Image Simulation of Magnetic Skyrmions on Oxygen Deficient EuO_1-x with Spin-polarized Scanning Tunneling Microscopy

Magnetic skyrmions are topologically protected nanometer-sized nontrivial spin textures. Here we present the simulation images of magnetic skyrmions with spin-polarized scanning tunneling microscopy (SP-STM) on EuO_1-x. With the observed topological hall effect (THE), magnetic skyrmion is suspected to exist in EuO_1-x. Other evidences point to the oxygen vacancies are closely related to this THE related magnetic topological states. Among the various techniques of probing skyrmions, SP-STM is one with direct imaging and high spatial resolution, capable of visualizing non-ordered skymions, in contrast to the skyrmion lattice probed by neutron scattering. SP-STM has ferromagnetic or antiferromagnetic materials on the tip apex. The tunneling current is determined by the angle between the spin orientations of the tip apex and the sample surface. Through simulations, it is concluded that the in-plane (with unknown spin orientation) and out-of-plane spin polarized tip scanning over various types of skyrmion textures could identify the existence of the skyrmions in EuO_1-x. Furthermore, with the known in-plane spin orientation, specific type of skyrmion can be determined.