strong coupling behavior.