Universality of Defect-Skyrmion Interaction Profiles*

Magnetic skyrmions are prime candidates for future spintronic devices. However, incorporating them as information carriers hinges on their interaction with defects present in any device. We map from full ab initio[1], the energy profile of single magnetic skyrmions interacting with single-atom impurities, establishing a generic shape as function of the defect's electron filling. Depending on their chemical nature, foreign 3d and 4d transition metal adatoms or surface-implanted defects can either repel or pin skyrmions in Pd/Fe/Ir(111), which we relate to the degree of filling of bonding and anti-bonding electronic states inherent to the proximity of the non-collinear magnetic structure. Similarities with key concepts of bond theories in catalysis and surface sciences imbue the universality of the shape of the interaction profile and the potential of predicting its interaction. The resulting fundamental understanding may give guidance for the design of devices to generate and control skyrmions.
[1] Lima Fernandes I. et al., Nat. Commun. 9, 4395 (2018)